Physics Division Report of the Division Head

General Remarks programs, it is aiming to stimulate better research and foster greater collaboration among researchers Taiwan in the 3rd phase. Most importantly, through the participation of international researchers in the CTS enters the operation of the 3nd activities of focus groups, the visibility of phase early this year. The 6-year theoretical researches in Taiwan can be further endorsement from National Science Council increased. Therefore, we expect more intensive (NSC) has enabled the center for long-term international exchanges with theoretical scientists planning. In the 3rd phase, NCTS follows the from all over the world, in particular with other format established in the 2nd phase with the main world renowned research centers of theoretical project being located at National Tsing Hua sciences in the 3rd phase. University (NTHU), subproject I being at National Before we report academic activities and Taiwan University (NTU), and subproject II being highlights of researches in 2009, I want to take located at National Cheng-Kung University this opportunity to welcome Professor Ling-Fong (NCKU). In addition to NTHU and National Li (李靈峰) from Carnegie Mellon University, Chiao Tung University (NCTU), National Central who has kindly accepted the offer to head the University (NCU) joins and co-hosts the main Division. Professor Li will inaugurate in January project. For physics programs, subproject I is led 2010. In the following, we shall first describe the 侯維恕 by Professor Wei-Shu Hou ( ) from the operation structure for the 3rd phase. Detailed Physics Department of NTU, while the subproject reports on each focus group and topical program 盧炎 II is currently led by Professor Yan-Tien Lu ( can be found on the NCTS web-site http://phys. 田 ) from the Physics Department of NCKU. The cts.nthu.edu.tw/. annual budget allocation of NCTS in the 3rd phase will be determined based on annual review. Organization Structure In 2009, about one-third and one-sixth of the NCTS annual budget are channeled through The operation of the Physics Division is Subproject I and Subproject II at NCKU, conducted with the help of the executive respectively. The rest of the NCTS budget is committee. Division head and PIs of subprojects allocated in the main project. (Professors Wei-Shu Hou and Yan-Tien Lu) are default members in the committee. In 2009, the In the 3rd phase, the Division continues to rest members are Professor Pei-Long Chen (陳培 implement focus groups as the main academic 亮, NCU), Professor Yung-Chung Chen (陳永忠, program. In addition, the Division will also play a Tunghai University), Professor Chon-Saar Chu more dominant role by selecting important topics (朱仲夏, NCTU), Professor Guang-Yu Guo that may lead to works with wide impact and (郭光宇, NTU), Professor Kin-Wang Ng (吳建宏, organize these topics as topical programs. The Academia Sinica (AS)), Professor Shiow-Fon main project and subprojects support all activities Tsay (蔡秀芬, National Sun Yat-sen University) of focus groups together, while the NCTS and physics review-panel convener of NSC scientific personnel, and the additional NCTS (Professors Chia-Seng Chang (張嘉升, AS) and sponsored functions, such as topical programs and Jow-Tsong Shy (施宙聰, NTHU)). Members of the joint programs between Physics and Executive Committee represent various fields in Mathematics Division are supported by the main theoretical physics, providing opinions and project. Through the organization of nationwide suggestions based on their expertise, and serving

Report of the Division Head -›› 130 as the second reviewers of applications and Pohang on quantum condensation. Six delegates recruitments submitted to NCTS. supported by NCTS attended the program. The workshop extended for 2 weeks and is aiming for In addition to the executive committee, an inducing possible cooperated researches. During annual review will be performed each year in the rd the period of the workshop, the interaction among 3 phase. The annual review for 2009 will take Taiwan delegates and other foreign participants place on Dec. 26. The function of the annual was intensive. Some projects were initiated. To review committee takes over that of the nd continue the joint effort and projects, the same performance evaluation panel in the 2 phase joint workshop will be held at NCTS in August except that it is formed by NSC. In addition, the 2010 with anticipated number of participants review committee gives recommendation on being around 20. Another joint workshop with budget of the following year to NSC. APCTP is the workshop on multiferroics which Scientific Activities will be held in early January of 2010 in Taiwan. This workshop will bring theorists and Except for a couple of mini-workshops experimentalists together both from Taiwan and organized by center staff scientists, the majority of abroad and is aiming to induce timing cooperated the scientific activities in the physics division are researches in the subject of multiferroics. planned and carried out by the NCTS affiliated focus groups. All NCTS sponsored activities have In addition to the existing international been posted on the NCTS web-site at http://phys. cooperation, NCTS is also exploring possible cts.nthu.edu.tw/ as soon as it is planned, and also cooperation with theoretical institutes in France. stayed on the web-site afterwards as a future For this purpose, a Taiwan-France workshop on reference. In addition to focus groups, the theoretical sciences was held in October. This is a Division selected Laser/Maser Plasma Science as workshop organized jointly with the mathematical a topical program with emphasized on physics of division. Four French delegates with two laser-wake plasma. The coordinator is Prof. Shih- physicists came to join the workshop. The Hung Chen of NCU. The program is jointly workshop ends with a mutual understanding organized with a strong local experimental group between NCTS and France to organize joint (with 100-TW laser available) led by Prof. academic program in the future. 汪治平 Jyhpyng Wang ( ) from AS. With efforts To nurture young theorists in various fields, 14 from both theorists and experimentalists, the schools on different subjects were organized in program is aiming to further promote visibility 2009. In particular, the Division organized a and cooperated researches of researchers in the summer school on theoretical physics for area of large-scale laser/maser plasma simulation. undergraduates in July. It was aiming to attract In 2009, in addition to focus groups and good students to join theoretical researches. There topical programs, three initiative programs (Build- were 66 undergraduate students from various up of Theory Support for LHC Physics, Establish universities in Taiwan participating in this 2-day GPU-based Supercomputing Platform, and Theory school. The school was met with a lot of and Simulation of Plasmonic Meta-materials) are undergraduate students who show great interest in proposed and operated by subproject I. Even theoretical physics. It appears that the school though these programs do not follow the normal provides a good opportunity for undergraduate procedure that programs were proposed and students to appreciate theoretical physics and we operated in the division, they will be also shall continue it in 2010 with more careful reviewed and the reports of their activities will designing lectures involved. In addition, a summer also be described in the following report. course on quantum field theory was also organized by the Center. This course was mainly A number of activities in 2009 were performed lectured by Prof. Ling-Fong Li from Carnegie through international collaborations with foreign Mellon University and provides an entry point for physics centers. In particular, a joint KITP-type students who want to join researches on particle workshop with Asia Pacific Center for Theoretical physics. Physics (APCTP) was organized in August at

131 ‹‹- Report of the Division Head Highlights of Researches models. These works were published in Phys. There are quite a number of excellent research Lett. B678, 293 (2009); JCAP910, 001 (2009); results generated by activities of NCTS. In the Phys. Lett. B675, 77 (2009); Phys. Lett. B678, followings, I shall highlight representatives. 168, (2009); Mod. Phys. Lett. A24, 2139, (2009) Details of highlights for individual focus group and have been cited well. In addition to these can be found in the following report. published work, two discussion sessions on experimental data and theoretical ideas were also In a joint effort to understand the recently organized with LHC Physics Focus group and observed gigantic spin Hall effect in FePt/Au cosmology and astrophysics Focus group were 郭光 system at room temperature, Guang-Yu Guo ( also organized. Some of the models proposed may 宇 , NTU) and his cooperators revealed the orbital- be further tested at the LHC. dependent Kondo effect in Fe impurity in Au by performing ab initio electronic structure Recruitment and Scientific Staff calculations for various transition metal impurities There are several members departing from the in gold. In particular, they demonstrated that the Physics Division in 2009. Among the recent giant hall effect is due to resonant skew scattering departures, Dr. David Adams, a visiting assistant enhanced by multi-orbital Kondo effect. This professor of NCTS at Taipei office, was recruited fascinating result relates the spin Hall effect to the by Nanyang Technological University as an classic Kondo problem in condensed-matter assistant professor. Dr. Shih-Yuin Lin (林世昀) physics. It was published in Phys. Rev. Lett. 102, joined as an assistant research scholar in National 036401 (2009) and was selected as a viewpoint in Cheng Kung University. Other departure includes Physics. Dr. Chih-Hao Chen (陳志浩), who joins Institute In another joint work of Ying-Jer Kao (高英哲, of Systems Biology and Bioinformatic at NCU. NTU) and his coworkers, it is demonstrated that, To maintain viable supporting scientific using Zn-doped La2CuO4 as an example, a personnel, the Physics Division continues to spinless impurity doped into a non-frustrated recruit staff scientists in the past year. The antiferromagnet can induce substantial frustrating recruitment in 2009 is quite fruitful. In particular, interactions among the spins surrounding it. This Professor Ling-Fong Li has agreed to lead the work results from past effort of members for division. Professor Li will inaugurate in Jan. 2010. developing numerical methods for strongly In addition, four new members have joined the correlated physics and is published in Phys. Rev. Physics Division: Dr. Eibun Senaha (Particle Lett. 102, 167201 (2009). The result has provided Physics), Dr. Takayuki Hirayama (String), Dr. Pei- the key to resolve long-standing discrepancies Jen Lin (林佩真, Condensed Matter Physics), and between experimental data and earlier theories and 陳俊仲 is expected to provide a common mechanism for Dr. Chun-Chung Chen ( , Soft Condensed other correlated oxides as well. Matter Physics). In 2009, there are seven long- term visiting professors joining the Division. During the past two years, triggered by Among them, Professor Abdesslam Arhrib evidences of dark matter from Pamela, ATIC, and (visiting associate Professor, High Energy FERMI-LAT data, showing that there are excesses Physics) joined the Physics Division at Taipei in cosmic e+ and e-, tremendous work has been office. Professors Vidar Gudmundsson (visiting devoted to explain these excesses. Members in the professor, condensed matter physics) and Ling- LHC Physics Focus group and cosmology and Fong Li join the Division at Hsinchu. The astrophysics Focus group were able to catch the Division also made an offer to Dr. Ming-Chiang research front and had published important papers Chung (張明強, condensed matter physics), who on this subject. One of the possible sources for will join the center in Feb. 2010. these excesses is from dark matter annihilation or Finally, through the Center Scientist program, dark matter decay. A number of members in these t h e P h y s i c s d i v i s i o n h a s r e n e w e d t h e focus groups have proposed model independent appointments of Professors Kingman Cheung (張 analysis of dark matter properties, dark matter 敬民, NTHU), Yuen-Nan Chen (陳岳男, NCKU), decay models, and dark matter annihilation and David Lin (林及仁, NCTU) as center

Report of the Division Head -›› 132 scientists. The appointment of Prof. Cheung is community, I am confident that the Center has the renewed at senior level and is demanded by the potential to mature into a world class center for leadership in his research field, while Profs. Chen theoretical sciences. and Lin are renewed as Junior Center Scientists. Since this is my last report as the Division Head, I would like to take this opportunity to Conclusions and Acknowledgement thank many colleagues in Taiwan for their support As noted at the beginning, in the year 2009, during the past two years. I would especially like NCTS is going into the 3rd phase with 6-year to thank Professor Chon-Saar Chu for helping me endorsement from NSC. In the 3rd phase, the in taking care of numerous administrative work. I Physics Division also made some adjustment in am confident that under the new leadership of organization to strengthen the coherence of Professor Ling-Fong Li, the NCTS Physics operations. After 12-year operation, the Physics Division will enjoy success for the following Division now has more experience about years. successful operational strategies. The Division will continue to operate based on its current strength and improve areas that have not been Chung-Yu Mou (牟中瑜) doing well. With continued support from the November 2009 government and strong support from the physics

133 ‹‹- Report of the Division Head Highlights of Programs Complex Systems and Soft Matter

Focus Group on Critical Phenomena and Complex Systems

Coordinator: Chin-Kun Hu (Academia Sinica; email: [email protected]) Committee Members: Hu-Chiuan Chang (National Cheng Kung University), Chi-Ming Chen (National Taiwan Normal University), Chi-Ning Chen (National Dong Hwa University), Shu-Heng Chen (National Chengchi University), Wen-Jer Tzeng (Tamkang University), Chung-I Chou(Chinese Culture University), Ming-Chung Ho (National Kaoshiung Normal University), Ming-Chang Huang (Chung-Yuan Christian University), I-Ming Jiang (National Sun-Yat Sen University), Chai-Yu Lin (National Chung Cheng University), Ning-Ning Pan (National Taiwan University), Ming-Chya Wu (Academia Sinica)

I. Brief Description Department of Physics of National Kaohsiung Normal University, Ming-Chang Huang (黃敏 章) at Department of Physics of Chung-Yuan Christian University, Tai-huang Huang (黃太 煌 A.  he purpose of this FG is to develop ) at Institute of Biomedical Sciences of 姜一民 ideas and methods in statistical and Academia Sinica, I-Min Jiang ( ) at nonlinear physics, then apply such ideas and Department of Physics of National Sun Yat-sen 李柏翰 methods to complex physical, biological, and University, Po-han Lee ( ) at The social problems. The focus research topics Affiliated Senior High School of National 林財 include (1) Theoretical models of critical Taiwan Normal University, Chai-Yu Lin ( 鈺 phenomena, chaos, and pattern formation, (2) ) at Physics Department of National Chung 林榮信 Structures, folding, aggregation, and evolution Cheng University, Jung-Hsin Lin ( ) at of biological macromolecules, (3) Modeling Research Center for Applied Sciences & and analysis of complex network and signals. Institute of Biomedical Sciences of Academia 羅煜聘 The activities of this FG can be found at Sinica, Yu-Pin Luo ( ), Department of “Activity” of LSCP website: http://proj1. Electronic Engineering of National Formosa 施奇廷 sinica.edu.tw/~statphys/. U n i v e r s i t y, C h i - T i n S h i h ( ), Department of Physics of Tunghai University, B. The key researchers of this FG include (1) 曾文哲 張書銓 Wen-Jer Tzeng ( ) at Department of Shu-Chiuan Chang ( ) at Physics Dept. Physics of Tamkang University, Dr. Ming- of National Cheng-Kung University, Chi-Ning 吳明佳 陳企寧 Chya Wu ( ) at Research Center for Chen ( ) at Physics Department of Adaptive Data Analysis of National Central National Dong-Hwa University, Dr. Yi-Chiuan U n i v e r s i t y, J u i-L i n g Yu (余瑞琳) a t Chen (陳怡全), Institute of Mathematics of 鄒忠毅 Department of Applied Mathematics of Academia Sinica, Chung-I Chou ( ) at Providence University, Zicong Zhou (周子聰) Department of Physics of Chinese Culture at Department of Physics of Tamkang University, Ming-Chung Ho (何明宗) at

Highlights of Programs -›› 134 University.(2) Long term visitos: D. Y. Lando Short term visitors can be found from speakers from Belarus National Academy of Sciences, of BioComplex-Taiwan-2009 and Workshops BELARUS; N. Sh. Izmailian from Yerevan listed in II.A. We are collaborating with visitors State University in Armenia; David B. Saakian on following problems. from Yerenan Physics Institute in Armenia, (3) [1] Po-han Lee, T. Hwa (U.C. San Diego), A. E. Postdoctoral fellow: Shura Hayryan, Yao-Chen Allahverdyan (Yerevan Physics Inst) and Hung, Wen-Jong Ma and Karen Petrosyan at C.-K. Hu will collaborate to study Inst of Phys. Of Academia Sinica; Chia-Hei polymorphism and sympatric speciation in Yang at Department of Physics of Tunghai bacteria. Univ.; Chung-ke Chang at Institute of Biomedical Sciences, Academia Sinica (4) [2] Shura Hayryan, Ming-Chya Wu and Chin- Ph.D. students: Chun-Ling Chang at Natl Kun Hu in collaboration with Prof. Nikolay V. Central Univ, Hsin-Ling Jiang at Natl-Hsing Dokholyan’s group at North Carolina are Hua Univ, Chien-Zhong Wang at Natl Chung establishing database and website for three- Hsin Univ, Shi-Jie Wang at Natl Chung Hsin dimensional structures of microRNA. Univ. [3] Ming-Chya Wu, Yao-Chen Hung, Shi-Jie Wang, Chin-Kun Hu, in collaboration with Z. II. Activities R. Struzik and Y. Yamamoto at University of A. Academic Activities (see “Activities” at http:// Tokyo are analyzing physiological signals to proj1.sinica.edu.tw/~statphys/). identify health problems in human subjects. [1] We organized a series of four 2009 NCTS [4] Hsin-Ling Jiang, Wen-Jong Ma, Yun-Ru Chen Workshops on Critical Phenomena and (Genomics Res Center of AS), Rita Chen Complex Systems on 27 & 30 March, 12, 13 (Inst. Bio. Chem., AS), and Chin-Kun Hu in &15 June, 24, 27 & 28 July, and 25 & 28 collaboration with Mai-Suan Li (Polish September 2009. Academy of Sciences) and Hisashi Okumura [2] We are organizing BioComplex- (Institute for Molecular Science at Okazaki,) Taiwan-2009:2009 Taiwan International to work on protein folding and aggregation Workshop on Biological Physics and Complex problems. Systems at AS on 10-13 December and at [5] Jui-Ling Yu and Prof. Olga. S. Rozanova of Chung-Yuan Christian University on 14-15 Department of Math. at Moscow State December 2009. University are establishing a mathematical B. Train young-generation physicists: model for predicting the trajectory of typhoon on curved space. [1] Shu-Chiuan Chang, Chi-Ning Chen, Chai-Yu Lin, and Jui-Ling Yu, Wen-Jer Tzeng visited [6] Chi-Ning Chen and Prof. Jonathan Dushoff NCTS (North) in the summer break of 2009. (Department of biology, McMaster University, CANADA) are working on a model for [2] Ph.D. student Mr. Shi-Jie Wang visited disease spreading. University of Tokyo for one week to collaborate with Prof. Nobuyasu Ito’s group at [7] Ming-Chang Huang and Prof. N. Sh. Department of Applied Physics on analysis of Izmailian from Yerevan State University in complex human network. Armenia are working on lattice models of critical phenomena. (3) Ph. D student Hsin-Ling Jiang visited Institute for Molecular Science at Okazaki, Japan for IV. Highlights of Research Results one month to collaborate with Prof. Hisashi A. Highlights of Research Results: Okumura’s group on protein folding and aggregation. 1. Development of a theory of biological polymorphism under periodic fast varying III. Visitors and International environments [A. E. Allahverdyan and C.-K. Collaborations Hu, Phys. Rev. Lett. 102, 058102 (2009).].

135 ‹‹- Highlights of Programs 2. Classification of human ventricular fibrillation talks, Shu-Chiuan Chang, Chung-I Chou, Wen- ECG (Electrocardiography) time series into Jer Tzeng and Zicong Zhou gave invited talks three types (uniform UF, concave CC, and at “The 5th Cross Strait Conference on convex CV) by using phase statistics approach Statistical Physics” at Nanjing Normal Univ. and find that UF and CC types have about the on 13-15 August 2009. same probability of survival and non-survival, CV type has zero probability of survival [M.-C. V. Publications Wu, et al. Phys. Rev. E 80, Nov. (2009)]. Only list 2009 papers. Selected ones are good 3. Establishment of database and website for enough. three-dimensional structures of micoRNA in A. Papers with NCTS as the affiliation. collaboration with Prof. Nikolay V. Dokholyan’s group at North Carolina. 1. D. B. Saakian, C. K. Biebricher,and C.-K. Hu, Phase diagram for the Eigen quasispecies 4. Using a formula by F. Y. Wu to express the theory with the truncated fitness landscape, Potts model partition function as a sum over Phys. Rev. E 79, 041905 (2009). spanning subgraphs, S.-C. Chang proved some properties of the partition function concerning 2. O. S. Rozanova, J.-L. Yu, and C.-K. Hu, factorization, monotonicity, and zeros. It Typhoon eye trajectory based on a follows that the Tutte polynomial can also be mathematical model: comparing with generalized. [ J. Phys. A: Math. Theor. 42, observational data, Nonlinear Anal. Real World 385004 (2009)]. Appl. (2009) B. Invited Presentations: 3. S.-C. Chang, Spanning trees on two- dimensional lattices with more than one type of 1. Chin-Kun Hu gave (1) a plenary talk on vertex, J. Phys. A: Math. The. 42, 015208 “Molecular models of the origin of life and (2009) (21 pages) biological evolution” at “The First International Conference on Complex 4. C.-Y. Lin, A Renormalization-group Approach Sciences: Theory and Applications (Complex to the Manna Sandpile, Phys. Rev. E, submitted 2009)” at University of Shanghai for Science (2009). and Technology in Shanghai, China on 23-25 B. Papers acknowledged NCTS supports: February 2009, (2) an invited talk “Some universal patterns in human activities” at 1. A. E. Allahverdyan and C.-K. Hu, Replicators APFA7 Satellite Workshop: “Can we simulate in fine-grained environment: Adaptation and the whole human society?” at Yayoi polymorphism, Phys. Rev. Lett. 102, 058102 Auditorium of the University of Tokyo, On 6 (2009). March 2009, (3) an invited talk on “Molecular 2. C.-K. Chang, Y.-l. Hsu, Y.-H. Chang, F.-A. dynamics approach to relaxation and Chao, M.-C. Wu, Y.-S. Huang, C.-K. Hu, T.-H. aggregation of polymer chains” at the Huang, Multiple nucleic acid binding sites and workshop “Frontiers of Non-equilibrium intrinsic disorder of SARS coronavirus Physics: Fundamental theory, glassy and nucleocapsid protein - implication for granular materials, and computational physics” ribonucleocapsid protein packaging, J. at Kyoto University on 21 July-21 August Virology 83, 2255-2264 (2009). 2009, (4) a plenary talk at “The 5th Cross Strait 3. A. E. Allahverdyan, Zh.S. Gevorkian, C.-K. Conference on Statistical Physics” at Nanjing Hu, and Th.M. Nieuwenhuizen, How Normal University on 13-15 August 2009. adsorption influences DNA denaturation, Phys. 2. Ming-Chya Wu and Ming-Chang Huang gave Rev. E 79, 031903 (2009). invited talks at Oversea Chinese Physicist 4. J. S. Kim, B. Kahng, and D. Kim, Association (OCPA) Conference at Lanzhou, Disassortativity of random critical branching China on 3-7 August 2009. trees, Phys. Rev. E 79, 067103 (2009). 3. Ming-Chung Ho and I-Min Jiang gave plenary 5. M.-C. Wu, E. Watanabe, Z. R. Struzik, C.-K.

Highlights of Programs -›› 136 Hu, and Y. Yamamoto, Phase statistics 10. S.-C. Chang and R. Shrock, Some exact approach to human ventricular fibrillation, results on the Potts model partition function Phys. Rev. E 80, Nov (2009), in a magnetic field, J. Phys. A: Math. The. 42, 385004 (2009) (5 pages) 6. H.-J. Fang, Y.-Z. Chen, M. S. Li, M.-C. Wu, C.-L. Chang, C.-k. Chang, Y.-l. Hsu, T.-h. 11. H. L. Chen, C.-c. Hsu, M.-H. Viet, M. S. Li, Huang, H.-M. Chen, T.-Y. Tsong, and C.-K. C.-K. Hu, C.-H. Liu, F. Luk, E. Chang, A. Hu. Thermostability of the N-terminal RNA- Wang, M.-F. Hsu; W. Fann and R. Chen, binding domain of the SARS-CoV Studying the fast folding kinetics of an nucleocapsid protein: Experiments and antifreeze protein RD1 using a photolabile numerical simulations, Biophys. J. 96, 1892- caging strategy and time-resolved 1901 (2009). photoacoustic calorimetry on a nanosecond timescale, J. American Chem. Society, 7. J. Busa, S. Hayryan, C.-K. Hu, J. Skrivanek, submitted. and M.-C. Wu, Enveloping triangulation method for detecting internal cavities in 12. W.-J. Ma and C.-K. Hu, Molecular dynamics proteins and algorithm for computing their approach to relaxation and aggregation of surface areas and volumes, J. Comp. Chem. 30, polymer chains, to be published. 346-357 (2009). 13. M.S Li, N. T. Co, C.-K. Hu and D. 8. N. Sh. Izmailian and C.-K. Hu, Boundary Thirumalai. Factors governing fibrillogenesis conditions and amplitude ratios for finite-size of polypeptide chains, Phys. Rev. Lett., corrections of a one-dimensional quantum spin submitted. model, Nucl. Phys. B 808, 613 (2009) 14. Y.-C. Hung and C.-K. Hu. Stochastic 9. B. C. Bag and C.-K. Hu, Current inversion resonance in p53 regulatory network, Phys. induced by colored non-Gaussian noise, J. Stat. Rev. Lett., submitted Phys., p02003 (2009).

137 ‹‹- Highlights of Programs Focus Group on Soft Matter Physics

Coordinator: Hsuan-Yi Chen (National Central University; email: [email protected]), Paul Hoong-Chien Lee (National Central University; email: [email protected]), Ming-Chih Shih (National Chung Hsing University; email: [email protected]) Committee Members: Hsien-Da Huang (National Chiao Tung University), Hsueh-Fen Juan (National Taiwan University), Pik-Yin Lai (National Central University), Chun-Yi Lu (National Taiwan University), Sy-Sang Liaw (National Chung Hsing University), Jiunn-Ren Roan (National Chung Hsing University), Kai-Jung Chi (National Chung Hsing University), Jeng-Tze Yang (National Chung Hsing University)

I. Brief Description interdisciplinary nature of our FG, some members are from departments of life sciences and mathematics. The main research topics of the members of our he key members of this focus group FG include: include: 1. Neuron and other cell culture networks Bio-soft Matter (BSM): 2. Biomembranes, cytoskeleton, and other Pik-Yin Lai (NCU Phys), Peilong Chen (NCU biomaterials including spider webs Phys), Hsuan-Yi Chen (NCU Phys), Heng-Kwong 3. Pattern formation and nonlinear dynamics, Tsao (NCU ChemEng), Ya-Wei Hseuh (NCU including time sequences analysis Phys), Chien-Jung Lo (NCU Phys), Chi-Lun Lee 4. Complex fluids, including granular matter (NCU Phys), Chi-Keung Chan (Academia Sinica Phys), Keng-Hui Lin (Academia Sinica Phys), 5. Biomemchanics, for example the effect of Kwan-Tai Leung (Academia Sinica Phys). Pterostigma on insect locomotion and fluid dynamics of biological sniffers Nonlinear Dynamics (NLD): 6. Evolutionary dynamics and biofilms Sy-Sang Liaw(Physics, NCHU); Jiunn-Ren 7. The evolution of genome Roan (Physics, NCHU); Kai-Jung Chi(Physics, 8. Biological networks and brain NCHU); Ming-Chih Shih(Physics, NCHU); I-Min Tso(Life Science, THU); Jiann-Hwa II. Activities Chen(Molecular Biology, NCHU); Chao-Nien Regular meeting Chen (Math, NCUE); Jeng-Tze Yang (Entomology, NCHU); Ming-Huang Wu (Physics, Seminars: Thursday 12:00-13:00 at NCU (BSM) NCHU) and Tzyy-Leng Horng(Applied Math, This series of seminars are given mostly by FCU). students and some times by PIs. The diverse Systems Biology (SB): research background in this group has led to discussions on topics such as nonequilibrium Hoong-Chien Lee (NCU Systems Biol), Ming- phenomenon in cold liquids, collective behavior Sheng Wang (NCU Systems Biol & Phys), Sun- of bacteria cultures, nonlinear dynamics in fluids, Chong Wang (NCU Systems Biol), Jung-San and mostly recently, because the establishment of Huang (NCU Systems Biol), Li-Ching Wu (NCU a new experimental group on the motile behavior Systems Biol), Hsuan-Cheng Huang (YMU of E. Coli by Prof. Lo, many different aspects of Biomed Info). the biophysics of E. Coli (motors, mutations, and Besides PIs, there are totally about 10 postdocs chemotaxis behavior) were discussed in the and 50 graduate students in our FG. Because the seminars.

Highlights of Programs -›› 138 Colloquiums: Thursday 11:00-12:00 at NCU (SB) This 2-day workshop, the 5th since 2005, features about 10 lecturers, all PIs from the This series of colloquiums are given mostly by Institute of Physics, Academia Sinica, NCU experts in Taiwan and around the world. The Physics and Systems Biology. 40-50 students newest focus in recent talks is the systems (mostly undergraduates, some graduate biological research related to cancer treatment and students, and even a couple of professors) cancer fundamental research. attended this workshop. The talks are Biophysical Journal Club: Thursday 12:00-13:00 introductory, related to the recent research (NCHU) activities of these PIs. The goal is to attract Biophysical Journal Club was initiated in 2004, more young people to the field of biophysics and it has been continued and thriving and systems biology. successfully with the support of this FG. BJC has • Biophysics workshop: Evolutionary Biology – attracted broad attendance from various Observation, Experiment and Mathematical disciplines. The mailing list of BJC continues Models, Hui-Sun Forest Station, Nan-Tou, Oct. growing. About 20 to 40 people attend the Club at 29-Nov. 1 each gathering. Details of the BJC activity We focus on the science of evolutionary subjects can be found at http://140.120.11.15/ dynamics and the related applications in vedio/biophysics/Chinese/journal%20club/ behaviors of biological systems. Four activity.htm prestigious speakers are invited: Dr. Hisashi Group meeting for nonlinear phenomena: Ohtsuki, Dr. Stuart A. West, Dr. Joan E. Friday 10:30-13:00 (NCHU) Strassmann, and Dr. David C. Queller. About Two main topics are under intense discussion 90 audiences attended the workshop. every week. One is granular physics and the other • Bio-soft matter and systems biology days, Jan. the application of fractal to real non-stationary 25-28, 2010 (scheduled). data. The group has made some achievements As the 5th workshop of this kind since 2005, we including two papers published this year. will invite people who work in bio-soft and Workshops systems biology in Taiwan to this 3-day Some of the workshop activities are described workshop, presenting their recent research in the following. work to other colleagues and to graduate students. Besides educational purpose, this • Summer School in Fluid Dynamics, National workshop will also feature discussion sessions Central University, Aug.10-21. that aim at discussing on-going work of the About 30 undergraduate students from PIs. We expect about 25 PIs and 80 students to Mainland China and Taiwan attended this participate this event. As it used to be, there intense school. The topics range from will be intensive and stimulating discussions. elementary fluid mechanics to modern topics in turbulence, nano-fluidic devices, and III. Visitors and International polymeric fluids. Besides getting a chance to Collaborations learn this important (but neglected in main- Many PIs in our FG has international stream courses) field of physics from about 10 collaborations. For example, many scientists have lecturers, and working hard on the homework visited the group led by Prof. H.C. Lee (NCU), problems (about 2-3 questions were assigned together they have generated many high-quality to the students each day), the students also research results. The total number of international benefit much from the fresh learning attitude of visitors in the year 2009 is 21. The following is friends from the other side of the Formosa only a part of recent international collaborations. strait. 1. Physics of Biological surfaces: Chi (NCHU), • NCU Biophysics camp, National Central Shih (NCHU), and Gorb (Kiel Univ, Germany) University, Oct. 10-11 Prof. Chi has invited Prof. S. Gorb, the group

139 ‹‹- Highlights of Programs leader of evolutionary biomaterials group at cardiac myocytes are not correlated at early Kiel University, for a series of biophysics times, but get synchronized as the cultures workshop. Together, they tend to explore the mature. This synchronization can be feasibility of study physical properties of understood by a Kuramoto model with a time- biological surfaces. Prof. Gorb will visit increasing coupling strength. It is found that Taiwan and conduct collaborative pilot studies the growth of the coupling strength between in April 2010. clusters is linear, while the overall wave dynamics of the system is controlled by the 2. Sand flow through a vertical pipe: Liaw passive fibroblast in the system. (NCHU), Liu (NCHU), Shih (NCHU), Matsushita (Chuo Univ, Japan) 2. In H-C Lee (NCU) group: The inverse- symmetry of complete genome is studied, the The initial experimental idea was proposed by results suggest segmental and whole-genome Prof. Matsushita during his previous visit, the inverse duplications are important mechanisms experimental facility was immediately setup in genome growth and evolution, probably and experiments were continued. Many because they are efficient means by which the interesting phenomena were observed and a genome can exploit its double-stranded model capable of simulating the density flow structure to enrich its code-inventory. of the sand in the pipe was established. 3. In Liaw (NCHU) group: A method to calculate 3. Nonequilibrium dynamics of bio-soft matter: the fractal dimensions of the time series from a Chen (NCU), Mikhailov (FHI-MPI, Germany); geometric point of view by evaluating the Chen (NCU), Prost (ESPCI & Curie Inst, turning angles at every point is proposed. The France), and Joanny (Curie Inst, France) method can be applied easily to existing non- A new theoretical framework for the dynamics stationary data abundant in natural, economic, of lipid bilayers that contain ion pumps was and medical sciences. constructed by HY Chen and A.S. Mikhailov, When the vibration amplitude and filling several new instabilities are predicted in a fraction of granular particles in a container are recent preprint. In another research program, appropriately set, the particles will form a HY Chen, J. Prost, and J-F Joanny together compact cluster. An intruder to this cluster of proposed a new theory for the dynamics of identical particles will migrate in a specific actin polymerization under compression. The direction according to its size and mass. A theory explains recent oscillations observed in mechanism is proposed to explain this an experiment carried by the group led by J. phenomenon, which was called in the literature Israelavichili at UCSB. the horizontal Brazil nut effect. 4. Dynamics of cardiac cell culture: Lai (NCU), 4. In Chi (NCHU) group: In the study of spider Chan (Academia Sinica), Osipov (Russia) et al. web mechanics, Prof. Chi, Prof. I-Min Tso and This is a collaboration that began at 2007. Chen-Pan Liao discovered that wind New experiment/theory on the cardiac cell disturbances can affect the structural and cultures have been done, result results are material properties of spider webs. In greater described in the next section. wind the webs are not only stronger but also have reduced wind drag, which can prevent the IV. Highlights of Research Results webs from breakage. Research results mentioned in “international 5. In Shih (NCHU) group: In the study of collaborations” are not listed below. Some other membrane interaction with large molecules, we research results are: found molecules can preferentially participate 1. In Lai (NCU)/Chan (Academia Sinica) group: in membrane domains. This selectivity could Synchronization of heterogeneous systems play an important factor in the subcellular consist of oscillatory and passive elements, localization of molecules which could be such as in cardiac myocytes/fibroblasts critical to its therapeutic outcome or cellular co-cultures, are studied . The beatings of the toxicity.

Highlights of Programs -›› 140 V. Selected Publications especially vulnerable to changes in the [1] Quantitative measure of randomness and relative orientation of H1 and its S1 flank, order for complete genomes, S-G Kong , W-L C-Y Tseng, C-P Yu, and H-C Lee, Euro. Fan, H-D Chen, J. Wigger, A.E. Torda, and Biophys. J. Biophys. Lett., 38, 601, (2009). H-C Lee, Phys. Rev. E, 79, 061911 (2009) [7] 11. Sy-Sang Liaw* and Feng-Yuan Chiu, [2] Surface response of spherical core-shell “Fractal dimensions of time sequences”, structured nanoparticle by optically induced Physica A388, 3100 (2009) . elastic oscillations of soft shell against hard [8] 12. Fei Fang Chung, Sy-Sang Liaw*, and core, S. I. Bastrukov, Pik-Yin Lai, I. V. Chia-Yi Ju, “Brazil nut effect in a rectangular Molodtsova, H. K. Chang, and D.V. Podgainy, plate under horizontal vibration, Granular Surf. Rev. & Lett. 16, p.1~6 (2009). Matter 11, 79 (2009). [3] Granular Gases in Compartmentalized [9] 13. Yunn-Fang Ho, Ming-Huang Wu, Bor- Systems, Pik-Yin Lai, M. Hou, and C. K. Hen Cheng,Yar-Wen Chen, Ming-Chih Shih*. Chan , J. Phys. Soc. Jpn. (invited review) 78, “Lipid-mediated Preferential Localization of 041001-1~9 (2009). Hypericin in Lipid Membranes” Biochem. [4] Synchronization in growing heterogeneous Biophys. Acta 1788, 1287-1295 (2009) media, W. Chen, S. C. Cheng, E. Avalos, O. [10] 14. Liao, C.-P., Chi, K.-J., and I.-M. Tso. Drugova, G. Osipov, Pik-Yin Lai, and C. K. 2009. The effects of wind on trap Chan, Europhys. Lett. 86, 18001-p1~5(2009). architectural and mechanical properties of a [5] Bursting of Neurons induced by inhibitory sit-and-wait predator. Behavioral Ecology, mechanism, Y. S. Chou, Pik-Yin Lai, and C. doi:10.1093/beheco/arp119 (Advance Access K. Chan, Chin. J. Phys., to be published published online on August 18, 2009) [6] Integrity of H1 helix in prion protein revealed by molecular dynamic simulations to be

141 ‹‹- Highlights of Programs Highlights of Programs Condensed Matter Physics

Working Group on Quantum Phenomena in Condensed Matter Physics A. Focus Group on Mesoscopic Physics and Strongly Correlated Systems Coordinator: Chung-Hou Chung (National Chiao Tung University; email: [email protected]), Hsiu-Hau Lin (National Tsing Hua University; email: [email protected]) Committee members: Chon-Saar Chu (National Chiao Tung University), Chang-Ming Ho (Tamkang University), Chung-Der Hu (National Taiwan University), Di-Jing Huang (National Synchrotron Radiation Research Center), Juhn-Jong Lin (National Chiao Tung University), Wen-Chin Wu (National Taiwan Normal University)

I. Brief Description lasting conference series on mesoscopic and spin physics. In addition, we also organized a summer school in August to attract and train interested students into condensed matter physics. An he goal of our focus group is to promote informal workshop CMP2009 to bring in domestic research topics in mesoscopic physics and researchers was also organized in August. strongly correlated electron systems, with These workshops and conferences have particular emphasis on quantum transport, brought in useful techniques in renormalization multiferroic materials, spintronics and group, Green’s function approach to quantum nanostructures. The sign-up members for our focus transport, non-equilibrium approach to quantum group are over 70 and around 1/3 of the members criticality, dynamical properties in spintronics and have been actively participating the group others. Meanwhile, active group memebers build activities. up collaborations with visitors listed below. II. Activities With limited travel supports, we manage to We have organized 8 workshops/miniprograms support 10 graduate students and postdocs to on functional renormalization group, quantum attend international conferences. This channel of transport, spin dynamics in nanostructures and supports is precious for the talented young bloods others, including two joint workshops with and their exposure to the international community APCTP in Korea on the subject of exotic quantum has given them a glimpse about the outside world. condensation and strongly correlated systems in In addition, we hope to attract young talents into low dimensions. condensed matter physics via summer school, workshops/miniprograms and journal clubs. In the coming spring, we have planned two international conferences. The first one is III. Visitors and International co-organized with APCTP (February 2010) on Collaborations multiferroic materials. The second one is the long-

Highlights of Programs -›› 142 We have 1 long-term visitor and 8 short-term Spintronics visitors this year. Chon-Saar Chu continues his long-term Chung-Hou Chung developed collaboration collaboration with Malshukov [Phys. Rev. Lett. with Woelfle at Karlsruhe and Vojta at Yale on the 95, 107203 (2005)] and investigate the general quantum phase transition associated with the theory for spin Hall effects. Focusing upon the Kondo breakdown mechanism. Right now, Dresselhaus-type intrinsic spin-orbit interaction, Chung-Hou is in the exchange program to Yale they look for the symmetry, or asymmetry, working together with Vojta and others. Hsiu-Hau characteristics in two magnetic-field orientations: Lin collaborates with Lee at Pohang on magnetic along and transverse to the stripe [Phys. Rev. B materials and with Hikihara at Hokkaido on 78, 155302]. They also study the interplay graphene and related materials. He also developed between the Rashba and cubic-k Dresselhaus spin- a long-term collaboration with Tang at New orbit interactions and obtain the spin accumulation Hampshire on low dimensional electron systems. and spin polarizations at the edges and in the bulk Chon-Saar Chu continues his long-term as well [Phys. Rev. B 79, 195314 (2009)]. Hsiu- collaboration with Malshukov from Moscow on Hau Lin develops the theory for carrier-mediated spin Hall effects in various geometries. ferromagnetism and collaborates with experimental group in Taiwan [Appl. Phys. Lett. Shun-Jen Cheng starts collaboration with 92, 242501 (2008)] and in Korea [Appl. Phys. Climente in Spain (June-August 2009) via a Lett. 94, 042509 (2009)]. In particular, the non- miniprogram on spin dynamics. Juhn-Jong Lin collinear exchange coupling between multilayers works with visitor Prof. Lien from Vietnam (May is computed theoretically and explains the 2009) on transport in nanostructures. Hsiu-Hau experimental observations extremely well [Phys. Lin and Chung-Hou Chung plan to build a team Rev. B 79, 140412(R) (2009)]. on functional renormalization group and start collaborating with Prof. Honerkamp (Jan 2009) Multiferroic materials from Germany recently. This ongoing Di-Jing Huang and Chung-Yu Mou work on collaboration also leads to interaction with Prof. the experimental and theoretical sides of the Lee at Berkeley and Dr. Wang at MIT, trying to multiferroic materials. Di-Jing Huang’s group apply the same technique to recently discovered reports the unexpected evolution [Phys. Rev. Lett. iron pnictide superconductors. 102, 067601 (2009)], with thermal and magnetic- field (H) variations, of the interrelation between IV. Highlights of Research Results the polarization P, magnetization M, and spiral Quantum transport wave vector Q in CoCr2O4, which has a Chung-Hou Chung collaborates with Woelfle ferrimagnetic conical-spiral magnetic order. In the at Karlsruhe and Vojta at Yale on the quantum related material LiCu2O2, they find a large phase transition associated with the Kondo interchain coupling which suppresses quantum breakdown mechanism [Phys. Rev. Lett 102, fluctuations along spin chains, and a quasi-2D 216803 (2009)]. They apply the nonequilibrium short-range magnetic order prevails at renormalization group (RG) approach to study temperatures above the magnetic transition [Phys. transport of the system and clarify several Rev. Lett. 101, 077205 (2008)]. These important issues concerning quantum criticality observations unravel the fact that the ground state out of equilibrium. Hsiu-Hau Lin and his students of LiCu2O2 possesses long-range 2D-like investigate the conductance through a single incommensurate magnetic order rather than being impurity in carbon nanotubes and find that it a gapped spin liquid as expected from the nature sensitively depends on the impurity strength and of quantum spin-1/2 chains. the bias voltage [Appl. Phys. Lett. 95, 082104 Nanostructures and low dimensional systems (2009)]. The interplay between the current- carrying scattering states and the evanescent Shun-Jen Cheng works on the theory of diluted modes lead to rich phenomena including resonant magnetic semiconductors in nanorod morphology backward scattering, perfect tunneling, and charge [Phys. Rev. B 77, 115310 (2008)] and also accumulations. investigates magnetic anisotropy in magnetic

143 ‹‹- Highlights of Programs colloidal quantum dots doped with transition [3] Huang WM, Tang JM, Lin HH, Power-law metals [Phys. Rev. B 79, 245301 (2009)]. Shun- singularity in the local density of states due to Jen Cheng collaborates with experimental groups the point defect in graphene, PHYSICAL and finds the diamagnetic shifts for different REVIEW B 80, 121404(R) (2009) exciton complexes confined in small InAs [4] Liu CW, Liu S, Kao YJ, et al., Impurity- quantum dots [Phys. Rev. Lett. 101, 267402 Induced Frustration in Correlated Oxides, (2008)]. In addition, the developed theory is PHYSICAL REVIEW LETTERS 102, applied to explain experimental data in 167201 (2009) semiconducting GaN nanorods [Appl. Phys. Lett. [5] Chang RS, Chu CS, Mal'shukov AG, 95, 051905 (2009); Appl. Phys. Lett. 94, 251912 Competing interplay between Rashba and (2009)]. Hsiu-Hau Lin collaborates with Tang at cubic-k Dresselhaus spin-orbit interactions in New Hampshire on the impurity effect in spin-Hall effect, PHYSICAL REVIEW B 79, graphene [Phys. Rev. B 80, 121404(R) (2009)] 195314 (2009) and find an unexpected anomalous scaling in the local density of states. He also collaborates with [6] Chang PY, Lin HH, Conductance through a Jeng at Academia Sinica and Hikihara at single impurity in the metallic zigzag carbon Hokkaido on the correlation effects in graphene nanotube, APPLIED PHYSICS LETTERS nanoribbons [Phys. Rev. B 79, 035405 (2009)]. In 95, 082104 (2009) addition, he studies the spin-wave excitations near [7] Cheng SJ, Magnetic anisotropy in symmetric graphene edges [Phys. Rev. B 78, 161404(R) magnetic colloidal quantum dots doped with (2008)] and finds a novel relativistic few Mn2+ impurities, PHYSICAL REVIEW ferromagnetic magnon without its relativistic B 79, 245301 (2009) partner. [8] You JS, Huang WM, Lin HH, Relativistic The authors of these highlighted works have ferromagnetic magnon at the zigzag edge of been invited to various workshops and graphene, PHYSICAL REVIEW B 78, international conferences. In particular, both 161404 (2008) Chung-Hou Chung and Hsiu-Hau Lin have been [9] Huang SW, Huang DJ, Okamoto J, et al., invited to participate the Low Dimensional Magnetic ground state and transition of a Electron Systems program at Kavli Institute for quantum multiferroic LiCu2O2, PHYSICAL Theoretical Physics in Santa Barbara and REVIEW LETTERS 101, 077205 (2008) presented their work on quantum transport and [10] Chung-Hou Chung, Gergely Zarand, and graphene this year. Peter Woelfle, Two-stage Kondo effect in double quantum dots: Perturbation theory V. Selected Publications and Numerical Renormalization Group [1] Choi YJ, Okamoto J, Huang DJ, et al., analysis, Phys. Rev. B 77, 035120 (2008). Thermally or Magnetically Induced [11] C. D. Hu, Relationship between Polarization Reversal in the Multiferroic ferroelectricity and Dzyaloshinskii-Moriya CoCr2O4, PHYSICAL REVIEW LETTERS interaction in multiferroics and the effect of 102, 067601 (2009) bond-bending, Phys. Rev. B 77, 174418 [2] Chung CH, Le Hur K, Vojta M, et al., (2008). Nonequilibrium Transport at a Dissipative [12] Wang LY, Chu CS, Mal'shukov AG, Quantum Phase Transition, PHYSICAL Asymmetries in intrinsic spin-Hall effect in REVIEW LETTERS 102, 216803 (2009) low in-plane magnetic field, PHYSICAL REVIEW B 78, 155302 (2008)

Highlights of Programs -›› 144 Working Group on Quantum Phenomena in Condensed Matter Physics B. Focus Group on Numerical Methods for Strongly Correlated Physics Coordinator: Ying-Jer Kao (National Taiwan University; email: [email protected]) Committee members: Yong-Chung Chen (Tunghai University), Chung-Hou Chung (Nation Chiao Tung University), Chang-Ming Ho (Tamkang University), Di-Jing Huang (National Synchrotron Radiation Research Center), Jiunn-Yuan Lin (National Chiao Tung University), Chien-Hua Pao (National Chung Cheng University), Horng-Tay Jeng (Academia Sinica), Wen-Chin Wu (National Taiwan Normal University)

I. Brief Description 2. 2009 Condensed Matter Summer School, August 31-September 2, 2009 (Tainan) 3. CMP2009: NCTS Condensed Matter Summer Workshop, September 3-4, 2009 (Tainan) he “Numerical Methods on Strongly Correlated Physics” (NMSCP) is a focus 4. Conference on Computational Physics 2009, group under the Quantum Phenomena in the December 15-19, 2009 (Kaohsiung) Condensed Matter Physics Working Group. It was 5. Workshop on Quantum Information Science formed to provide a platform for condensed matter and Quantum Manybody Physics (Tainan) theorists who are specializing and/or interested in 6. Bi-weekly Meeting of NMSCP Focus Group numerical simulations to facilitate interaction and (Taipei & Hsin-Chu) collaboration. In addition, activities and visitor programs are designed to provide opportunities Activity (1) is a one-day workshop on for researchers to establish international numerical simulations in strongly correlated collaborations. In addition, travel funds are systems, where international speakers and local available to provide financial support to students researchers exchange ideas and establish future and junior researches to attend international collaborations. Activity (2) & (3) are co-organized conferences. An executive committee of ten under the CMP WG. Activity (2) is designed to members from major institutes is formed to educate graduate students to familiarize them with coordinate these activities and oversee the usage necessary techniques. The summer school also of the fund. serves as a platform for students from different universities to interact with each other. Activity In addition to the executive committee, there (3) is the second year of the CMP workshop, are twenty-two active faculty members and twenty where we provide an environment to establish an junior members (postdocs and senior graduate informal workshop among experts. We aim to students). The focus research topics are (1) create a stage where people can concentrate on a Quantum Information Theory Inspired Numerical specific topic in physics for several days with an Methods, (2) Spin Hall Effect, Topological informal atmosphere, so the initiation of Insulators, Multiferroics and Oxides (3) Quantum collaborations can be facilitated. This year’s major Transport in Nanodevices (4) Superconductivity, themes were spin transport and strongly Supersolidity and Magnetism. correlation in ab initio methods. Activity (4), II. Activities CCP2009, is one of the most important international conferences hosted in Taiwan, and During the past one-year period, our focus our focus group helped part of the organization. In group organized or sponsored following activities, addition, we will organize a workshop on 1. Mini-workshop on Numerical Methods in Quantum Information Science and Quantum Strongly Correlated Systems 2009, May 23, Manybody Physics (Activity (5)), following this 2009 (Taipei) conference. Activity (6) focuses on two special

145 ‹‹- Highlights of Programs topics of Quantum Monte Carlo and Real-space Po-Chung Chen and Min-Fong Yang have Renomalization Group. Seminars are held developed one particular entanglement based biweekly in Taipei and Hsin-Chu alternatively numerical method for strongly correlated systems. with participants from institutes in both areas. In In this approach, the variational ground state addition, live webcast is provided for participants wave-function is in the form of tensor product from remote sites. This informal seminar is state. They use 2D iTEBD to optimize the trial intended to motivate junior researchers to identify wave function, and then use TERG to evaluate the and discuss on research topics. More information expectation values. They demonstrate this method can be found at http://sites.google.com/sites/ can reach high accuracy for first-order transition, nmscp. and then use it to study the frustrated spin-dimer model and identify the regime of super-solid III. Visitors and International phase. Hence extend the usability of the method to Collaborations the frustrated models.[1] Chen was invited to give A. Internatonal Visitors: (Dec 09-Nov 09 ) a talk at APCTP Advanced Program on Quantum Condensation in Pohang. Igor Hubert (Simon Frasier U., Canada) Sujit Sarkar (India), Anders Sandvik (Boston U.), Ling Ying-Jer Kao and his coworkers proposed a Wang (Boston U.). method for contracting the tensor network in two dimensions, based on auxiliary tensors B. International Collaborations: accomplishing successive truncations of 8-index 1. Ming-Che Chang (NTNU) + Qian Niu (UT tensors for 2×2 plaquettes into 4-index tensors. Austin) on non-canonical dynamics with Berry The scheme is variational. Test results for the phase effects. quantum phase transition of the transverse-field Ising model confirm that even the smallest 2. Ying-Jer Kao (NTU) + Anders Sandvik possible tensors produce much better results than (Boston), Roger Melko (Waterloo) on the simple product state. Kao was invited to talk numerical approaches based on tensor on Recent trends in Strongly Correlated Systems, networks for frustrated systems. Kalkota, India. 3. Wen-Chin Wu (NTNU) + Igor Herburt (Simon Ming-Che Chang and Min-Fong Yang study Frasier University, Canada) on issues regarding the magnetization for the classical graphene. antiferromagnetic Ising model on the Shastry- 4. Chien-Hua Pao (CCU) + Mark Jarrell Sutherland lattice using the tensor (Louisiana State University) on DCA studies of renormalization-group approach. For a range of BCS-BEC crossover. temperature and coupling constant, they find a single magnetization plateau at one third of the 5. Horng-Tay Jeng (AS) + M. A. van Hove saturation value.[2] (Hong-Kong), Xiao Hu, Toshiya Hikihar (Japan), H. Berger (Switzerland), Z. Hu B. Spin Hall Effect, Topological Insulators, (Germany), and E. W. Plummer (USA). Multiferroics and Oxides 6. Yung-Chung Chen (THU) + Yong-Baek Kim Guang-Yu Guo and coworkers performed ab (Toronto). initio electronic structure calculations for various transition metal impurities in gold, and they reveal 7. Chao-Cheng Kaun (AS) + Hong Guo (McGill) orbital-dependent Kondo effect in Fe impurity in to study the spin transport in nanostructures. Au, demonstrating that the gigantic spin Hall 8. Yu-Cheng Lin (NCCU) + Heiko Rieger effect observed recently in FePt/Au system at (Germany) on entanglement in quenched room temperature is due to resonant skew disordered systems. scattering enhanced by multi-orbital Kondo effect. [3] This paper was selected as a viewpoint in IV. Highlights of Research Results Physics. Spin Hall effect has recently become an A. Quantum Information Theory Inspired issue of intensive interests both theoretically and Numerical Methods experimentally. A fascinating point of this work is

Highlights of Programs -›› 146 that the spin Hall effect is related to the classic cascade of jumps in the order parameter Kondo problem in condensed-matter physics. Guo (supercurrent and superfluid as a function of the was invited to give an invited talk on Ab Initio superfluid velocity for diameters d < 10-15 nm

Studies of Spin Hall Effect, in International and sufficiently low temperatures T < 0.3-0.4 TC.

Workshop on Advances on Spintronic Materials: When approaching TC, the jumps are smoothed Theory and Experiment, Duisburg, Germany, Nov. into step-like but continuous drops. In the 26-28, 2008, in CECAM Workshop on Orbital mesoscopic regime, the quantum-size cascades are Magnetization in Condensed Matter, Lausanne, fully washed out. Below this regime the critical

Switzerland, June 15-17, 2009, and in current density jC exhibits the quantum-size International Workshop on Novel Topological oscillations with pronounced resonant States in Condensed Matter Physics, Hong Kong, enhancements: the smaller the diameter, the more June 21-24, 2009. significant is the enhancement. Thickness fluctuations of real samples will smooth out such Horng-Tay Jeng and his coworkers used ab oscillations into an overall growth of jC with initio calculations to study a variety of subjects, decreasing nanowire diameter. such as ferromagnetism in armchair graphene nanoribbons[4], they show that the inclusion of Shih-Jye Sun considers the substrate coupling mutual repulsions leads to drastic changes and the effect to transport in nanographene ribbon. He ground state turns ferromagnetic in a range of finds that the coupling between the substrate and carrier concentrations. Their ?ndings highlight the the nanographene ribbon increases the conduction crucial importance of the electron-electron of the nanographene ribbon when compared with interaction and its subtle interplay with boundary a non-substrate-coupled nanographene ribbon, topology in graphene nanoribbons. The resultant especially at small coupling; eventually, the large ferromagnetic state with metallic conductivity has coupling suppresses the conduction.[7] potential applications in spintronics at nanoscale. D. Superconductivity, Supersolidity and [4] Magnetism Ming-Che Chang and Min-Fong Yang study Wen-Chin Wu and coworkers have extended the optical signature of topological insulator. The their earlier work to study the spin-polarized axion coupling in topological insulators couples point-contact spectroscopy in electron-doped electric polarization with magnetic field, and cuprate superconductor (EDSC).[8] They consider magnetization with electric field. As a result, the the interplay between the spin polarization and the usual laws of electromagnetic wave propagation AF order in a d-wave superconductor. It is shown are modified. They find that, because of the axion that there exists midgap surface-state contribution coupling, in order to realize the Brewster-angle to the conductance to which Andreev reflections condition, the incident polarization should be are largely modified due to the interplay between rotated away from the plane of incidence. This the exchange field of ferromagnetic metal and the offers a convenient way to determine the axion AF order in EDSC. Low-energy anomalous angle by optical measurement.[5] Chang was conductance enhancement can occur which could invited to talk at IFF Spring school on further test the existence of AF order in EDSC. Spintronics: From GMR to Quantum Information, 2009, Juelich, Germany, and CECAM workshop Yong-Chung Chen and his coworkers use on Orbital Magnetization in Condensed Matter, numerical quantum and variational Monte Carlo 2009, Lausanne, Switzerland. to investigate the interplay between commensurate lock-in and incommensurate supersolid phases of C. Quantum Transport in Nanodevices the hard-core bosons at half-filling with Chao-Cheng Kaun and coworkers study the anisotropic nearest-neighbor hopping and interplay between the transverse discrete modes repulsive interactions on triangular lattice.[9] with a longitudinal supercurrent in a They find that for finite-size systems, there exist a superconducting nanowire.[6] They find the series of jumps between different supersolid superconductor-to-normal transition induced by a phases as the anisotropy parameter is changed. longitudinal superflow of electrons occurs as a The density ordering wave vectors are locked to

147 ‹‹- Highlights of Programs commensurate values and jump between adjacent V. Selected Publications supersolids. In the thermodynamic limit, however, [1] P. Chen, C.-T. Lai, and M.-F. Yang, J. Stat. the magnitude of these jumps vanishes leading to Mech., P10001 (2009). a continuous set of novel incommensurate [2] M. C. Chang, and M. F. Yang, Phys. Rev. B supersolid phases. 79, 104411 (2009). Ying-Jer Kao and coworkers demonstrate that, [3] G. Y. Guo, S. Maekawa, and N. Nagaosa, using the example of Zn-doped La2CuO4, a Phys. Rev. Lett. 102, 036401 (2009). spinless impurity doped into a non-frustrated [4] H. H. Lin et al., Phys. Rev. B 79, 035405 antiferromagnet can induce substantial frustrating (2009). interactions among the spins surrounding it. This counterintuitive result is the key to resolving [5] M. C. Chang, and M. F. Yang, Phys. Rev. B discrepancies between experimental data and 80, 113304 (2009). earlier theories. This mechanism should be [6] M. D. Croitoru et al., Phys. Rev. B 80, 024513 common to other correlated oxides as well.[10] (2009). Kao was invited to talk at “Recent trends in [7] S. J. Sun, J. Phys. Cond. Matt. 21, 235302 Strongly Correlated Systems”, Kalkota, India. (2009). [8] P. M. Chiu, C. S. Liu, and W. C. Wu, Phys. Rev. B 79, 064509 (2009). [9] S. V. Isakov et al., Euro. Phys. Lett. 87, 36002 (2009). [10] C. W. Liu et al., Phys. Rev. Lett. 102, 167201 (2009).

Highlights of Programs -›› 148 Focus Group on Computational Materials Research

Coordinator: Ching Cheng (National Cheng Kung University; email: [email protected]) Committee members: Chun-Ming Chang (National Dong Hwa University), Feng-Chuan Chuang (National Sun Yat Sen University), Guang-Yu Guo (National Chengchi University & National Taiwan University), Hung-Chung Hsueh (Tamkang University), Chao-Cheng Kaun (Academia Sinica), Ming-Hsien Lee (Tamkang University), Min-Hsiung Tsai (National Sun Yat Sen University), Shiow-Fon Tsay (National Sun Yat Sen University)

I. Brief Description HC Hsueh (TKU) for ExcS, FC Chuang (NSYSU) for NM, CM Chang (NDHU) for QMC and CC Kaun(AS) for QT, and another six senior members of the group, i.e. GY Guo (NTU), MH Lee (TKU), TC Leung (CCU), MH Tsai (NSYSU), SF Tsay he primary purpose of this program is to (NSYSU), and C. Cheng (the coordinator of enhance the domestic research capacity in CMRFG, NCKU). The missions of the committee the computational material science based on the are to allocate the budget, to initiate research first-principles quantum mechanical methods activities, to invite the long-term and short-term through promoting interactions and collaborations visitors and to recommend candidates (Ph.D. among local members as well as between local student or junior scientist) to attend international members and international noted scholars, and school, conference, or workshop through the also through attracting outstanding young financial support of CMRFG. researchers into this field. The CMR focus group presently consists of II. Activities more than 50 members, including 40 faculties and The activities supported by CMRFG are listed 14 postdoctors. According to the interests and the according to the following three categories 1) existing expertises of the members, we have workshops for all members 2) schools 3) study- identified four frontiers to concentrate on, i.e. group meetings. calculations of the electronic excited states 1. 7/1-7/3 2009 : 9th Workshop on First- (ExcS), nanomaterials (NM), quantum Monte Principles Computational Materials Physics Carlo methods (QMC), and quantum transport (QT). Study-group meetings initiated by the 7/6-7/10 2009: The 1st Workshop of High- members involved in these four topics become Performance Computing on Nanoscale one of the main backbone activities in promoting Materials Research 2009 collaborations among members as well as 2. 5/16-5/17 2009 : The school on first-principles stimulating new ideas and in-depth discussions. computational materials research -- So are the corresponding leading international introductory level visitors with the held comparable minischools. The Ph.D. students, postdoctors and the junior 6/06-6/07 2009 : The school on first-principles faculty members are encouraged to attend the computational materials research -- relevant international conferences, workshops and introductory level schools. 7/06-7/10 2009 : The school on first-principles The focus group is run by a committee whose computational materials research -- advanced members consists of four coordinators in charge lever of the activities related to the four frontiers, i.e. 12/27 2009: Minischool of LDA+U and GW

149 ‹‹- Highlights of Programs methods (CCU), is held in National Center for High- Performance Computing. The summer, organized 3. 4/17 2009 : QMC study group meeting by T. C. Leung (CCU), is held in NCTS (south). 5/02 2009 : Excited-state study group meeting Both schools include the practical hands-on 5/08 2009 : Nanomaterials study group sessions. The responses from both students and meeting non-specialist researchers are much positive as there are more than one hundred participants in 6/26 2009 : Excited-state study group meeting the spring school and more than fifty participants 7/06 2009 : QMC study group meeting in the summer school. 7/21 2009 : QMC study group meeting • Excited State study group Meeting and Minischool of LDA+U and GW methods 9/11 2009 : Excited-state study group meeting Four study-group meetings are held for the last 11/06 2009 : Excited-state study group meeting eight months. The discussions are mainly on the 11/11 2009 : QMC study group meeting applications of the present available methods, i.e. the GW methods (VASP and Berkeley GW), the 11/20 2009 : Nanomaterials study group Bethe-Salpeter methods (Berkeley GW) and the meeting time-dependent DFT (Turbomol), for the excited- • The 9th Workshop on First-Principles state study of the bulk materials and Computational Materials Physics nanomaterials. This program-wide workshop was held on July • Quantum Monte Carlo study group Meeting 1-3, 2009 in Cheng Ching Lake of Kaohsiung. Four study-group meetings are held for the last The aim of this workshop is to promote eight months. The discussed topics cover 1) interactions and collaborations among local generation of norm-conserving pseudopotentials members. The CMRFG Committee also takes this with the Opium package 2) atomic or molecular opportunity to learn about the general interests of absorption on surfaces using QMC methods 3) the community in order to organize beneficial magnetic moments of small metallic clusters using activities for the members in the future. All QMC methods 4) generation of Wannier functions participants, particularly PhD students and postdoctors, are encouraged to give a talk in this III. Visitors and International workshop. Collaborations • The 1st Workshop of High-Performance Examples of collaborations between CMRFG Computing on Nanoscale Materials Research members are listed as follows : This workshop is also a program-wide one as 1. CM Chang (NDHU), C Cheng (NCKU) and most of the CMRFG members involve more or CM Wei (AS) on the applications of the less in the studies of nanoscale systems. The Quantum Monte Carlo methods. emphasis is especially on the possible combinations of the less CPU time-consuming 2. HT Jeng (AS) , CY. Ren (NKNU) and CS. methods for larger systems with the accurate first- Hsue (NTHU) on the Orbital Ordering in principles methods to identify the crucial transition-metal oxides and developing a mechanisms for the investigated issues. specialized ab initio code for surface problems. • Schools on First-Principles Computational 3. BR Wu (CGU) and TC Leung (CCU) on the Materials Research electronic and optical properties of ribbon under external electric field. To help the newcomers in this field overcome the hurdle in the beginning, both the introductory- 4. GY Guo ( NTU), TC Leung (CCU) and HC level spring school and the advanced-level Hsueh (TKU) on the ab initio study for the summer school on the first-principles excited state of nanomaterials. computational materials research are organized. 5. CC Kaun (AS) and TS Tang (NUU) on the The spring school, lectured by T. C. Leung

Highlights of Programs -›› 150 quantum transport in graphene nanoribbons experts are expected to lead to concrete and and in nanomachines. eminent research results as the pursuit all the time International collaborations are listed as follows : of the NCTS. (1) Excited State study group meetings 1. GY Guo (NTU) and N Nagaosa (Japan) on the intrinsic spin Hall effect. The group explores the applicability of the established codes for the electronic excitation 2. TC Leung (CCU) and CT Chan (HongKong) using the GW, the Bethe-Salpeter and the time- on the optical properties of nanomaterials. dependent DFT methods. Investigations are 3. CM Wei (AS) and N. Drummond (UK) on the applied to the covalent and ionic insulators as well applications of the Quantum Monte Carlo as the nanosystems. Extensions of these studies to methods. optical spectrum and absorption spectrum are also 4. HC Hsueh (TKU) and SG Louie (USA) on the developed. quasiparticle excitations in nanomaterials. (2) Quantum Monte Carlo study-group meetings 5. CC Kaun (AS) and G Hong (Canada) on the To successfully apply the QMC methods to the spin transport in nanostructures systems consisting of the extensive range of the 6. CC Kaun (AS) and FM Peeters (Belgium) on elements in the periodic table, the generation of the interplay of the transverse discrete modes the physical and cpu-time-affordable norm- with a longitudinal supercurrent in a conserving pseudopotentials is explored and superconducting nanowire achieved. The current effort is mainly on the generation of the maximally localized Wannier IV. Highlights of Research Results functions from the DFT calculations in order to construct a much better initial many-body The community of the first-principles wavefunction for the DMC calculations. In the electronic calculations for materials of this mean time, the effect of the exchange and country has flourished in the last few years. The correlation on the magnetic moments of magnetic number of faculty members in the community clusters and the stability of the surface absorption started by less than ten is now reaching forty. The of atoms and simple molecules are also members benefits extremely from the interactions undergoing investigations. through the activities supported by the NCTS. That the members share their individual expertise (3) Nanomaterials study-group meetings within the community without reservation also The major issues of these meetings are to advances the community’s strength as a whole. identify the way in making use of the advantages How these could lead directly to the concrete of the capable but coarser methods together with research results, e.g. journal publications or the accurate first-principles methods to resolve invited talks, is not as straightforward to identify problems in considerably large-size systems. as might have been implied in the performance evaluations required by the funding agency. Not V. Selected Publications to mention that those concrete research results [1] GY Guo, S Maekawa and N Nagaosa, Phys. also benefit mostly from the personal NSC Rev. Lett., 102, 036401 (2009). projects of the members as well as, for some, the joint projects. [2] TW Chen and GY Guo, Phys. Rev. B 79, 125301 (2009). However, for the last eight months, the [3] ZR Xiao and GY Guo, J. Chem. Phys., 130, majority of the members have benefited 214704 (2009). enormously by the study-group meetings of the focused topics supported by the CMRFG which [4] S Ju, TY Cai, and GY Guo, J. Chem. Phys., could not be acquired from other resources 130, 214708 (2009). otherwise. Continuous supports of these meetings [5] ZZ Zhu, JC Zheng, GY Guo, Chem. Phys. with extensions through invitations and potential Lett., 472, p99 (2009). collaborations with the international leading [6] TH Cho, WH Su, TC Leung, W Ren, CT

151 ‹‹- Highlights of Programs Chan, Phys. Rev. B 79, 235123 (2009). [12] Y. H. Chiu, Y. H. Lai, J. H, Ho, D. S. Chuu, [7] J. P. Chou, H. Y. T. Chen, C. R. Hsing, C. M. and M. F. Lin, Phys. Rev. B 77, 045407 Chang, C. Cheng, and C. M. Wei, Phys. Rev. (2008). B 80, 165412 (2009). [13] C. M. Chang, C. Cheng, C. M. Wei, J. Chem. [8] GY Guo, S Murakami, TW Chen, and N Phys., 128, 124710 (2008). Nagaosa, Phys. Rev. Lett., 100, 096401 [14] F.C. Chuang, Chia-Hsiu Hsu, C.-Z. Wang, (2008). and K.-M. Ho, Phys. Rev. B 77 153409 [9] S. Ju and Guo GY, J. Chem. Phys., 129, (2008). 194704 (2008). [15] PA Lin, HT Jeng, and CS Hsue, Phys. Rev. B [10] S. Ju and G. Y. Guo, Appl. Phys. Lett. 92, 77, 085118 (2008). 202504 (2008). [16] CK Yang, Appl. Phys. Lett. 92, 033103 [11] I. J. Wu and G. Y. Guo , Phys. Rev. B 78, (2008). 035447 (2008). [17] C Cheng, Phys. Rev. B 78, 132403 (2008).

Highlights of Programs -›› 152 Highlights of Programs Particles and Fields

Focus Group on Cosmology and Particle Astrophysics

Coordinator: Pisin Chen (National Taiwan University; email: [email protected]) Committee members: Chuan-Hung Chen (National Cheng Kung University), Chao-Qiang Geng (National Tsing Hua Univeristy), W-Y. Pauchy Hwang (National Taiwan University), Wolung Lee (National Taiwan Normal University), Guey-Lin Lin (National Chiao Tung University), Guo-Chin Liu (Tamkang Univeristy), Kin-Wang Ng (Academia Sinica)

Summary • Invitation of short-term foreign visitors to give lectures at summer or winter school • Encouraging and promoting cooperation and/or joint research projects among domestic research s a new comer in NCTS, the Focus Group groups on Cosmology and Particle Astrophysics (FGCPA) has been very active during 2009. For • Training of graduate students and post-docs the weekly activities, it has been divided into three through their attendance of international schools Local Chapters, in Taipei, Hsinchu and Tainan, or visits to foreign research institutes on the respectively, for seminars and working group longer-term basis meetings. We further held Quarterly Meetings in • Invitation of distinguished cosmologists and Taipei, where the June meeting was held jointly particle astrophysicists for 3-month or longer- with the FG on Gravitation, while the December term visits (See the list of potential visitors). meeting will be a Joint Retreat with the FG on • Establishing exchange programs with foreign LHC. The highlight of the first-year activities is research organizations and conducting exchange perhaps the Summer School on Cosmology activities. Targeted sister institutions include organized jointly with the NTU Leung Center for KIPAC (Stanford), KIC (Cambridge), IPMU Cosmology and Particle Astrophysics (LeCosPA). (University of Tokyo), and KIAA (Peking About 150 students from all over Taiwan attended University). this Summer School. When looking back, it is evident that the mutual support between FGCPA In addition to the Core Members, there are and LeCosPA has been instrumental in the build- about 20 professors and researchers, 10 post-docs, up of the very active research of this field in 12 PhD students, 10 Master students participate in Taiwan. this FG. FGCPA has been pursuing the following 5 I. Brief Description research topics jointly with LeCosPA: The goals of FGCPA are as follows. 1. Large Scale Structure of the Universe (LSS): • Organization of summer or winter school to Keiichi Umetzu (organizer) offer short-term CPA courses to students and researchers 2. Baryon Asymmetry of the Universe (BAU): Chao-Qiang Geng (organizer)

153 ‹‹- Highlights of Programs 3. Dark Energy Phenomenology: Je-An Gu Triggered by the intriguing anomalous cosmic (organizer) ray spectrum observed by PAMELA and ATIC detectors, and the new discovery made by 4. Alternative Models for Cosmic Expansion: Sidney et al. (Nature 2008) where, based on Wolung Lee (organizer) the analysis of the dynamics of 300 galaxies, it 5. Cosmic Rays and Neutrinos: Guey-Lin Lin was claimed that the conventional CDM (cold (orgainzer) dark matter) model was in doubt, we organized this mini-workshop to explore their II. Activities implications. 1. Seminars • Mini-Workshop on Extreme Intensity Laser Taipei Chapter: This seminar series is located at and Science, Dec. 2009 NTU and organized by Pauchy It has been suggested since 1990s that the ultra Hwang. It has been holding high intensity fields in lasers and particle seminars every week except accelerators may be a useful tool for the during the Summer. laboratory investigations of astrophysics such Hsinchu Chapter: This bi-weekly seminar series is as the nature of black hole Hawking radiation, located at NTHU/NCTS. It is the plasma wakefield acceleration for the organized jointly by Chao- production of ultra high energy cosmic rays Qiang Geng (NTHU) and Guey- (UHECR), etc. Recently the European Union Lin Lin (NCTU). has funded a new project, ELI (Extreme Light Infrastructure), to build the world’s highest Tainan Chapter: This series is located at NCKU intensity laser. One of its goals is to investigate and organized by Chuan-Hung laboratory astrophysics. This mini-workshop is Chen. organized to explore the possibility of Taiwan- Since there are relatively fewer ELI collaboration. FG members in southern Taiwan, 5. Summer School it was decided that this series is held non-regularly and jointly The First Summer School on Cosmology was with the existing seminar series in jointly organized by FGCPA and LeCosPA and the Physics Department of was held at NTU in June 2009. In order to NCKU. maximize the effectiveness of students’ learning, we decided to use Chinese instead of English as 2. Working Groups the language for all lectures. Several ethnic Among the 5 Working Groups, except that the Chinese international experts in cosmology, BAU WG organized by Chao-Qiang Geng is including Prof. Lizhi Fang (U. Arizona), were conducted in Hsinchu, the rest are in Taipei. Since invited in addition to other experts in Taiwan as the issues involved in the Dark Energy lecturers. About 150 students from all over Taiwan Phenomenology and the Alternative Models for had attended the School. Among them about 60% Cosmic Expansion WGs, it was eventually were graduate students and post-docs, and the decided that the two WGs activities be combined remaining 40% were upper level undergraduate into one, where Je-An Gu is the organizer. students. Students who were admitted to the 3. Joint Retreats School did not have to pay the registration. Their room-and-board for the four-day event was also Our FG has organized two Joint Retreats with fully covered by the School. Many students could the FG on Gravitation led by Hoi-Lay Yu (AS) not believe the generosity of the School and had and with the FG on LHC led by Xiao-Gang He cherished such an unprecedented learning (NTU) in June and December, respectively. opportunity. 4. Workshops 6. Attendance of International Conferences • Mini-Workshop on Dark Matter Crisis, Jan. • A PhD student was sent to the International 2009 Conference on Cosmic Rays (ICRC) in Poland,

Highlights of Programs -›› 154 where he made a presentation. PAMELA anomaly. • Two post-docs attended the 11 th Marcel • Pisin Chen, Guey-Lin Lin and their PhD student Grossmann Conference in Paris in July. Two Feng-Yin Chang (now post-doc at LeCosPA) other post-docs gave presentations at the OCPA collaborate with R. Sydora (U. Alberta, Canada) Conference, Lanzhou. and R. J. Noble (SLAC) on plasma wakefield acceleration for the production of ultra high • Two Master students and one senior undergrad energy cosmic rays. student gave oral presentation on their research at the 2009 CosPA Symposium in Melbourne, 3. Sister Institutions Australia in November. During 2009, three world-renown institutions: • The Coordinator of FGCPA has given plenary KIPAC (Stanford), IPMU (U. Tokyo) and talks at major international conferences ICRANet (Italy) have signed collaboration including the OCPA Conference in Lanzhou MOUs with LeCosPA. Although FGCPA cannot (Aug. 2009), LEI Conference in Romania (Oct. sign such documents with foreign institutions, it is 2009), The 1st Galelio-Xu Guangqi Conference expected to also benefit from such formal in Shanghai (Oct. 2009), Italian-Korean agreements through its close connections with Conference on Relativistic Astrophysics (Nov. LeCosPA. 2009). He also gave seminars at Imperial College London, University of Oxford, VI. Highlights of Research Results University of Cambridge. • ATIC/PAMELA Anomaly from Fermionic Decaying Dark Matter III. Visitors and International Collaborations Two of our FG’s Core Members, Chuan-Hung Chen and Chao Qiang Geng, collaborated and With the very high degree of overlap between proposed to resolve the ATIC/PAMELA anomaly FGCPA and LeCosPA in terms of research topics by allowing the dark matter to be biased towards and members, many international visitors and decaying into leptons. They showed that the collaborations are shared, with benefits to both. observed P/A anomaly can be explained by the 1. Visitors three body decay of the neutral lepton N2 with the 2 17 mass M ≥1.5 TeV and the lifetime 10 s << τ2 Distinguished international visitors include ≤1026 s. One of the advantages of their mechanism Lizhi Fang (U. Arizona), Remo Ruffini (U. Rome is that there are no requirements for the and ICRANet), Joseph Silk (U. of Oxford), degeneracy of masses and unnaturally small Gerard Mourou (ENSTA, Paris), Sergei Bulanov couplings or any other enhancement factors. (JAEA, Kyoto). • Magnetowave Induced Plasma Wakefield 2. International Collaborations Acceleration for Ultra High Energy Cosmic • Collaboration between Ron Adler (Stanford Rays University) and Pisin Chen (NTU), Fabio Pisin Chen, Guey-Lin Lin and their PhD Scardigli (NTU) and Christine Gruber (NTU & student Feng-Yin Chang (now post-doc at Linz U., Austria) on the pre-inflation LeCosPA) collaborate with R. Sydora (U. Alberta, cosmology. Canada) and R. J. Noble (SLAC) on plasma • Collaboration between Pauchy Hwang (NTU) wakefield acceleration for the production of ultra and Sang Pyo Kim (Korea) on nonlinear QED high energy cosmic rays. Through particle-in-cell effects under Schwinger field. (PIC) simulations, they demonstrated the viability 20 • Collaboration between Pisin Chen and Johann of producing UHECR at energies ~10 eV at Rafelski and his students on the quantum astrophysical sites such as the AGNs. Their paper vacuum structure and cosmology. was published in Phys. Rev. Lett. In March 2009, which was further selected as one of the six papers • Continuing collaboration of Chao Qiang Geng in the Physics Highlights section in the April issue and Odintsov (Barcelonia, Spain) and on of Physics Today. particle astrophysics, in particular on the ATIC/

155 ‹‹- Highlights of Programs • New Approach to Testing Dark Energy Models V. Publications by Observations [1] “Constraints on the Phase Plane of the Dark Je-An Gu, Chien-Wen Chen and Pisin Chen Energy Equation of State” Je-An Gu, Chien- proposed a new model-independent method for Wen Chen, Pisin Chen, accepted for testing different dark energy models. They publication in Phys. Lett. B (2009); published three papers on this idea in New J. arXiv:0905.2738. Phys, Mod. Phys. Lett. A, and Phys. Lett. B. In [2] “ATIC/PAMELA anomaly from fermionic particular, they found that dark energy models decaying Dark Matter” Chuan-Hung Chen, including the cosmological constant, phantom, Chao-Qiang Geng, Dmitry V. Zhuridov, Phys. non-phantom barotropic fluids, and monotonic Lett. B675: 77 (2009). up-rolling quintessence are ruled out at the 68.3% [3] “Neutrino Masses, Leptogenesis and confidence level based on the current Decaying Dark Matter” Chuan-Hung Chen, observational data. Down-rolling quintessence, Chao-Qiang Geng, Dmitry V. Zhuridov JCAP including the thawing and the freezing models, is 0910:001 (2009). consistent with the current observations. All the [4] “Resolving Fermi, PAMELA and ATIC above-mentioned models are still consistent with Anomalies in Split Supersymmetry without the data at the 95.4% confidence level. R-Parity” Chuan-Hung Chen, Chao-Qiang Geng, Dmitry V. Zhuridov, Preprint: arXiv:0905.0652 [5] “Resolution to Neutrino Masses, Baryon Asymmetry in Leptogenesis and Cosmic-Ray Anomalies” C. H. Chen, Preprint: arXiv:0905.3425 [6] “Sommerfeld Enhancement from Unparticle Exchange for Dark Matter Annihilation” C.H. Cen and C.S. Kim, Preprint: arXiv:0909.1878

Highlights of Programs -›› 156 Focus Group on Gravitation

Coordinator: Hoi-Lai Yu (Academia Sinica; email: [email protected]) Committee members: Hing-Tong Cho (Tamkang University), Da-Shin Lee (National Dong Hwa University), James M. Nester (National Central University), Chopin Soo (National Cheng Kung University)

I. Brief Description avoid the obstruction in the Parikh–Wilczek derivation of Hawking radiation. Much effort has been focusing on the student training programs which is a unique program of his has been an exciting year for the the Gravitation focus group among other focus gravitation focus group. Let us first groups in the community. More than 15 students highlight some of the developments, beginning were encouraged and supported to participate in with, studies in the stochastic gravity on de Sitter international conference abroad. With the help of spacetime, which have revealed the fluctuation of Prof. Y. K. Lau from The Applied Mathematics the corresponding Hawking radiation. Also, work Institute, Academia Sinica, Beijing, more than 10 on higher-dimensional Kerr black holes has been students each year were able to participate in the focusing on the analysis of the quasinormal modes gravitation related summer school/institute and the emission of particles in the Hawking program hosted by China. We believe this will radiation. The investigation of gravitational help the student not only to expand their energy and gauge theories of gravity, being one of knowledge spectrum and opportunities but also to the main academic activities in our focus group, become more mature at an early stage of their had also gained tremendous momentum and academic careers. important results, especially concerning, theories with torsion, using the covariant Hamiltonian In 2010 our focus should host: International formalism developed by our colleagues in recent Association for Relativistic Dynamics (IARD) years. In particular, they have been looking into 2010. how to choose the quasi-local reference/ 29th May – 1st June, 2010 we shall host the displacement, the energy of cosmologies, and the IARD, and more than 70 distinguished post-Riemannian cosmological effects of gauge Relativitists and gravity related researchers from theories of gravity. Our numerical relativity abroad are expected to participate in the colleagues have improved the flexibility of the IARD2010. FMR/AMR in their code, including the moving- box method, the higher-order 3D Hermite II. Activities interpolation for the interface between different The following major activities were carried out levels of grid. One of the triumphs is to evolve a last year on top of our regular/irregular journal binary black hole from its quasi-circular initial club meetings at the Institute of Physics, data in the in-spiral stage, through the plunge Academia Sinica and Department of Physics at stage, to its final merger and extract the complete National Central University, National Cheng Kung gravitational radiation. In the investigation of and National Dong Hwa University. Lorentz symmetry which is manifested as a local gauge symmetry in curved spacetime, the (1) APCTP-NCTS International School/ generalizations of the Painleve–Gullstrand slicing Workshop on Gravitation and Cosmology, th th which are not spatially flat but remain regular at Pohang, Korea, 16 January-20 ; http:// the horizons have been introduced which can apctp.org/conferences/2009/IWGC2009/

157 ‹‹- Highlights of Programs This was the third joint international school/ Wu) were arranged to visit and conduct workshop of the sort in Cosmology and research at Princeton University, the Gravitation. This time hosted by APCTP and University of Maryland , Tuft University, the co-sponsored by NCTS and Institute of Physics, International Center for Gravitation Research Academia Sinica. The meeting was not only at the University of Pennsylvania and the helpful in reinforcing collaborative research Perimeter Institute, Canada. Several important activities among Asia Pacific area within a flight papers (see the highlights and publication list distance of two hours but also in attracting below) in the cutting edge were published talented young researchers to contribute. The main during these activities. purpose of this meeting is to introduce to students (ii) With the help of Prof. Y.K. Lau, more than 13 and researchers the latest developments in graduate students (from NCU, NDHU and gravitation, semi-classical and quantum gravity. NCKU) were arrange to attend the gravitation We had 16 graduate students, postdocs and 11 workshop at the Institute of Applied local faculties fly to Pohang, Korea to participate Mathematics, Academia Sinica, Beijing and to in the school/workshop. About 35 students/ participate in related research programs (i.e. faculties from the Asia Pacific area, Europe and Summer School at Wuhan, June, 2009) during the United States participated in the meeting. The the summer annually in the last four years. school lectures which were catered to bring to the (iii) Joint School/Workshop in Gravitation in the students the conceptual foundations and technical Asia-Pacific is aimed not only to bring to know-how to the latest development in the researchers the latest developments and to gravitation related areas. promote collaborations but also to bring to the (2) 4 th Sept-5th Sept. Mini-Workshop on graduate students a wide spectrum of Cosmology and Gravitation at Tamkang knowledge and technical know-how at an University early stage of their academic career. The joint meetings will rotate between Taiwan, China, The main purpose of the workshop is for Korea and Japan. The 2011 meeting will be participants to present ideas of on-going and hosted by Shanghai Normal University. future research projects on cosmology and gravitation. It was hoped that this would stimulate (iv) Combine with resources from the Institute of discussions and initiate further collaborations Physics, Academia Sinica, our FG had among participants. successfully brought to the community (3) 29 March, 2009 Mini-workshop on distinguished researchers for long stays (one Gravitation and Cosmology to three months) which had benefited not only our faculties but also graduate students This workshop was organized by colleagues at through seminar, discussions and National Central University during Prof. Friedrich collaborations. Among them are : Hehl’s (University of Cologne) visit to our focus (a) Prof. Larry Ford from Tuft University who group. had triggered works on the instabilities of rd (4) 13 June, Joint Meeting of NCTS FG on De Sitter space through the gauge invariant Gravitation and FGCPA at NTU Ricci tensor. This is the first joint meeting between our FG (b) Prof. Friedrich Hehl from University of and the FGCPA. The main purpose of the meeting Cologne resulted in (1) rekindling an old is to communicate ideas and initiate possible joint research project that will lead to 2 collaborations between our FG and the FGCPA. publications, (2) catalyzing the revision of another of Prof. Nester’s dormant works lll. Visitors and International (now accepted), and (3) generating a new Collaborations line of inquiry into gauge theories of (i) With the help of Profs. L. Ford and B.L. Hu gravity with odd parity terms (drafts of 2 our postdocs (S.Y. Lin, C.S. Chou and C.H. papers now exist).

Highlights of Programs -›› 158 (c) During Dr. Shan Bai's visit in Taiwan, we symmetric metrics by physical Lorentz have developed the code of the initial data boosts. With these generalized PG metrics, in thespectral method in order to simulate problematic contributions to the imaginary the evolution in various scenarios. With the part of the action in the Parikh–Wilczek code we will be able to specify different derivation of Hawking radiation due to the mass ratios, different spin magnitudes, and obstruction can be avoided. Generalized PG coordinate separations once the code is coordinates for stationary axisymmetric completed. Dr. Shan Bai's visit will help the spacetimes are also explicitly constructed; students in their waveform extraction. and the results are applied to the Kerr- Newman family of rotating black hole (d) Dr. ZhouJian Cao has done a lot of solutions. The generalizations are all free of improvement on the various flexibility of coordinate singularities at the horizon(s). the FMR/AMR in our code, including the moving-box method, the higher-order 3D (viii) A general expression for quasilocal energy Hermite interpolation for the interface flux for spacetime perturbation is derived between different levels of grid during his from covariant Hamiltonian formulation visit to Taiwan. using functional differentiability and symplectic structure invariance, which is lV. Highlights of Research Results independent of the choice of the canonical (i) Investigate the gravitational energy within variables and the possible boundary terms small regions of spacetime, one initially puts into the Lagrangian in the diffeomorphism invariant theories. The (ii) Develop normal frames for use in small energy flux expression depends on a regions of spacetime, displacement vector field and the 2-surface (iii) Further develop the Poincare gauge theory under consideration. cosmologies by including the 0- mode, (ix) Have shown that for untrapped or marginal (iv) Improve the various flexibility of the FMR/ surfaces, fixing the area element on the AMR in our code, including the moving-box 2-surface boundary (rather than the induced method, the higher-order 3D Hermite 2-metric) is enough to have a functionally interpolation for the interface between differentiable Hamiltonian. The analysis different levels of grid. provides a natural choice of the evolution vector which reduces to the Kodama vector (v) Evolve a binary black hole from its quasi- in spherical symmetry. This vector plays a circular initial data in the inspiral stage, similar role for the stationary untrapped through the plunge stage, to its final merger. boundary conditions that the stationary During the simulation, we also extract the Killing vector plays for stationary black complete gravitational radiation. The PhD holes. When the vector is null, these student, JuiPing Yu keeps working on the boundary conditions reduce to those given by extraction of the waveform. the isolated horizons. (vi) Developed the code of the initial data in the (x) Have constructed an effective field theory for spectral method in order to simulate the a condensate of cold Fermi atoms whose evolution in various scenarios. With the code scattering is controlled by a narrow Feshbach we will be able to specify different mass resonance. Have shown from first principles, ratios, different spin magnitudes, and it permits a hydrodynamic description of the coordinate separations once the code is BEC-BCS crossover from which the equation completed. of state, intimately related to the speed of (vii) Generalizations of PG slicings which are not sound, can be derived. spatially flat but which remain regular at the (xi) The saturation mechanism of the velocity horizons are introduced. These metrics can be dispersion in a suparohmic environment is obtained from standard spherically found to be distinctly different from that in an

159 ‹‹- Highlights of Programs ohmic environment. The stochastic force [8] J. M. Nester, L. L. So and T. Vargas, “Energy arising from the supraohmic environment is of homogeneous cosmologies” Phys. Rev. D shown to have both positive and negative 78(2008), 044035. correlations, thus leading to the saturation of [9] C. Y. Lin and C. Soo, “Generalized Painleve- the velocity dispersion. Gullstrand Metrics”, Phys. Lett. B671(2009), (xii) The study of the detailed spatial dependence 493. of entanglement dynamics between two [10] R.S. Tung and H. L. Yu, “Quasi-Local Energy Unruh-DeWitt detectors at rest separated in a Flux of Spacetime Perturbation”, Phys. Rev. fixed distance and coupled to a common D78(2008), 104010. relativistic quantum field(This work was [11] R. S. Tung, “Stationary untrapped boundary selected for the May 2009 issue of Virtual conditions in general relativity”, Class. Journal of Quantum Information). Quantum Grav. 25(2008), 085005. [12] R. S. Tung, “Energy and angular momentum V. Publications in strong gravitating systems”, International [1] Hing-Tong Cho, Kin-Wang Ng, and I-Chin Journal of Modern Physics A, 24(2009), Wang, “Scalar field fluctuations in 3538-3544. Schwarzschild-de Sitter space-time”, [13] Y.Y. Charng, D. S. Lee, C.N. Leung, K.W. arXiv:0905.2041 [astro-ph.CO] (2009). Ng, “Affleck-Dine Baryogenesis and [2] Z.J. Cao, H.J. Yo, and J.P. Yu, Phys. Rev. Inflation”, Phys. Rev. D 80(2009), 063519. D78(2008), 124011. [14] C.Y. Lin, D.S. Lee and R. J. Rivers, “The [3] J.M. Nester, “Normal frames for general Non-universal behaviour of Cold Fermi connections” to appear in Ann.Phys. (Berlin), Condensates with Narrow Feshbach 1--8 (2009). Resonances”, Phys.Rev. A 80(2009), [4] H. Chen, F.H. Ho, J.M. Nester, C.H. Wang 043621. and H.J.Yo, “Cosmological dynamics with [15] J.T. Hsiang, T.H. Wu, and D.S. Lee, propagating Lorentz connection modes of spin “Brownian motion of a charged particle zero” J. Cosmology Astroparticle Phys. under electromagnetic fluctuations at finite 10(2009),027. temperature ( to appear in Found. [5] L. L. So and J. M. Nester, “Positive small- Phys.2009). vacuum-region gravitational-energy [16] S.-Y. Lin and B. L. Hu, “Temporal and spatial expressions'' Phys. Rev. D79(2009), 084028. dependence of quantum entanglement from a [6] L. L. So, J. M. Nester, and H. Chen, “Energy- field theory perspective”, Phys. Rev. D momentum density in small regions: the 79(2009), 085020. classical Pseudotensors” Class. Quantum Grav. 26(2009) 085004. [7] L. L. So and J. M. Nester, “Gravitational Energy-Momentum in Small Regions According to the Tetrad-Teleparallel Expressions” Chin. J. Phys. 47(2009), 10.

Highlights of Programs -›› 160 Focus Group on Lattice QCD and Hadron Physics

Coordinator: Ting-Wai Chiu (National Taiwan University; email: [email protected]) Committee members: Jiunn-Wei Chen (National Taiwan University), Chung-Wen Kao (Chung-Yuan Christian University), David Chi-Jen Lin (National Chiao-Tung University), Cheng-Pang Liu (National Dong-Hwa University)

I. Brief Description III. Visitors and International Collaborations The list of visitors can be found from our focus group website (http://phys.cts.ntu.edu.tw/en/) and n LQCD, the scientific goals are (a) the international collaborations can be found from pursuing large-scale unquenched our publication list shown below. The calculations with optimal domain-wall quarks and collaboration between TWQCD and JLQCD, a building up the capacity for large scale computing well known collaboration formed by an elite with the new GPU technology (b) using lattice group of LQCD theorists, was formed since 2006. gauge field theories to explore physics beyond This collaboration has worked out many important standard model. In hadronic physics, the goals are results, with totally 9 papers published in PRL(2), (a) understanding QCD viscosities and their PRD(6), and PLB(1). C.J. David Lin has also relations to phase transitions (b) understanding the formed collaboration with an Oska U. group on impact of box diagrams in radiative corrections to walking technicolor and an Taiwan-UK-US high precision hadronic experiments. (c) collaboration on b-baryon simulations. C.W. Kao Systematic time reversal violation studies of has collaborated with Vanderhaeghen in Mainz; nuclear and atomic systems. C.P. Liu has just come back to Taiwan for one year and has maintained his collaborations with II. Activities many institutes abroad. Lots of activities have been organized to induce new ideas and collaborations: IV. Young Researchers (1) Weekly meetings: In addition to training young researchers with platforms set up by the focus group activities, the (a) Hadron physics at NTU, video focus group has supported Yao-Yuan Mao conferencing with NDHU and NCKU (b) (research assistant) to attend Lattice 2009 (he also TWQCD collaboration at NTU (c) Lattice QCD attended 2009 Les Houches School with full journal club (d) Seminars Series at NDHU support from Les Houches), Kenji Ogawa (biweekly), co-funded by LQCDHP and (postdoc) to visit KEK, and Yen-Fu Liu (Ph. D. Cosmology focus groups student) to visit Prof. Tetsufumi Hirano at (2) Schools and Workshops: University of Tokyo for 2 weeks for collaboration. (a) Nucleon Structure (April 27) (b) The 13th J.W. Chen’s students were admitted to Caltech, Taiwan Nuclear Physics Summer School (June Duke and SUNY for physics Ph. D. programs in 29-July 4) http://phys.cts.ntu.edu.tw/nuclear/2009/ 2009. (c) The 2009 Taipei Workshop on Lattice QCD (December 13-15) http://twqcd09.phys.ntu.edu. V. Highlights of Research Results tw/ . A. Lattice QCD The nuclear summer school has attracted (a) Large-scale simulations of unquenched around 100 participants. lattice QCD with optimal domain-wall quarks:

161 ‹‹- Highlights of Programs The TWQCD collaboration led by Ting-Wai (d) Physics related to the LHC-b program Chiu has made a breakthrough in applying the Chi-Jen David Lin has collaboration with new GPU technology in large scale computing. It colleagues in the US and the UK on the physics is the first group around the world to use a GPU related to the LHC-b program which would allow cluster (with 120 Teraflops peak) to perform large- us to probe the possible right-handed coupling scale LQCD simulations and is one of the three structure in physics beyond the Standard Model. groups (together with RBC/UKQCD, JLQCD) Presently, we already calculated the spectrum of that can perform large scale unquenched baryon containing one b quark and found it simulations of lattice QCD with exact chiral consistent with experiment. Calculations for symmetry. relevant matrix elements are being performed. (b) Theoretical prediction of newly discovered B. QCD viscosities Y(4140) In the last few years, Jiunn-Wei Chen has In 2007, TWQCD published a paper “X(3872) initiated a series of investigations of viscosities in lattice QCD with exact chiral symmetry” [T.W. and phase transitions. His paper “Phase transitions Chiu and T.H. Hsieh, Phys. Lett. B646 (2007) 95]. and perfectness of fluids in weakly coupled real In this paper, they investigated the mass spectrum scalar field theories” [ Jiunn-Wei Chen, Mei of 1^{++} exotic mesons with quark content Huang, Yen-Han Li, Eiji Nakano and Di-Lun (c-cbar-q-qbar), using molecular and diquark- Yang, Phys. Lett. B670:18-21,2008] is selected by antidiquark operators. For (c-cbar-u-ubar) the web of science as one of the highly cited operators, they observed a resonance with mass papers last year. In that paper, the simplest around 3891(17)(21) MeV, which is naturally theoretical model with different kinds of phase identified with X(3872) discovered by Belle in transitions is used to rigorously study the relation 2003. Furthermore, they also predicted a heavier between phase transitions and the perfectness of exotic meson resonance with 1^{++}, with quark fluids. It was found that, for the first time, the content (c-cbar-s-sbar), and mass 4143(19)(25) same behavior observed in all the known systems MeV. (there are more than 30 of them) can be On March 17, 2009, CDF announced the reproduced in a theoretical study. It is a follow up discovery of a new exotic state Y(4140). Since study of another paper supporting that the quark Y(4140) decays into J/Psi(3100) and phi(1020), it and gluons plasma that existed a few microsecond is likely that Y(4140) is the exotic (c-cbar-s-sbar) after the big bang is a near perfect fluid. Their state TWQCD have predicted in 2007! Private result appeared in the 2007 US Nuclear Science communications with CDF revealed that the C Long-Range Plan as part of the near perfect fluid parity of Y(4140) is likely to be positive. If story which was featured as the first one of the confirmed, it will be a big triumph of TWQCD. eight recent accomplishments. (c) New strong interactions at TeV scale C. Extraction of the strangeness of the proton In the last few years, Chi-Jen David Lin has In the last few years, Chung Wen Kao has established collaboration with a Osaka University initiated a series of the extraction of the group of led by Professor Tetsuya Ogoni on strangeness of the proton to include state of the art walking technicolour scenario. It is a popular “box diagram” contributions. In their previous possibility for dynamical electroweak symmetry work “The Two-Photon-Exchange and gamma breaking in which flavour-changing neutral Z-Exchange Corrections to parity-Violating current processes are suppressed naturally Elastic Electron-Proton Scattering’’, Phys. Rev. (dynamically). Presently, many researchers are Lett .99:262001,2007, CWK and collaborators looking for candidate strongly-coupled gauge challenged the widely used approximation of the theories for this scenario, which requires a quasi box diagrams by evaluating directly the two- non-trivial infrared fixed point. From our boson exchange effects in a hadronic model and in simulations, we have evidence that SU(3) gauge a partonic model. Their result shows that the two- theory with 12 flavours develops such a fixed boson exchange effects have complicated point. dependence on the kinematics variables and

Highlights of Programs -›› 162 therefore should not be approximated as a [6] “Mixed Action Effective Field Theory: an constant as previous analysis did. This discovery Addendum”, J.W. Chen, M. Golterman, D. has a wide impact on precision measurements O'Connell and A. Walker-Loud, Phys. Rev. where theoretical radiative corrections are critical D79 (2009) 117502. for data interpretation. They have estimated this [7] “U_A(1) Anomaly in Hot and Dense QCD effect on the extracted value of the proton and the Critical Surface”, J.W. Chen, K. strangeness recently and are finishing up a state of Fukushima, H. Kohyama, K. Ohnishi and U. the art analysis on this quantity. Raha, Phys. Rev. D80 (2009) 054012. [8] “pi-pi Scattering in Twisted Mass Chiral VI. Outlook Perturbation Theory”, M. I. Buchoff, J. W. In addition to continue studying the rich Chen and A. Walker-Loud, Phys. Rev. D79 manifestations of QCD in hadronic matter, an (2009) 074503 emerging theme of this focus group is the study of [9] “Universality of mixed action extrapolation new physics (physics beyond the stand model) formulae”, J.W. Chen, D. O'Connell, A. either directly related to (walking Technicolor, Walker-Loud, JHEP 04, 090 (2009) Higgs-Yukawa systems, AdS/CFT) or complimentary to (time violation and box [10] “Bulk viscosity of a gas of massless pions”, diagrams corrections to low energy precision J.W. Chen, J. Wang, Phys. Rev. C79: 044913 tests) LHC physics. TWQCD’s ability to perform (2009). large-scale simulations of unquenched LQCD [11] “A new scheme for the running coupling with optimal domain-wall quarks is also very constant in gauge theories using Wilson exciting and is expected to produce more state of loops”, E. Bilgici, A. Flachi, E. Itou, M. the art results. Kurachi, C.-J. D. Lin, H. Matsufuru, H. Ohki, T. Onogi, T. Yamazaki, Phys. Rev. D80 VII. Selected Publications (2009) 034507. [1] “Topological Susceptibility to the One-Loop [12] “Bottom hadron mass splittings in the static Order in Chiral Perturbation Theory”, limit from 2+1 flavour lattice QCD”, W. TWQCD Collaboration (Yao-Yuan Mao and Detmold, C.-J. David Lin, M. Wingate, Nucl. Ting-Wai Chiu), Phys. Rev. D80 (2009) Phys. B818 (2009) 17. 034502. [13] “Extraction of charged pion polarizabilities [2] “Topological susceptibility in 2+1 flavors from radiative pion photoproduction in lattice QCD with domain-wall fermions”, Heavy Baryon Chiral perturbation Theory”, TWQCD Collaboration (Ting-Wai Chiu et C.W. Kao, B.E. Norum, K. Wang, Phys. Rev. al.), Phys. Lett. B671 (2009) 135. D79 (2009) 054001. [3] “Lattice calculation of strong coupling [14] “Magnetic susceptibility of QCD vacuum at constant from vacuum polarization functions”, finite density”, S. Nam, H.-Y. Ryu, M. M JLQCD and TWQCD Collaborations (E. Musakhanov, H.-C. Kim , J. Korean Phys. Shintani et al.). Phys. Rev. D79 (2009) Soc. 55 (2009) 429. 074510. [15] “Contribution of Two-Boson-Exchange with Delta(1232) Excitation to Parity-Violating Elastic Electron-Proton Scattering”, K. [4] “Non-perturbative renormalization of bilinear Nagata, H. Q. Zhou, C.W. Kao, S.N. Yang, operators with dynamical overlap fermions”, Phys. Rev. C79 (2009) 062501. JLQCD and TWQCD Collaborations (J. Noaki et al.), arXiv:0907.2751, to appear in Phys. Rev. D (2009). [5] “Pion form factors from two-flavor lattice QCD with exact chiral symmetry”, JLQCD Collaboration and TWQCD Collaboration (S. Aoki et al.), Phys. Rev. D80 (2009) 034508.

163 ‹‹- Highlights of Programs Focus Group on LHC Physics

Cheif coordinator: Xiao-Gang He (National Taiwan University; email:[email protected]) Coordinators: Chuan-Hung Chen (National Cheng Kung University), Kingman Cheung (National Tsing Hua University), Cheng-Wei Chiang (National Central University), Keiw-Chou Yang (Chung-Yuan Christian University), Tzu-Chiang Yuan (Academia Sinica)

I. Brief Description II. Activities To bring all interested researchers to be more coherently involved in related research activities, the focus group is conducting several types of he large hadron collider (LHC) at CERN activities: will be in operation soon. LHC physics a. We have formed natural working group at will become one of the most important fields in different universities AS, CYCU, NCKU, particle physics in the next 10 to 20 years. The NTHU and NTU, involving faculty members purpose of this focus group, the LHC Physics and Postdocs, visitors and students. Seminars Focus Group, is to bring out all the existing are conducted on weekly bases. This year we theoretical efforts, to establish close working have had 109 seminars in total so far. These relations with our experimental groups, and also seminars benefited our researchers and students to train young researchers and students in this area in many ways. to play an important role in this field. Our focuses, as stated in our proposal, are in the following b. Beside local natural working group seminars, directions: we have also set up mechanism to organize special mini-workshops to report new research • Investigation of physics of electroweak results from group members and also symmetry breaking and international visitors, and to have quick • Higgs mechanism response to new discoveries. This year we • Physics beyond the standard model. already had two rapid responding meetings on dark matter and 3 mini-workshops (2 already • Probing the nature of dark matter conducted and another will be held on 12/12). • Flavor physics and CP violation These meetings are held at different university. These activities also enabled our theoretical We formed our coordinator team involving researchers to have more chances to interact active researchers from different universities with with experimentalists. one person as the chief coordinator taking care of details. The current chief coordinator is Xiao- c. We also organize conferences and schools to Gang He. The next five years’ chief coordinators, attract international visitors and to train our in order, are: Tzu-Chiang Yuan (AS), Cheng-Wei young students. This year we organized, as th Chiang (NCU), Keiw-Chou Yang (CYCU), co-organizers, two conferences: the 8 Particle th Chuan-Hung Chen (NCKU) and Kingman Cheung Physics Phenomenology, and the 4 (NTHU). International Symposium on Symmetries in Subatomic Physics. And two schools: the Our members come from all over Taiwan particle physics Spring School, and the summer containing 25 faculties (18 theorists and 7 School. experimentalists), 15 post doctoral fellows, and about 30 master and Ph.D students. d. One of the main purposes of NCTS is to train young-generation physicists. We have made our efforts in this direction. We have used the

Highlights of Programs -›› 164 NCTS multi-year senior visitor program more than one institutes in Taiwan. Our members invited Professors Tony Zee and We-Yi Keung have been invited to give talks at international to visit us and to work with some of our conferences more than 10 times, and also more members and give mini-courses to our graduate than 5 contributed talks. We highlight students. We also used our limited money to achievements according to the topics proposed in support students, postdocs and young faculties reverse order in the following. to attend international conferences to give • Flavor physics and CP violation talks. This year, we will send at least 1 student and 3 postdocs to conferences. We have Taiwan has strong tradition working in the established an international exchange program field of flavor physics and CP violation, in with KEK theory group in Japan. This year we particular in B related flavor physics and CP have sent 4 of our researchers to KEK. violation. Since LHC has LHCb program and also Belle II may well continue in the future, we III. Visitors and International should keep enough efforts in this area. Collaborations Hai-Yang Cheng, Chun-Khiang Chua, Keiw- International collaboration is one of our Chou Yang and their groups have been strengths. Many of our members have concentrate on CP violation in B(Bs) to two international collaborators. We have more than15 mesons and two baryons. They found that some of international collaborations working on topics them to be very sensitive probe of new physics. related to our physics problems from the China, They carried out an updated QCD light cone Europe, Japan, Korea and USA.. calculation of B→Vγ decay and found that their results from their method are in good agreement Using limited resources from our FG budget, with data. we have invited more than 20 international visitors to come to Taiwan to work with our Cheng-Wei Chiang and his collaborators have members. We have used the NCTS multi-year model independent analysis of B to PP and PV senior visitor program invited Professors Tony decays. By performing global fits, they find that Zee and We-Yi Keung to visit us and to work with current data can be satisfactorily explained within some of our members and give mini-courses to the Standard Model (SM). The analysis can our graduate students. provide an independent constraint on the unitarity triangle at a precision level comparable to other We do not limit ourselves just to invite methods. They also found that the famous B to Kπ international collaborator to come to Taiwan for puzzle, using latest data, no longer provides collaborations, we also used our limited money to compelling reasons for the need of new physics. support students, postdocs and faculties to attend Hsiang-nan Li also anlysised K pi puzzle recently. international conferences to give talks aiming at forming new collaborations. This year, we plan to Chuan-Hung Chen, Chao-Qiang Geng and send at least 1 student and 3 postdocs to their group have shown that new physics can conferences. have significant effects on B(B_s) mixing and also on b to q l \bar l. We have established an international exchange program with KEK theory group in Japan. This • Probing the nature of dark matter year we have sent 4 of our researchers to KEK. This year is an exciting year for dark matter study. Last year Pamela and ATIC, and this year IV. Highlights of Research Results FERMI-LAT data show that there are excesses in As a result of our efficient operation, we have cosmic e+ and e-. One of the possible sources for been able to move on to physics problems studies these excesses is from dark matter annihilation or and to stimulate collaborations quickly. We are dark matter decay. Our focus group has responded very pleased to report that we have made rapidly from several fronts, model independent progresses in most areas proposed to study. analysis of dark matter properties, dark matter Among the papers by group members more than decay and annihilation models. Chuan-Hung 20 papers were written with authors come from Chen, Kingman Cheung, Chao-Qiang Geng, Xiao-

165 ‹‹- Highlights of Programs Gang He, Tzu-Chiang Yuan and their groups have Supersymmetry is another very well motivated written, in a short time, 9 papers. Our papers are theory. Recently people have been interested in well cited. We also organized two discussion another way of extending the minimal MSSM by sessions on experimental data and theoretical adding dimension five operator to the theory ideas jointly with Cosmology and Astrophysics without enlarging particle contents. Kingman Focus group. Some of the models proposed may Cheung and his group have studied the impact of be further tested at the LHC. such an extension. They found that it has a • Physics beyond the standard mode and significant impact on the scenario of the Higgsino- *Investigation of physics of electroweak dominated neutralino state being the lightest symmetry breaking and Higgs mechanism supersymmetric particle (LSP). It increases the mass difference between the LSP and the lightest Higgs search is the main goal of the LHC. chargino as well as that between the LSP and the Naturally it is one ofhte focus for our group. second-lightest neutralino and therefore enhances Xiao-Gang He and his group have studied the LHC discovery potential. possible beyond the SM effects which may change LHC offers a possibility to directly test the the SM properties, such as enhanced invisible seesaw mechanism which explains why neutrinos Higgs decay modes from unparticle or dark are so much lighter than their charged partners. In matter. New search strategies may be needed. a series of papers, Xiao-Gang He and his There may be also new types of Higgs particles. collaborators showed that there are new solutions Recently Cheng-Wei Chiang and Akroyd have which can have large mixing providing the hope studied how a doubly charged Higgs boson of the of testing the seesaw mechanism at the LHC. triplet Higgs in Type-II seesaw can be search for They also found that the Type-III seesaw model and studied at hadron colliders. They found that proposed by professor He and his collaborators in there is strong correlation between neutrino mass 1989, can be better tested at the LHC (For more hierarchy and Majorana phase. This work detailed descriptions see the report to NSC). establishes one direct link between LHC physics and the neutrinos. V. Publication Z’ physics. This is a new boson particle We have published 41 SCI papers (18 with resulting from extended gauge groups beyond the NCTS in the addresses and 23 with SM. This is probably one of the most motivated acknowledgment to NCTS), and have written 21 new particles beyond the SM. This year Cheng- preprints submitted to SCI journals for publication Wei Chiang, Kingman Cheung, Xiao-Gang He, (11 with NCTS in the addresses and 10 with Tzu-Chiang Yuan and their groups have attacked acknowledgement to NCTS), and 3 conference related studies from flavor violating, collider proceedings. (See publication list in the report to signature and also model building aspects. We are NSC), The Focus group has allowed us to react working out some of the best ways to search for quickly of new developments. We are confident to such a particle. In a related study, Kingman make even better progresses in the future. We Cheung and Tzu-Chiang Yuan proposed a W' hope to have continued support at the same level. boson that couples to down and top quarks can give rise a large enough forward-backward asymmetry to explain recent CDF data.

Highlights of Programs -›› 166 Focus Group on Strings

Coordinator: Chiang-Mei Chen (National Central University; email: [email protected]) Committee members: Chuan-Tsung Chan (Tung Hai University), Kazuyuki Furuuchi (National Center for Theoretical Sciences), Choon-Lin Ho (Tamkang University),Pei-Ming Ho (National Taiwan University), Hsien-chung Kao (National Taiwan Normal University), Jen-Chi Lee (National Chiao Tung University), Feng-Li Lin (National Taiwan Normal University), Yi Yang (National Chiao Tung University).

I. Brief Description cosmology inspired from string theories. Our progress will be summarized later. Our group also encourages and supports postdocs and students to attend international ur FG in this year includes the following conferences and workshops. In January 2009, we postdocs members: Hirotaka Irie, Hiroshi organized the first international Taiwan String Isono, Tomohisa Takimi, Wen-Yu Wen (Nat’l Theory Workshop focused on the topics of black Taiwan U), Shou-Huang Dai, Pei-Wen Kao, holes physics and the holographic principle. The Shoichi Kawamoto, Chen-Pin Yeh (Nat’l Taiwan second Workshop has been arranged in December Normal U), Dmitry Orlov, Jia-Rui Sun (Nat’l of this year at Taiwan Normal University. We Central U), Takayuki Hirayama, Dan Tomino, hope to keep this workshop annually as a Chih-Wei Wang (NCTS), Keijiro Takahashi, significant event of our FG. This activity can Yoshihiro Mitsuka (Nat’l Chiao Tung U), Wen- advance the visibility of the Taiwan string Tsan Lin (Tamkang U). There are also about nine community. student members. The String FG activities are organized to II. Research Activities enhance the interaction and collaboration among 1. Weekly string seminars at NTU the group members, and to establish intense http://web.phys.ntu.edu.tw/string/index.htm international connections in particular with the Japanese and Korean string communities. The weekly seminars at NTU are a core Following the tremendous efforts of the previous activity of our group initiated in 1996. The coordinators, Pei-Ming Ho, Jen-Chi Lee and schedule is arranged in the Friday afternoon which Hsien-chung Kao, our members have benefited is the most convenient time that our group considerably from the FG activities, such as members can attend. The talks are given either by regular seminars, topic working groups, and group members or by invited visitors from surely from discussions with our reputable overseas to present their recent works. It usually visitors. Form the local/international collaborated lasts for two hours, so that the details of the work publications, the achievements of the String FG is can be explained to some extent and participants obviously appreciable. have enough time to ask questions. After the seminar, members would usually stay for further The research topics of our group members are discussion with the speaker or with one another. primarily in four directions: (i) using the Lie this has been important for generating 3-algebra to investigate the structure of M-theory, collaborations and bonding among the group (ii) analyzing the high energy string scatterings to members. reveal the hidden symmetry in string theories, (iii) exploring the AdS/CFT duality and its application, 2. Biweekly high energy seminar at NTNU in particular to QCD, condensed matter and http://home.phy.ntnu.edu.tw/~highenergy/ superconductor physics, (iv) gravity and

167 ‹‹- Highlights of Programs This series of seminars includes topics such as Moreover, in this year, we improve our cosmology and particle physics so that the group connections with the string communities in Korea members have a chance to interact with physicists and Mainland China. We would like to strengthen from other fields. Many foreign visitors visiting these connections and extend to other Asian NTU also spend a few days in NTNU for giving countries. additional talks or further discussions. A summary of the information about our 3. Biweekly high energy seminar at NTHU visitors from 2005 can be found at http://web. phys.ntu.edu.tw/string/visitors.html. http://phys.cts.nthu.edu.tw/~string/index.html Our faculty and postdocs members in the IV. Highlights of Research Results Hsinchu area are increasing. Regular seminars 1. Lie 3-Algebra and Multiple M2-branes have been arranged since 2007. Our visitors invited by the members there usually stayed at Based on previous substantial progress, Pei- NCTS. Some of other visitors would like to visit Ming and his cooperators from Japan have NCTS for a few days. Moreover, many lectures extended the connection between D-branes in were arranged by Kazuyuki Furuuchi (there are 5 string theory and the multiple membrane theory of lectures this year) on various interesting topics. Bagger-Lambert-Gustavsson (BLG) to its full extent through discoveries of new Lie 3-algebras. 4. Taiwan String Theory Workshop It is a new development in Mathematics as well as http://phys.cts.ntu.edu.tw/string/2009/ in Physics. Their paper [8] is a “highly cited paper” according to ISI Web of Science in the The first international Taiwan String Theory “Essential Science Indicators” database. The Workshop was organized by Kazuyuki Furuuchi, space-time covariant formulation of BLG model Shoichi Kawamoto and Feng-Li Lin on 19 - 21 was explored and a simple model was suggested. January at Taiwan University. The main topics focus on the aspects of black hole, AdS/CFT and 2. High Energy String Scatterings holographic principles. Five invited speakers from The program of investigating the connection Europe, USA, Japan and Korea lectured on between high-energy scattering amplitudes and frontier progress. This has been helpful for our hidden symmetry in string theory is a long term members to discuss with experts on mainstream project from 2003 based on Jen-Chi’s earlier developments. We plan to continue this workshop works in the 90’s. Our FG members have annually. The second workshop has been arranged published about 20 papers on this subject. This on 20 - 23 December at Taiwan Normal research topic generates intense collaborations in University which has been extended to have a 4 which about half of our members are involved. days program, and 9 invited speakers will attend. 3. AdS/CFT Duality and Its Applications III. Visitors and International AdS/CFT correspondence and its possible Collaborations applications to field theories has become a Inviting favorable visitors and collaborators to creditable focused topic in the string community. visit is one principle program of our FG. A At the critical points, notable rescaling dominate part of our budget is spent on this symmetries emerge in various physical problems purpose. In particular, the string focus group has such as in condensed matter, superconductor etc. maintained a steady and close connection with the It is very difficult to calculate non-perturbative Japanese string community. Many of our visitors, aspects in the original field theory. However, the mainly from Japan, come by their own airfare and AdS/CFT correspondence provides a total we only need to support their local expanses. This different approach which allows us to deal with is way we can have about thirty overseas visitors such problems. Many of our members are working each year in the past few years. In addition, many on this subject cooperating with members of other of our members have been invited to visit several NCTS FGs. institutes. A lot of collaborations have been 4. Gravity and Cosmology generated through these academic exchanges.

Highlights of Programs -›› 168 Gravity and cosmology are close related to JHEP 0903:045 (2009) [arXiv:0901.2003 string theories. In particular, investigation of black [hep-th]]. hole physics has motivated many important [9] Chao Wang, Song He, Mei Huang, Qi-.Shu physical ideas, e.g. the holographic principle. It is Yan and Yi Yang, “Scalar Mesons and also expected to be a crucial step toward the glueballs in Dp-Dq hard-wall models,” quantum gravity. Our FG members have e-Print: arXiv:0902.0864 [hep-th]. considered higher curvature corrections on black [10] Hirotaka Irie, “Fractional supersymmetric hole physics and investigate the microscopic Liouville theory and the multi-cut matrix description of black hole entropy. models,” Nucl. Phys. B819 (2009) 351 In the 24 papers done by our FG members, 6 [arXiv:0902.1676 [hep-th]]. papers are international joint work. Moreover, the [11] Kazuyuki Furuuchi and Dan Tomino, working group on little string theory organized by “Supersymmetric reduced models with a Chuan-Tsung Chan starts to produce a paper. symmetry based on Filippov algebra,” JHEP 0905:070 (2009) [arXiv:0902.2041]]. V. Publications [12] Wen-Yu Wen, “Holographic descriptions of [1] Chiang-Mei Chen, Yuan Tsai and Wen-Yu (near-)extremal black holes in five Wen, “Giant Magnons and Spiky Strings on dimensional minimal supergravity,” e-Print: S3 with B-field,” Prog. Theor. Phys. 121, arXiv:0903.4030 [hep-th]. 1189 (2009) [arXiv:0809.3269 [hep-th]]. [13] Chuan-Tsung Chan and Wei-Ming Chen, [2] Feng-Li Lin and Shang-Yu Wu, “Non- “High Energy Symmetry of Bosonic Open relativistic Holography and Singular Black String Theory in the Light-like Linear Hole,” Phys. Lett. B679: 65-72 (2009) Dilaton Background,” accepted by JHEP, [arXiv:0810.0227 [hep-th]]. e-Print: arXiv:0905.2322 [hep-th]. [3] Sheng-Lan Ko, Jen-Chi Lee and Yi Yang, [14] Koji Hashimoto, Takayuki Hirayama and “Kummer function and High Energy String Deog Ki Hong, “Quark Mass Dependence of Scatterings,” e-Print: arXiv:0811.4502 [hep- Hadron Spectrum in Holographic QCD,” th]. e-Print: arXiv:0906.0402 [hep-th]. [4] Takayuki Hirayama and Dan Tomino, [15] Kazuyuki Furuuchi and Tomohisa Takimi, “Membrane scattering from Bagger-Lambert “String solitons in the M5-brane theory,” JHEP 0908:071 (2009) worldvolume with a Nambu-Poisson [arXiv:0812.1866 [hep-th]]. structure and Seiberg-Witten map,” JHEP [5] Sheng-Lan Ko, Jen-Chi Lee and Yi Yang, 0908:050 (2009) [arXiv:0906.3172 [hep-th]]. “Patterns of high energy massive string [16] Chuan-Tsung Chan and Wei-Ming Chen, scatterings in the Regge regime,” JHEP “Massive Vertex Operators and Conformal 0906:028 (2009) [arXiv:0812.4190 [hep-th]]. Algebra of the Bosonic Open String Theory [6] Shoichi Kawamoto, Tsunehide Kuroki and in Flat Space-time,” e-Print: Akitsugu Miwa, “Boundary condition for arXiv:0907.5347 [hep-th]. D-brane from Wilson loop, and gravitational [17] Chuan-Tsung Chan and Wei-Ming Chen, interpretation of eigenvalue in matrix model “Vertex Operators and Scattering Amplitudes in AdS/CFT correspondence,” Phys. Rev. of the Bosonic Open String Theory in the D79:126010 (2009) [arXiv:0812.4229 [hep- Linear Dilaton Background,” e-Print: th]]. arXiv:0907.5472 [hep-th] [7] Chiang-Mei Chen and John E. Wang, [18] Hsien-Chung Kao and Wen-Yu Wen, “Holographic Duals of Black Holes in Five- “Absorption cross section in warped AdS(3) dimensional Minimal Supergravity,” e-Print: black hole revisited,” JHEP 0909:102 (2009) arXiv:0901.0538 [hep-th]. [arXiv:0907.5555 [hep-th]]. [8] Pei-Ming Ho, Yutaka Matsuo and Shotaro [19] Chuan-Tsung Chan, Hirotaka Irie, Sheng-Yu Shiba, “Lorentzian Lie (3-)algebra and Darren Shih and Chi-Hsien Yeh, toroidal compactification of M/string theory,”

169 ‹‹- Highlights of Programs “Macroscopic loop amplitudes in the multi- [22] Pei-Ming Ho and Xue-Yan Lin, “A UV cut two-matrix models,” accepted by Nucl. completion of scalar field theory in arbitrary Phys. B [arXiv:0909.1197 [hep-th]]. even dimensions,” e-Print: arXiv:0910.3287 [20] Jen-Chi Lee, Yi Yang and Sheng-Lan Ko, [hep-th]. “Stirling number identities and high energy [23] Chiang-Mei Chen, Dmitri V. Gal'tsov, string scatterings,” e-Print: arXiv:0909.3894 Nobuyoshi Ohta and Dmitry G. Orlov, [hep-th]. “Global solutions for higher-dimensional [21] Chiang-Mei Chen, Jia-Rui Sun and Shou- stretched small black holes,” e-Print: Jyun Zou, “The RN/CFT Correspondence arXiv:0910.3488 [hep-th]. Revisited,” e-Print: arXiv:0910.2076 [hep- [24] Shoichi Kawamoto and Feng-Li Lin, th]. “Holographic Anyons in the ABJM Theory,” e-Print: arXiv:0910.5536 [hep-th].

Highlights of Programs -›› 170 Highlights of Programs Interdisciplinary Fields

Focus Group on Atomic, Molecular and Optical Physics

Coordinator: Daw-Wei Wang (National Tsing Hua University; email: [email protected]) Committee members: Chung-Hou Cheng (National Chiao Tung University), Ying-Cheng Chen (Academia Sinica), Te-Kuei Fang (Fu-Jen Catholic University), Shin-Chuan Gou (National Changhua University of Education), Jiang-Nan Liu (Fu-Jen Catholic University), Wei-Chi Liu (National Taiwan Normal University), Yi-Wei Liu (National Tsing Hua University), Wen-Chin Wu (National Taiwan Normal University)

I. Brief Description laser, cold atom experiments, and quantum Group size: optics etc. II. Activities Cross-Strait AMO Workshop: ctive faculty members are about 20, In Oct. 2008, we hosted a cross-strait Atomic- including experimentalists. Molecular and Optical Physics Workshop in Goal: National Central University, organized by Tai- Shun Yih. We invited several important theorists 1) To encourage more cooperation between as well as experimentalists in AMO fields from faculty in this community, including mainland China to interchange research results cooperation between theorists and and experiences. It was very successful and experimentalist. therefore will be held again in the Institute of 2) To attract more researchers/ students to join to Physics, Chinese Academy of Science, in Dec. form a stable research environment. 2009. We plan to make it a regular annual meeting so that more interchange or connection can be 3) To enhance the research quality by actively made in the AMO community of Taiwan and cooperating with international frontier Mainland China. researchers. International Workshop: Research direction: In the end of March 2009, we held an (1) Strongly correlated effects in cold atoms/ International Workshop on Ultracold Atoms and molecules, Molecules in National Tsing-Hua University, (2) Dynamical properties of Weakly interacting organized by Daw-Wei Wang. We invited several Bose gases, world-leading-edge theorists and experimental groups to introduce their work on ultracold atoms (3) Atomic structure theory and spectroscopy. and molecules. This includes Eugene Demler Besides these three major subjects, we also (Harvard), John Bohn (JILA), Masahito Ueda partially support researches in high intensity (Tokyo U.), Miguel Cazalilla (DIPS, Spain),

171 ‹‹- Highlights of Programs Tilman Pfau’s group (Stuttgart), H. Nergel’s group join this community. (U. Innsbruck) and Jun Ye’s group (JILA) etc. In the afternoon of 3/27, we had a satellite meeting III. Visitors and International for our local researchers to present their works in cooperation front of our invited speakers and got valuable Visitor in the past year: In the previous year feedback. Most of our speakers also stayed for a (Nov. 2008-Oct. 2009), we invited Prof. Eugene few days longer to interact with other researchers Demler (Harvard), John Bohn (JILA), Masahito or to visit other institutes (NTHU,NCTS, IAMS Ueda (Tokyo U.), Miguel Cazalilla (DIPS, Spain), and NCTU). We believe it was a successful to stay NCTS/NTHU for a few days before or workshop and will continue it. after the International Workshop of ultracold Group-participation of ICTP cold atom atoms/molecules. We had a chance to discuss conference: various directions with local community. We also invited Prof. Guo-zheng Wu from Tsing-Hua U. In May 2009, we organize a group of people (5 (Bejing) as a long term visitor (three months). professors, 2 postdocs, and 4 students) to Prof. Wu is an expert in molecular dynamics and participate the Ultracold atom conference in Raman spectroscopy, and provides two short-term International Center for Theoretical Physics classes about group theory and chaotic dynamics. (ICTP), Trieste, Italy. Our focus group provided In June, we also invited Mr. Pingnan Ma, a financial support for three junior researchers student of Fu-Chun Chang and M. Troyer in Hong (postdocs and junior professor). We also got Kong University. Ma gave a series of lectures connected with Prof. G. Shlyapnikov as well as about worm algorithm in quantum Monte Carlo Prof. E. Demler etc. for deeper discussion. Such method. In Oct., we invited Prof. Makoto Tsubota format can encourage local researchers to share (Osaka City U., Japan), who is a world expert in the same vision and enhance the possible quantum fluids and will collaborate with Prof. collaboration in an advanced topics. Shih-Chuan Gou in NCUE. Besides, we also had a Sending students outside for learning quantum chance to invite Dr. K.-K. Ni (JILA) in Nov. to Monte Carlo method: talk about her pioneering experimental work in In July 2009, we sent two students in NTHU to polar molecules, which has been one of the most go to Hong Kong U. to learn a powerful numerical important subjects in ultracold atom systems. method, quantum Monte Carlo in worm Finally, Dr. Yu-Ju Lin from NIST also visited us algorithm. After three weeks, we could build up and presented her important work of artificial our own code and becomes one of a few groups in gauge field in cold atoms. the world (3-5) to have such world’s fastest QMC International cooperation: D.-W. Wang code to exactly calculate many-particle quantum (NTHU) recently has collaboration with Prof. E. phases of bosonic particles in optical lattice. We Demler (Harvard) on dipolar atoms, with G. are going to have the first quantitative comparison Shyalpnikov (LPTMS) on supersoilid phase in in the world between ab inito calculation and in polar molecules, with Cheng Chin and Pingnan situ experiments (data is from Cheng Chin’s group Ma on the first comparison between QMC and the in U. of Chicago). in situ experiments near quantum phase transition, AMO Summer School: and with prof. S. Das Sarma (UMCP) on fermionic polar molecules. Prof. Chung-Hou th In Sep. 2009, we held the 6 AMO summer Chung (NCTU) has a collaboration with Yong school in Institute of Atomic and Molecular Study, Baek Kim (U. Toronto) on the supersolid phase in organized by Wang-Yao Cheng. This year, besides frustrated system. Prof. T.-K, Fang (FJU) of active researchers in the AMO field, we also collaborates with Prof. T.-N. Chang (USC) in invited several speakers from the AMO-related atomic structure theory. Prof. Shih-Chuan Gou industry to share the potential application of AMO collaborates with Prof. Makoto Tsubota (Osaka knowledge to this society. From students’ City U., Japan) on quantum turbulence in cold feedback, we know that this format worked very atoms. well, and will attract more perspective students to

Highlights of Programs -›› 172 IV. Highlight of Research Results the system size is increased. In the thermodynamic Exotic quantum phases of cold atoms and polar limit, we argue that the supersolid phase will molecules: become a real “ imcommensurate” phase where the ordering wave-vector is an irrational number. In recent years, systems of cold polar Quantum Turbulence in Cold atoms: molecules have been one of the most fast growing subject in cold atoms. D.-W. Wang has formed a Quantum turbulence (QT) in the trapped BEC theoretical group in NTHU to explore various has been addressed in the last few years. Recently, aspects of ultracold polar molecules. Recent S.C. Gou and collaborators have studied the important results include (1) the first theoretical hydrodynamic properties of the trapped BEC by prediction about inter-tube correlation in 1D solving the time-dependent Gross-Pitaevskii (GP) double tube systems [1], (2) the first complete equation [7-9], focusing on the dynamics of quantum phase diagram of multi-tube systems [2], turbulent flow in a 2D trapped BEC. In our recent (3) the first exact pseuso-potential for a general results, we have found that 2D quantum power-law potential in 2D system [3]. More works turbulence in trapped BEC is characterized by the are submitted to Phys. Rev. Lett. but not listed k -5/3 and k -4 scaling laws (where k is the here. wavenumber) rather than the k-5/3-k-3 ones (i.e. the Spinor condensate in optical lattice: well-known Kraichnan-Batchelor theory in 2D classical turbulence). We will then examine the M.-C. Chung and S. Yip (Academia Sinica) hydrodynamic behavior of 2D superflow in have been studying spin-1 Bose gas in optical various systems, including the dipolar BEC, two- lattice, in particular atoms with component BEC, spinor BEC, and the Fermi 23 “antiferromagnetic” interactions such as Na superfulids. [4,5]. Due to the rather peculiar effective spin- Atomic structure and spectroscopy: spin interaction, the spin ordering in such a lattice is very different from ordinary anti-ferromagnets. The efforts of his joint theoretical (T. K. Fang In the absence of magnetization, nematic at Fujen University, his Ph. D. student, J. H. Chen, (quadrupolar) ordering is expected. Phase and T. N. Chang at USC) and experimental (T. S. diagrams at both zero and finite temperatures are Yih and his experimental team at NCU) project constructed. In addition to the nematic phase, focus on the study of multi-electron effect in there are also partially polarized and fully photon-atom interaction. A detailed investigation magnetic phases. To investigate the possibility of on resonance spectra of Ca and Sr for an extended reaching the nematic state, the entropy of the energy region [10] using a B-splined based system is compared with the Bose gas without the complex rotation method was carried out with lattice. It is shown that reaching this exotic state very good agreement between theory and should be relatively easy experimentally. experiment. The publication of this work leads to Supersolid phase in triangular optical lattice: the confirmation of Ph. D. degree of J. H. Chen at Fujen University. The extension of this work to C.H. Chung and collaborators (NCTS visitors) resonance spectra in the presence of external showed via Variational Monte Carlo, Quantum electric field has also been carried out. The Monte Carlo (QMC) and spin-wave theory that preliminary result shows, again, good agreement there exits supersolid phase in the Bose-Hubbard between theory and experiment. In addition, a model with hard-core bosons on the anisotropic joint experimental (T. S. Yih at NCU, his Ph. D. triangular lattice over a wide range of parameter student J. I. Luo and a few others at NSRRC) and space in frustration [6]. The QMC results indicate theoretical (T. N. Chang at USC) investigation on the supersolid ordering wave-vector q is pinned to “column density and temperature effects on certain rational numbers as the frustration is photoionization and photoabsorption spectra” has tunned. Different ordering wave-vectors are led to new physical insight which resolves the separated by series first-order jumps in superfluid long standing difficulty on the disagreement density. The superfluid density as a function of between theory and experiment and also among frustration becomes more and more continuous as number of high precision experiments for the

173 ‹‹- Highlights of Programs extra narrow atomic resonances in He. This work known AMO theorist and is a frequent visitor of is also a part of the Ph. D. project of Mr. J. I. Luo NCTS. Prof. Lin is going to have a long-term at NCU. collaboration with Prof. Tsing-Fu Jiang (NCTU) Developing numerical method for strongly on high intensity laser-atom interaction since interacting bosons: summer 2009. However, since Prof. Lin is not officially associated with Taiwan’s community, we (1) D.-W. Wang and R.-K. Lee developed the first feel it is not appropriate to emphasize his large size numerical methods based on important work here in this year. We expect Prof. Truncated Wigner Approximation to study the Jiang’s collaboration with him will bring fruitful quantum fluctuation effects of many-body results in the next few years for our AMO focus dynamics. Using this method, they submitted group. the first paper in the world to investigate the quantum many-body dynamics of the time-of- V. Selected Publications flight experiment, which is the most important [1] C.-M. Chang, et. al., Phys. Rev. A, 79, 053630 tool in cold atom experiments. (2009) (2) D.-W. Wang and P.-C. Chen sent students to [2] Y.-P. Huang and D.-W. Wang, Phys. Rev. A. Hong Kong U. to learn worm algorithm of 80, 053610 (2009) quantum Monte Carlo calculation, the world’s [3] S.-M. Shih and D.-W. Wang, Phys. Rev. A, most efficient code in large size simulation. 79, 065603 (2009) Their ab inito results can be used to directly compare to the in situ experimental data in [4] M. C. Chung and S. K. Yip, Phys. Rev. A 79, Cheng Chin’s group (U. Chicago), showing 053617 (2009) the world’s first quantitative comparison [5] M. C. Chung and S. K. Yip, arXiv:0904.4110, between theory and experiment in quantum accepted by Phys. Rev. A. many-body physics of cold atoms (paper in [6] S. V. Isakov, et al., Europhys. Lett. 87, 36002 preparation). (2009) (3) D.-W. Wang also collaborate with Pingnan Ma [7] T.-L. Horng, C.-H. Hsueh and S.-C. Gou*, on variational Monte Carlo method, which has Phys. Rev. A 77, 063625 (2008) been applied to the strongly interacting [8] T.-L. Horng, et al., Phys. Rev. A 79, 053619 fermionic system to investigate the important (2009) problem of itinerary ferro-magnetism of [9] T.-L. Horng, et al., Phys. Rev. A 80, 023618 ultracold atoms. (2009) High Intensity laser atom interaction: [10] J. H. Chen, T. K. Fang, C. C. Chu, T.S. Yih Besides of the research work above, there are and T. N. Chang, Phys. Rev. A 80, 042509 also important works by Prof. Chi-Dong lin in (2009) Kansas State University. Prof. Lin is a world-wide

Highlights of Programs -›› 174 Focus Group on Plasma Science

Coordinators: Chio-Zong Cheng (National Cheng Kung University; email: [email protected]) Committee members: Lin-Ni Hau (National Central University), Kwo-Ray Chu (National Tsing Hua University), Ker-Chung Shaing (National Cheng Kung University), Chio-Zong Cheng (National Cheng Kung University)

I. Brief Description 2. Lin I (NCU) 3. Lin-Ni Hau (NCU) 4. Ling-Hsiao Lyu (NCU) oals: 5. Yuh-Ren Lin-Liu (NCU) 6. Kwo-Ray Chu (NTHU) 7. Chwung- Shan Kou (NTHU) 1. Organize an annual Plasma Science Workshop; 8. Tsun-Hsu Chang (NTHU) 2. Organize a summer/winter school to offer short 9. Ker-Chung Leou (NTHU) courses to students and researchers; 10. Ker-Chung Shaing (NCKU) 3. Invite short-term foreign visitors to give lectures in summer/winter school or NCTS 11. Kuan-Ren Chen (NCKU) sponsored or co-sponsored Plasma Science 12. Han-Tzong Su (NCKU) Workshop; 13. Kai-Ti Wang (NCKU) 4. Encourage participation in the Joint 14. Rue-Ron Hsu (NCKU) Conference of Asia Fusion Association and 15. Sunny W. Y. Tam (NCKU) Asia Pacific Plasma Theory Conference (APPTC) to be held in Aomori, Japan in 16. Eiichirou Kawamori (NCKU) October, 2009; 17. Ya-Hui Yang (NCKU) 5. Encourage cooperation and/or joint research 18. Yasutaro Nishimura (NCKU) projects among domestic research groups; 19. Yung-Chiang Lan (NCKU) 6. If the funding is available, we plan to invite Focused Research Topics: distinguished foreign plasma theory The focused research topics include basic researchers for a 3-month or longer term magnetized plasma physics with applications in Taiwan visit; magnetic confinement fusion plasmas and space 7. If the funding is available, we plan to establish plasmas. and conduct exchange programs with distinguished foreign plasma research II. Activities organizations. A. We organized the 2009 Plasma Science Names of Coordinators: Summer School, which was held at National Chio-Zong Cheng Cheng Kung University during Aug. 24-28, 2009. In total, 17 lecturers, who are experts on Names of Group Committee Members or Key different plasma science area, are invited from Members: Academia Sinica, National Central University The following list is in alphabetic order of first (NCU), National Chung Cheng University name. (CCU), and National Cheng Kung University (NCKU) to give lectures in the school. The 1. Chin-Ching Tzeng (INER - Institute of Nuclear lectures provide overviews of the major Energy Research) applications of plasma science and technology

175 ‹‹- Highlights of Programs to undergraduate and graduate students who USA): Dr. Nikolai Gorelenkov of Princeton show interest in this field. Four research Plasma Physics laboratory will visit NCKU assistants of Academia Sinica and National during Nov. 29, 2009 – Jan. 1, 2010 to Tsing Hua University (NTHU) and 45 students collaborate on energetic particle physics in from NCU, NTHU, CCU, NTU, and NCKU tokamak plasmas with Prof. C. Z. Cheng and participated in this summer school. About 20 the faculty and staff of Plasma and Space students also presented poster papers to Science Center, NCKU. Dr. Gorelenkov is a discuss and exchange their research results and world-leading theoretist in tokamak fusion ideas with other students and invited lecturers. plasmas with expertise on (1) the stability of Toroidal Alfven Eigenmodes (TAEs), B. The 2009 International Workshop on Frontiers Compressional Alfven Eigenmodes (CAEs), In Space and Fusion Energy Sciences and other Afven eigenmodes in tokamaks; (2) (FISFES), which is co-sponsored by NCTS, the stability of ballooning modes; and (3) will be held at NCKU during Nov. 30 – Dec. 3, kinetic-MHD model of magnetized plasmas. 2009. There will be 52 oral paper presentations Dr. Gorelenkov will also attend the 2009 and 25 poster papers. Experts in space plasma FISFES Workshop to give an invited talk. He and fusion sciences around the world will will also interact with research staff and gather in Taiwan and 32 world-leading plasma students at NCKU. Because of limited budget experts from foreign institutions will attend the of the Plasma Focus Group in 2009 from workshop and give invited talks. It is a great NCTS we provide Dr. Gorelenkov with a very opportunity for our young scientists and small partial support of his housing expense students to learn new trends in frontiers of by using the NCTS fund. space and fusion plasma sciences and technologies and exchange ideas with these B. Professor Kuei-Jen Lee (professor of scholars. In total, about 70 scientists and 30 Department of Communication Engineering in students have registered to attend this event. Oriental Institute of Technology): Prof. Lee was invited as a domestic visitor during the C. The biweekly seminars and meetings on winter vacation in 2009. Prof. Lee is an expert “Subwavelength photonics with nano- on simulation and designing of optical devices, structured plasmonic metamaterials” were photonic crystal simulation, etc. During the organized by Prof. Kuan-Ren Chen. visit, she started the collaborative work of the Subwavelength photonics is a research area of near-field characterization by subwavelength multi-disciplines, involving physics, electro- plasmonic double slits with Professor K. R. optics, materials, mechanical, chemical Chen, Professor K. Y. Kim and Mr. J. S. Hong. engineering and many other disciplinary. After the visit, they presented two papers Currently, the active participants include seven entitled ‘Near-field characterization on light NCKU professors and their students under the interference formed by subwavelength above mentioned disciplines. External and plasmonic double slit of finite length using 3D internal speakers are invited with topics FDTD method’ and ‘Near-field including nanoimprinting, field enhancement characterization on light emanated from in metal nanoparticle arrays, subwavelength subwavelength plasmonic double slits’ in the focusing, nano-structure fabrication, etc. 4th International Conference on Besides the benefits of introducing new fields Electromagnetic Near Field Characterization and new techniques that the routine seminars and Imaging (ICONIC 2009), Taipei, Taiwan. and meeting brought, they also provide an opportunity for the collaborators to meet and discuss with each other. IV. Highlights of Research Results Because the NCTS headquarter informed us to III. Visitors and International use the very limited budget of the Plasma Focus Collaborations Group (about NT$ 90,000 out of NT$600,000 total budget) to support the Sub-wavelength A. Nokolai Gorelenkov (Princeton Plasma photonics research activity led by Prof. Kuan-Ren Physics laboratory, Princeton University,

Highlights of Programs -›› 176 Chen, we have only NT$480,000 left to conduct to attend the 2009 Fall AGU meeting, which is our main focused plasma science activity. We held at San Francisco during Dec. 14-18, 2009. have concentrated our activity in organizing a Dr. Marty Chou will present a paper on “Modeling plasma science summer school and an of Saturn’s magnetosphere based on satellite international workshop on space and fusion observation data.” Dr. Marty Chou is also in the plasma sciences. We have also established process of completing a paper on “Equilibrium collaboration with Dr. Nikolai Gorelenkov of model for Saturn’s magnetosphere” for Princeton Plasma Physics Laboratory, who will submission to J. Geophysical Research in visit Taiwan during Nov. 29, 2009 – Jan. 1, 2010 November, 2009. to collaborate on theory of energetic particles in tokamak fusion plasmas, and we will use NCTS V. Publication fund to provide partial support of the housing [1]. M. Chou and C. Z. Cheng, A 2D equilibrium expense for Dr. Gorelenkov. We also plan to model for Saturn’s magnetosphere, to be provide NCTS foreign travel fund to support Dr. submitted to J. Geophys. Res. (2009). Marty Chou, an NSC postdoc stationed at NCKU,

177 ‹‹- Highlights of Programs Focus Group on Quantum Information Science

Coordinators: Yueh-Nan Chen (National Cheng Kung University; email: [email protected]) Hsi-Sheng Goan (National Taiwan University; email: [email protected]) Committee members: Alec Maassen van den Brink (Academia Sinica), Yia-Chung Chang (Academia Sinica), Pochung Chen (National Tsing Huan University), Chi-Yee Cheung (Academia Sinica), Chung-Hsien Chou (National Cheng Kung University), Li-Yi Hsu (Chung-Yuan Christian University), Chopin Soo (National Cheng Kung University), Zheng-Yao Su (National Center for High-Performance Computing), Wei-Min Zhang (National Cheng Kung University)

I. Brief Description is an emerging research and education frontier that has generated a great deal of interests and stimulated novel potential applications for the last decade. The 4th workshop on QST brought he main mission of the QIS focus group is together both theorists and experimentalists in to build a platform of communication and this area to give lectures and present their discussion for researchers in this area in Taiwan. recent findings. One of the major aims was to In the last few years, we have brought QIS promote and enhance research activities, researchers in Taiwan to work and discuss interactions and collaborations among the research together and to hold activities, such as participants. scientific seminars, workshops and short-term 2. To enhance the international visibility, we schools. We have also been seeking to establish participate in organizing "Conference on links and exchanges as well as to initiate Computational Physics 2009" in Kaohsiung collaborations with other QIS researchers during Dec. 15 ~ 19, 2009. There will be two worldwide. sessions for Quantum Information Science. Focused research topics: High-profile foreign researchers in this field, Prof. J. I. Cirac, Prof. R. Fazio, Prof. G. Vida, Quantum Decoherence, Quantum Prof. A. P. Young and Prof. H. Q. Lin, will give Measurement, Quantum Entanglement, Quantum lectures not only in the conference, but also in Computation and Quantum Communication. the following workshop to be held from Dec. 19 ~ 20, 2009 at NCKU. Therefore, it is II. Activities and Beneficiaries expected to attract many participants, including • Activities faculties, postdocs, and students. 1. “The 4th Workshop on Quantum Science and 3. The workshop in December is jointly organized Technology” at Taichung, Sep. 9 ~ 11 (2009). by two focus groups: QIS focus group and 2. Workshop on Quantum Information Science NMSCP focus group. The aim of this and Many-Body Physics, NCKU, Dec. 19 ~ 20 workshop is to bring together researchers from (2009). quantum information science and quantum many-body physics, to discuss recent advances 3. Mini-workshops and seminars at NCKU, NTU, in quantum many-body systems from the and CYCU. perspectives of quantum information science. It • Beneficiaries is expected that new ideas can be generated via such an interdisciplinary activity. 1. The Quantum Science and Technology (QST) • Training of young-generation physicists

Highlights of Programs -›› 178 1. Financial supports for international Prof. Yan (Hong-Kong) and Prof. Jin conferences (Hangzhou) Projects or Activities: (1) Mrs. Nien-En Wang (NCKU), Chung-Chin Transient quantum transport problems in Jian (NTU) and Shang-Yu Huang (NTU). nanoscale devices. The 3rd Int. Workshop on Solid-State Quantum Computing & Hong Kong Forum QIS members: Prof. C. Y. Cheung on Quantum Control Collaborators: Prof. Zhang (Anhui) (2) Supports students to attend the conference Projects or Activities: CCP2009 in Kaohsiung. Quantum teleportation. III. Visitors and International QIS members: Prof. L. Y. Hsu Collaborations Collaborators: • Visitors Dr. Hsieh (Japan) Projects or Activities: 1. Prof. B. L. Hu, Univ. of Maryland, USA (June Entanglement in entanglement-assisted 2009) quantum low-density parity-check codes. 2. Dr. Mintert, Universitat Freiburg (Sep. 17, QIS members: Prof. L. Y. Hsu 2009 ~Sep. 25, 2009) Collaborators: 3. Dr. D. E. Chang, California Institute of Prof. Long (Beijing) Technology, USA (Feb. 11 ~19, 2009) Projects or Activities: Quantum secret-sharing protocol. 4. Prof. Makhlin, Landau Institute for Theoretical Physics, Russia (Feb. 12, 2009 ~Feb. 14, 2009) QIS members: Prof. C. H. Chou and Prof. Y. N. Chen 5. Prof. Cabello, Universidad de Sevilla, Spain Collaborators: (Feb. 12, 2009 ~Feb. 14, 2009) Prof. Buchleitner (Freiburg) 6. Dr. Lambert, Riken, Japan (Feb. 9, 2009 ~ Feb. Projects or Activities: 15, 2009) (1) Research Visit: Prof. Chou and Prof. Chen visited Freiburg (July 2009). Dr. Mintert 7. Prof. X.Z. Yuan, Shanghai Jiao Tong visited NCKU (Sep. 2009). University, China (Jul. 28, 2009~ Sep. 5, (2) Mr. G. Y. Chen (student to Prof. Y. N. 2009) Chen) visited Freiburg for one year. • International Collaborations QIS members: Prof. Y. N. Chen QIS members: Prof. W. M. Zhang Collaborators: Collaborators: Prof. Nori and Dr. Lambert (Riken) Prof. Aharony and Prof. Entin-Wohlman Projects or Activities: (Isarel) Research visiting: Prof. Y. N. Chen and Dr. Projects or Activities: Lambert. Focus on Quantum measurement. Dephasing problem in quantum transport and QIS members: Prof. H.-S. Goan molecular electronics. Collaborators: QIS members: Prof. W. M. Zhang Prof. X.Z. Yuan and Prof. K. D. Zhu (Shanghai Collaborators: Jiao Tong U.) Prof. Gurvitz (Isarel) and Prof. Li (Beijing) Projects or Activities: Projects or Activities: Research visit: Prof. X.Z. Yuan visited NTU Magnetic field switching in parallel quantum (August 2009) dots and related problems. QIS members: Prof. W. M. Zhang IV. Highlights of Research Results Collaborators: • Research results

179 ‹‹- Highlights of Programs I. Decoherence and Measurements 2. Entanglement dynamics in relativistic motions and macroscopic quantum 1.  Mon-Markovian decoherence theory for phenomena double-dot charge qubit: In the work[10] collaborated with Dr. S.Y. Lin We developed a non-perturbation theory for at NCTS and Prof. B.L. Hu of UMD, we describing non-markovian decoherence started to study the entanglement dynamics of dynamics of electrons in nanoscale devices. We two harmonic oscillators coupled to a extended the Feynman-Vernon influence background field with one in uniform functional theory to fermionic environments acceleration. This is an important ingredient and derive an exact master equation for the for the establishment of relativistic quantum reduced density matrix of electrons in the information theory. In our nonperturbative double dot for a general spectral density at treatment, the field will be evolving with the arbitrary temperature and bias. This should be detectors as a combined close system. a big breakthrough since Hu and co-workers in Maryland Univ derived the first exact master III. Quantum Computation and Quantum equation for quantum Brownian motion Communication (bosonic environment) in 1992 after Feynman 1. Optimal control of quantum gates for and Vernon proposed the influence functional quantum computation theory in 1963. [1]. We apply the gradient ascent pulse engineering 2. Detecting non-Markovian plasmonic band (GRAPE) optimization approach to find gaps in quantum dots using electron control parameter sequence in near time- transport optimal way for a high-fidelity controlled-NOT We show how two non-Markovian effects, (CNOT) gate in silicon-based donor spin band edge and retardation, could be observed quantum computer architectures. This CNOT in such a system. Combined with a quantum- gate has an error of about 10-6, below the error dot p-i-n junction, these effects could be threshold required for fault-tolerant quantum readout via current-noise measurements. We computation, and its operation time of 100ns is also discuss how these effects can occur in about 3 times faster than 297ns of the proposed similar systems with restricted geometries, global control scheme. It also relaxes such as phononic cavities and photonic crystal significantly the stringent distance constraint of waveguides. This work links two previously two neighboring donor atoms of 10~20nm separate topics: surface plasmons and current- reported in the original Kane's proposal to noise measurements. [6] ~30nm in which surface control gates may be II. Quantum Entanglement built with current fabrication technology. [11] 2. Criterion for faithful teleportation with an 1. Field Induced Spin Supersolidity in arbitrary multiparticle channel Frustrated Spin-1/2 Spin-Dimer Models: We present a general criterion which allows We have developed one particular one to judge if an arbitrary multiparticle entanglement based numerical method for entanglement channel can be used to teleport strongly correlated systems. In this approach, faithfully an unknown quantum state of a given the variational ground state wave-function is in dimension. We also present a general the form of tensor product state. We use 2D multiparticle protocol applicable for all iTEBD to optimize the trial wave-fucntion, channel states satisfying this criterion. [14] then use TERG to evaluate the expectation values. We first demonstrated that the method 3. Deterministic dense coding and faithful can reach high accuracy for first-order teleportation with graph states transition. We then use it to study the frustrated We propose schemes to perform the many-to- spin-dimer model and identify the regime of one deterministic dense coding and one-to- super-solid phase. Hence extend the usability many faithful teleportation with multipartite of the method to the frustrated models. [8]

Highlights of Programs -›› 180 graph states. The sufficient and necessary V. Publications condition of a viable graph state can be stated [1] Matisse W. Y. Tu and Wei-Min Zhang, Phys. as follows. For the associated graph, the Rev. B 78, 235311 (2008). reduced adjacency matrix of the Tanner-type [2] Feng Li, Xin-Qi Li, Wei-Min Zhang, S.A. subgraph between senders and receivers should Gurvitz, (EPL, 2009, in press). be invertible. Out results can be generalized to any stabilizer state, which is local equivalent to [3] Matisse W. Y. Tu, M. T. Lee, Wei-Min Zhang, some graph state. [16] Quantum Inf. Process, 8, 631 (2009). [4] J. H. An, M. Feng and Wei-Min Zhang, 4. Quantum direct communication with mutual Quantum Infom. Comput. 9, 0317 (2009). authentication [5] N. Lambert, Y. N. Chen, R. Johansson, F. We propose a new protocol capable of Nori, Phys. Rev. B 80, 165308 (2009). achieving secure quantum direct [6] Y. N. Chen, G. Y. Chen, Y. Y. Liao, N. communication with authentication. Our Lambert, and F. Nori, Phys. Rev. B 79, protocol does not require a direct quantum link 245312 (2009). between any two users, who want to communicate with each other. This may be an [7] Y. N. Chen, G. Y. Chen, D. S. Chuu, and T. appealing advantage in the implementation of a Brandes, Phys. Rev. A 79, 033815 (2009). practical quantum communication network. [8] Pochung Chen, Chen-Yen Lai, and Min-Fong [17] Yang, arXiv:0910.5081. • Invited presentations [9] C. M. Chang, C. Y. Lai, W. C. Shen, Pochung Chen, and D. W. Wang, Phys. Rev. A 79, 1. Prof. C. H. Chou (July 14, 2009) and Prof. Y. 053630 (2009). N. Chen (July 16, 2009), Science seminars at [10] S. Y. Lin, C. H. Chou, and B. L. Hu, Phys. Universitat Freiburg. Rev. D 78, 125025(2008). 2. Prof. W. Zhang, Prof. C. H. Chou and Prof. [11] D.-B. Tsai, P.-W. Chen, and H.-S. Goan, H.-S. Goan, August (2009), The 6th joint Phys. Rev. A 79, 060306 (R) (2009). meeting of Chinese physicists worldwide, [12] Md. M. Ali and H.-S. Goan, J. Phys. A 42, Lanzhou, China 385303 (2009). 3. Prof. W. Zhang and Prof. H.-S. Goan, [13] W. Zhang, Y.M. Liu, Z.J. Zhang, C.Y. December (2009), The 3th International Cheung, Accepted by Optics Communi. Workshop on Solid-State Quantum Computing, (2009). Hong Kong. [14] C.Y. Cheung and Z.J. Zhang, Phys. Rev. A 80, 022327 (2009). [15] C.Y. Huang, I. C. Yu, F. L. Lin, and L. Y. Hsu, Phys. Rev. A 79, 052306 (2009). [16] Li-Yi Hsu and Keng-Shuo Wu, Phys. Rev. A 80, 042324 (2009). [17] C.-A. Yen, S.-J. Horng, H.-S. Goan, T.-W. Kao, Y.-H. Chou, Quantum Infom. Comput. 9, 0376 (2009).

181 ‹‹- Highlights of Programs Highlights of Programs

Topic Program on Laser/Maser Plasma Science

Coordinator: Shih-Hung Chen (National Central University; email: [email protected] ) Committee members: Kwo-Ray Chu (National Tsing Hua University), Wei-Cheng Huang (National Central for High-Performance Computing), Yu-Ren Linliu (National Central University), Ling-Hsiao Lyu (National Central University), You-Hsien Shiau (National Chengchi University), Gih-Yih Tsaur (Tunghai University), Jyhpyng Wang (Academia Sinica)

I. Brief Description been resulted in great advancements. The recent investigations conducted in NTHU group also awake a general interest on a relatively dormant subject, gyrotron backward wave oscillator (gyro- he Laser/Maser Plasma Science Topical BWO). Program is coordinated by Prof. Shih- Facilitated by these two groups, a “theoretical Hung Chen from National Central University. The study and simulation group” which has intensive program plays a major role to integrate the related collaborations with the two groups is forming. The theoretical research and training activities of two new group comprises participants from several research groups, whose research topics include the research institutions and universities. The laser plasma physics and relativistic electronics. operations of this group are concordant with the The first group, High-Field Physics and goals and vision of the NCTS program. Over the Ultrafast Technology Laboratory at the Institute of past few years, the group has built capacities of Atomic and Molecular Sciences, Academia Sinica, the theoretical analysis and the large-scale constructed a high-quality 10-terawatt laser simulation for the study of the laser/maser plasma system in 2004 and complete the construction of a science. The forming of the topical program can 100-TW laser at National Central University by provide a more solid foundation and operation the end of 2007. They utilized the laser facility to mechanism for the theoretical and simulation conduct pioneering experiments in high-field group. science. These three groups represent the local The second group, High Frequency community of laser/maser plasma science, and Electromagnetic Laboratory at National Tsing Hua they have gained lots of scientific achievements of University, has been devoted to the study of the the international visibility. The proposed laser/ Electron Cyclotron Maser during the past twenty maser plasma science topical program intends to years. They have taken the lead in the establish a plateform to serve the community and international microwave/plasma community by to couple all sub-areas through common interest in addressing these physics groundwork that have simulation, theory and education, and to interact with experimentalists under the support of NCTS.

Highlights of Programs -›› 182 The key members include Prof. Kwo Ray Chu supplementary training activity, which fills the (National Tsing Hua University), Prof. Yu-Ren gap left by the cancellation of the original summer Linliu (National Central University), Prof. school in the year, for the topical program. During Jyhpyng Wang (IAMS, Academia Sinica), Prof. the summer school, we also invited Prof. Zeng- Gin-Yih Tsaur (Tunghai University), Ling-Hsiao Ming Sheng (Shanghai Jiao Tong University, P. R. Lyu (National Central University), Weicheng China) to visit National Central University and Huang (Ntl. Center for High-performance discuss about the recnet progresses of the Computing) and Prof. You- Hsien Shiau (National computational study of the laser-based proton Chengchi University). There are 11 researchers/ accelerators with him. professors, 2 post doctors, 10 Ph.D. students and The other important activity is 2009 Plasma 17 Master students joined in the program. Science Summer School held by Plasma and The laser/maser plasma physics is the area to Space Science Center, National Cheng Kung study the highly nonlinear and highly relativistic University during Aug. 24 - 28. The school system. The coupling between the electromagnetic provided a wide spectrum of plasma-related field and various degrees of freedom of plasma is courses, including the fusion technology, space highly nonlinear, hence parametric instabilities are plasma physics, laser plasma science and ubiquitous. Whether the effects are useful or micorwave techniques et al. Our students can detrimental, it is essential to control these learn different plasma-related research topics, instabilities. The onset of instability can usually be which can stimulate them to study their own studied analytically by perturbation techniques, problems with a broader point of views. but the saturation or stabilization of these effects In order to complement the local plasma may not. Computer simulation can serve as physics courses, we invited Prof. Liu Chen numerical experiments to explore the control (University of California, Irvine, USA) to give methods with low cost and great flexibility in the lectures on nonlinear plasma physics during May parameter space. The nonlinear theory is an 1, May 4 and Sep. 1 - 4. The contents of the essential guideline and acts as the complementary lectures include most essential topics for the tool for the study of these problems. In the nonlinear analysis of the plasma physics, e.g. program, the focused research topics includes the nonlinear mode-mode coupling, parametric laser wakefield electron accelerators, laser-based interactions, and drift wave turbulence et al. The proton accelerators, radiaiton sources based on the nonlinear analysis can provide more precise laser-plasma interactions and electron cyclotron guideline for the computer simulation and resonance and plasma-based nonlinear optics et al. experimental designs, as compared to the linear theory. Laser/Maser Plasma interaction is a highly II. Activities nonlinear problem, the lectures provide the The major activity of the topical program is the students and researchers a starting point to apply laser plasma summer shcool. Due to the the nonlinear analysis on the study of Laser/Maser reorganiztion of the courses of the summer school plasma science. and some similar summer shools were held in Taiwan during the summer vacation, the annual We also held a particle-in-cell training course summer shool was cancelled this year. Even during Jul. 21 - 23. The purpose of the training thoguh, some of key members were helping course is to help students and researchers get organize 4th Asia Summer School and familiar with the simulation technique and start to Symposium on Laser-plasma Acceleration and apply the particle simulation on their research Radiation (http://www.hope.nthu.edu.tw/4th_ works after the course. ASS/), which was held at NSRRC of Taiwan In order to keep our students and researchers during Aug. 17 - 21, 2009. They also gave lectures updated with the newly development of the laser/ at the summer school. The students and maser plasma science, we held a journal club by researchers learned the fundamental knowledge of reporting the newest publications on the journals laser plasma physics and the newest development of high impact from Mar. 2009. The activities are of the field. So the Asia summer school is a still regularly held at National Central University.

183 ‹‹- Highlights of Programs III. Visitors and International discussed the possibility of future collaboration on Collaborations the laser fusion project. Prof. Liu Chen came to visit us during the The topical program supported the visit of Dr. beginning of May and Sep., 2009. He gave Mikhail Glyavin (Russian Academy of Sciences) lectures at National Central University during his at National Tsing Hua University during Jun. 9 - stay and had discussions with local researchers 13, 2009. Dr. Glyavin was hosted by Prof. T. H. about the apllication of the nonlinear analysis on Chang and his major research work is to develop the study of the laser/maser plasma interactions. the terahertz radiation sources based on the We decided to start the collaborations from the electron cyclotron maser (gyrotron). Recently, Dr. analysis of the gyrotron backward-wave Glyavin developed a pulsed magnetic field up to oscillators (gyro-BWO) and obtain the possible 40 Tesla, which was applied to generate high- physical reasons for its non-stationary behaviors. power coherent terahertz radiation (Phys. Rev. The experiences of the nonlinear analysis will be Lett. 100, 015101 (2008)). He gave a talk, which extended to other topics, e.g. the relativistic high title is "review of powerful pulsed terahertz harmonics generation from the interactions gyrotrons," at NCTS on Jun. 10. between the laser and solid targets et al. We are collaborating with Prof. Ang Lay Kee IV. Highlights of Research Results (Nanyang Technological University, Sigapore) and 1. A versatile three-beamline two-wavelength Dr. Koh Wee Shing (Institute of High) to study the 100-TW laser system with high stability and space charge effects in a LWFA. The research spatiotemporal quality has been constructed in works require the extension of the electrostatic National Central University. The laser will be model for evaluating the space charge limiting used for the development of advanced laser- current to the relativistic electromagnetic model. wakefield electron acceleration, proton Our computer simulation results can provide a acceleration, soft x-ray laser, high-harmonic guideline for the improvement of their old theory. generation, plasma nonlinear optics, etc. (Hsu- We invited Dr. Koh Wee Shing to visit NCU and Hsin Chu, invited talk at 2009 Cross-Strait our discussions made the works well-organized. Symposium on the Fusion Energy and Plasma Dr. Koh also introduced his team works on the Science, CSS- FEP) study of surface plasmonics, and we plan to apply 2. Relativistic optical rectification is analyzed by the particle simulation on the study of the utilizing the analytical solutions of the three- nonlinear behavior of the surface plasmonics. dimensional collective electron motion driven We also collaborate with Prof. Chuan Sheng by a high-intensity pulsed Gaussian beam. Liu (University of Maryland, USA) on the study Under the paraxial expansion the slowly of the LWFA and laser-based proton accelerators, varying components in the nonlinear and the recent works have been submitted to oscillation of electron density and electric Physics of Plasmas. The theoretical analysis for current are extracted from the solutions first, the beam energy scaling of the LWFA will be then they are used in the Maxwell equations as published soon. the source terms to calculate the terahertz electromagnetic fields as functions of the The joint works with scientists in the Institute spatiotemporal amplitude of the pulsed of Plasma Physics, Chinese Academy of Sciences, Gaussian beam. The analysis compares well Hefei, are to develop a fully relativistic Fokker- with available experimental data and computer Planck code for studying electron cyclotron wave simulations, and demonstrates the general heating in tokamak, an axisymmetric magnetic scheme of paraxial expansion for the analysis confinement device for magnetic fusion energy of relativistic nonlinear optical interactions. research. The code can also be used to study the (Jyhpyng Wang, presented at OCPA6, problems of electron transport in fast-ignition LanZhou, China, 2009) plasmas in laser fusion. Professor Z. M. Sheng of the Institute of Plasma Studies, Shanghai Jiao 3. We are studying the thermal relaxation Tong University visited us in August. We have phenomenon due to electron-ion collision in

Highlights of Programs -›› 184 fully ionized plasmas by using a 1-dimensional V. Publications PIC simulation code. The collision is modeled [1] Beam Energy Scaling of a Stably Operated by successive small-angle scatterings of Laser Wakefield Accelerator, Shih-Hung Chen electrons by a fixed positive ion background et al, submitted to Physics of Plasmas. using a Monte-Carlo procedure. The [2] Relativistic optical rectification driven by a breakdown of the ND2 law in the 1-D high-intensity pulsed Gaussian beam, Gin-yih simulation is also observed. The phenomenon Tsaur and Jyhpyng Wang, Phys. Rev. A 80, of numerical thermalization in the PIC 023802 (2009). simulation of a Lorentz plasma is investigated. The thermalization time of the simulation is reduced in the presence of the additional Monte-Carlo collision which simulates the electron-ion pitch angle scattering. (Yu-Ren Linliu, invited talk at 2009 Cross-Strait Symposium on the Fusion Energy and Plasma Science, CSS- FEP)

185 ‹‹- Highlights of Programs Highlights of Programs

Initiative (sub-project I): Establish GPU-based Supercomputing Platform

Coordinator: Ting-Wai Chiu (National Taiwan University; email: [email protected]) Committee members: Tzi-Hong Chiueh, Ying-Jer Kao (National Taiwan University)

I. Brief Description Center for Quantum Science and Engineering (CQSE)[http://cqse.ntu.edu.tw] on the innovative idea of establishing a GPU cluster as a supercomputing platform in large-scale scientific uring the last two years, the GPU computations. The 2009 budget of GPU initiative (Graphic Processing Unit) on a graphic only constitutes of the hardware money. It has card has emerged as a powerful device for high- been used in acquiring 4 units of Supermicro performance computing, even though it was servers, as the hosts of the 8 units of Nvidia Tesla primarily designed for the graphic display and S1070 (with 32 GPUs, and 32 x 4 Gbytes). Our computer games. With a price of NT$14,000, a objective in 2009 is to set up the hardware, and to graphic card (e.g., Nvidia GTX285) can deliver develop the CUDA codes for the large-scale greater than 100 Gflops (sustained) computing computations in lattice QCD, quantum spin power, which is 10-100 times faster than a single systems, and cosmology. CPU. The reason behind the overwhelming floating-point capability of GPU is that GPU is II. Activities designed for intensive and highly parallel In “The 2009 Taipei Workshop on Lattice QCD computations (i.e., graphics rendering ), in which (December 13-15)” http://twqcd09.phys.ntu.edu. more transistors are devoted to data processing tw/ , we have invited the renown GPU expert, Dr. rather than data caching and flow control. Thus a Mark Harris to give a series of lectures on CUDA GPU cannot stand alone in a computer system, but programming and optimization. Dr. Mark Harris’s only works as a powerful floating-point lectures will attract a lot of participants from coprocessor of the CPU. With a GPU card, one many other fields in science and engineering. can immediately turn any PC into a personal supercomputer. This opens up a great opportunity III. Highlights of Research Results for many scientific and engineering problems (A) The GPU supercomputer at CQSE which require enormous amount of number- crunching power. Recall that in the past 50 years, We have successfully set up the GPU cluster at every 10 times jump in computing power CQSE (see Fig. 1), constituting of 16 units of motivated new ways of computing, which in turn Nvidia Tesla S1070 (with total 16 x 4 GPUs, 16 x led to many scientific breakthroughs. 64 Gbytes, and peak 64 Teraflops) connecting to 16 servers (with total 16 x 2 Intel Quadcore CPUs, The goal of the NCTSn GPU initiative is to and total 16 x 32 Gbytes). This is the first GPU collaborate with the Subproject 5 of the NTU supercomputer successfully installed in Taiwan. It

Highlights of Focus Group -›› 186 We proposed an alternative large-scale structure formation model, where the dark matter particles are very light such that they are condensed in the Bose-Einstein state. It essentially solves the time-dependent Schrodinger equation with a self-consistent, time-dependent gravitational potential. This work incorporates some critical solvers developed in (1), such as the Poisson solver and the AMR scheme. We have finished the coding and testing of this code in Nov. 2009, and are ready to execute a few production-run simulations in the near future.

(D) Tensor Network Method for Quantum Spin System We have developed efficient tensor contraction codes for tensor network method to study frustrated spin systems in two and three dimensions. We have achieved at least 20x speedup for the tensor contraction kernel, and we are in the process of finalizing the full version Fig. 1 The GPU supercomputer at the Center of Quantum code. Science and Engineering (E) Large-scale simulation of unquenched lattice has been in production runs since February 2009. QCD We have developed highly efficient CUDA We have developed a highly efficient CUDA (Compute Unified Device Architecture ) codes for code for Monte Carlo simulation of lattice QCD the computationally challenging problems in with exact chiral symmetry, attaining sustained quantum chromodynamics (QCD), quantum spin 140 Gflops for a single GPU. Also, we are the first systems, and astrophysics. With our GPU group around the world performing a large scale supercomputer, we have attained 8 Tflops simulation of lattice QCD with a GPU cluster. So (sustained) at a price NT$5,000,000. Thus we can far, there are only 3 lattice groups tackle many large scale computations, without (RBC+UKQCD, JLQCD, and TWQCD) around using the prohibitively expensive supercomputers. the world who are capable to simulate lattice QCD Note that the price/performance ratio of our GPU with exact chiral symmetry. supercomputer is less than 1/100 of a conventional supercomputer (e.g. IBM BlueGene/L), and only IV. Outlook 1/10 of the power consumption of the IBM BlueGene/L. One of the main objectives of 2010 is to develop highly efficient CUDA codes for (B) AMR for Fluid and Gravity MultiGPUs under MPI and OpenMP, for lattice We have developed a generic parallel GPU QCD, quantum spin systems, and cosmology. We acceleration Adaptive-Mesh-Refinement (AMR) plan to hire a postdoc under the Subproject 5 of code for fluid and gravity, with the application to CQSE, and 2-3 graduate research assistants, cosmology large-scale structure formation. It is focusing on innovative numerical algorithms and the first of its kind in computational physics, and CUDA optimization. We outline our 2010 work it has been accepted for publication in plan as follows. Astrophysical Journal Supplement (Impact (1) We will organize intensive training courses factor=13). aiming for graduate students and postdocs. (C) Large-Scale Structure Formation Model Our purpose is to speed up the learning processes of programming GPU, and build a

187 ‹‹- Highlights of Focus Group team of researchers who will become the core impossible in the CPU version of our code of the future GPU research. due to the massive CPU time needed. In addition, we will develop GPU version of (2) For the Adaptive-Mesh-Refinement (AMR) classical Monte Carlo codes, which has been code for fluid and gravity, we will incorporate proven successful in Ising models. Our goal is the dark matter particles in this hydro+gravity to further push the methods to systems with code as well as to improve the fluid solver impurities and frustration. with a higher-order Riemann scheme. (6) For the Monte Carlo simulation of lattice (3) We will continue the production run of time- QCD with exact chiral symmetry, we will dependent Schrodinger equation with a self- continue the production runs for the consistent and time-dependent gravitational (2+1)-flavor QCD with optimal domain-wall potential, where the mesh refinement will quarks. Also, we will develop the CUDA code achieve up to 10 levels (with 2**10 finer for the study of a Technicolor theory with Nf meshes) at the highly collapsed regions so as techniquarks, to find out whether there is a to resolve the core property of dark matter conformal window at large Nf, which is one halos. In addition, a stellar disk will be of the most interesting topics in the strong included in the dark matter halo to examine interaction physics, relating to the Large how well a stellar disk may survive in the Hadron Collider (LHC). presence of the halo density granulations arising from the uncertainty principle. V. Publications (4) We will port the computational intensive [1] “GAMER: a GPU-Accelerated Adaptive codes from CPU to GPU. For example, to Mesh Refinement Code for Astrophysics”, identify the unbound particles in a N-particle Hsi-Yu Schive, Yu-Chih Tsai, Tzihong system, where of order N**3 computations Chiueh, to be published in Astrophysical are required, with N ranging from 10**5 to Journal Supplement (2009). 10**6. [2] “TWQCD’s dynamical DWF project”, T.W. (5) We will use our efficient tensor contraction Chiu, T.S. Guu, T.H. Hsieh, C.H. Huang, Y.Y. CUDA codes to study the frustrated J1-J2 Lee, Y.Y. Mao, K. Ogawa, P.K. Tseng, to be Heisenberg model by increasing the virtual published in PoS (LAT2009)034. dimension and lattice sizes of systems. This is

Highlights of Focus Group -›› 188 Initiative (sub-project I): Build-up of Theory Support for LHC Physics

Coordinator: George Wei-Shu Hou (National Taiwan University; [email protected])

I. Brief Description part of the NTU 拔尖 Project “Scaling the Particle Frontier”, which can be viewed as the matching fund from NTU for this Initiative through MOE. No new routine seminar activity is directly oal: As titled. introduced, as one enjoys the forum of contact Coordinator: George W.S. Hou already established in the past, the Particle Key Members: Xia o-G a n g H e, F r a n c e s c a Physics Journal Club held at Monday lunch time at NTU, and sponsored by LHC FG. This JC is an Borzumati (NTU拔尖), Johan Alwall (NCTSn); unusual setting in Taiwan, where both theorists also Hsiang-nan Li and Tzu-Chiang Yuan of AS and experimentalists are present in good numbers, Plus: close contact with experimental colleagues ranging from mature researchers to beginning (mostly CMS) Kai-Feng Chen, Paoti Chang, students. It was established during the Belle era, Minzu Wang, Bob Hsiung (NTU) Yuan Chao, which is exemplary for the good TH-EXP cross- Rong-Shyang Lu, Paolo Bartalini (NTU拔尖) fertilization. In anticipation of the LHC era , the Yuan-Hann Chang, Shin-Shan Yu, Chia-Ming Kuo JC was broadened to Particle Physics a few years (NCU) Song-Ming Wang of AS in ATLAS ago. The NTUHEP group receives significant Group Size: above, plus postdocs, visitors and funding from NSC and NTU, and has significant students, altogether over a dozen theorists manpower base. The purpose of this TH-LHC (matching with NTU拔尖Project "Scaling the Initiative is to try to replicate the success of the Particle Frontier", where the Coordinator is the Belle era, into the LHC era, to put Taiwan on the CI) map of LHC physics. Research Focus (from Phase-III 6-year proposal A special goal for 2009, as written in the of NCTS): 6-year proposal filed in late 2008 (see http://phys. Before 2012 cts.ntu.edu.tw/data/proposal.pdf), is to hold the Second Workshop on Beyond 3 Generation Help find t' and b' quarks at LHC, and Standard Model elucidate associated Flavor and CP Violation physics (other topics of course pursued). http://indico.cern.ch/conferenceDisplay. py?confId=68036 Before 2015 which is now scheduled to be held January Help elucidate the impact on CPV for BAU, 14-16 2010 on NTU campus (original date was EWSB and New Resonances, and prepare for December, but in deference to a workshop at Super B factory and ILC. CERN, it was shifted to January; this is still within the approved 2009 budget extension to II. Activities 3/2010). This is a follow-up on the first workshop, Unlike the FGs of past 5 years, the Initiative is http://indico.cern.ch/conferenceDisplay. a new concept or approach at NCTS North/ py?confId=33285, held at CERN in Sept. 2008. Physics. The purpose of this “TH-LHC Initiative” The current workshop is now subtitled “New is to bring in strong enough theory manpower, to Fermions at the Crossroads of Tevatron and enhance contact with cutting edge experiment for LHC”, because of the slow start of LHC. The mutual benefit. It also complements the Theory small scale workshop will bring in over two dozen

189 ‹‹- Highlights of Focus Group international researchers with active interests in We are delighted especially with the studying and understanding the 4th generation, to exceptional catch of Dr. Johan Alwall, a establish an “international consortium” (wording MadGraph/MadEvent author and expert, and a from 6-year proposal), with Taiwan as a main hub very good and broad particle phenomenologist, to for activity. It should be emphasized that join the TH-LHC Initiative for a 5-year term (3+2 practically all international participants will be years, as per 6-year proposal) starting 1/2010. Dr. attending the workshop using their own funds. Alwall first arrived during summer 2009 as a This is one thing we wish to introduce into Taiwan visitor from SLAC. We managed to attract him to in general, and NCTS funded meetings in stay for the 5-year assistant fellow job, rather than particular — people attend our workshop because the 3-year postdoc position that he would have it is of interest, not because their expenses are continued on to at Fermilab. This in a way already paid for ! puts NCTS North’s TH-LHC Initiative on the map. We have received very strong We also wish to emphasize that, the reason for th recommendations, in particular to help/allow Dr. targeting the 4 generation study for experiment, Alwall nurture a small start-up research group, and with heightened theory support from NCTS which is precisely the design goal of our original North, is laid out clearly in the 6-year proposal, 6-year proposal, and the timing cannot be better which received favorable review in 12/2008. for the scheduled restart of LHC for high energy With new manpower brought in during 2009 collisions in early 2010. The 5 year period of under the Initiative, we have studied CP violating 2010-2014 could be the start of a Golden Age, for asymmetries in b' → s decays, 4th generation us to take part in. As stated by one recommender decaying to dark matter, a comprehensive study of (Kaoru Hagiwara of KEK), he himself would visit b' and t' decay modes and rates, and initiated how Dr. Alwall to collaborate, and through Dr. Alwall, to distinguish 4th generation from SUSY if a a web of international collaborations and signal is found. Note that the latter two are joint exchanges with SLAC, Fermilab, IPMU, UC efforts between theory and experiment. New Irvine, UC Louvain, etc., would be established projects have also been initiated to understand and cultivated, which would be on top of our neutron EDM, study of possibility of large existing contacts. Yukawa driven EWSB on a lattice (how to define th As planned in the 6-year proposal, two 5-year the problem), elucidate CPV strength with 4 term positions have been advertised for the generation, etc. Some of these may already come TH-LHC Initiative, which appeared in the June to fruition in 2010. 2009 issue of Physics Today. This has been Students, postdocs and junior colleagues have reemphasized recently on HEPIC/SPIRES, and been sent to attend schools like Les Houches, or transmitted personally to a few leading Japanese conferences like EPS-HEP, and visiting places like colleagues, to attract Japanese applicants (which is UC Irvine, Caltech, or IPMU Tokyo, and KEK. happening). We wish to get the best applicant we can! Since the NCTS North budget, as pre- III. Visitors and International allocated by the 6-year Phase-III ad hoc review Collaborations panel of NSC at end of 2008, can support only one The two main intermediate-term visitors during 5-year term under the TH-LHC Initiative, 2009 are: Prof. Abdesslam Arhrib (April– matching from NTU university side would be October), a long time collaborator with many sought for the second position. This is one major theorists in Taiwan, including the Coordinator, responsibility of the NCTS North director, which Prof. Hou; and Dr. Johan Alwall (August, and is also the Coordinator of this Initiative. October–December; see below). Short term Please do appreciate that the aim of NCTS visitors are variably sponsored between TH-LHC North TH-LHC Initiative is to be internationally Initiative, LHC FG, and CTS of NTU (college visible, rather than just “national”. This is the true funded), where examples are Chung Kao, Hsin- nature of particle physics itself, and Taiwan ought Chia Cheng, Ian Low, and Masaya Kohda and to be not self-limiting. Teruki Kamon.

Highlights of Focus Group -›› 190 IV. Highlights of Research Results proposal as the reason for focus, beyond just The highlight result of 2009 is the insight work supporting the set experimental agenda of the joint of the Coordinator, Prof. Hou, on the 1015 NTU-NCU analysis effort at CMS, is now well enhancement of possible CP violation strength, tested in front of world-wide erudite audiences. To as one extends from 3 generation Kobayashi- quote from the 6-year proposal: Maskawa model (2008 Nobel Prize) to a 4th I f 4 th generation is ruled out (will take ~ 5 generation: The KM structure can provide years) by our combined Exp/TH efforts, the sufficient CPV for generating the (visible) accumulated manpower would have a foothold Universe. In accord with the experimental strategy on the developments of LHC physics, i.e. of 漢中策略 (laid down in early 2006; see 6-year whatever may emerge on Mass Generation, proposal), people still frown on the 4th generation, and pursue what we have learned. But clearly, hence the paper is published in Chinese Journal of in preparing in advance for uncovering the 4th Physics (47, 134 (2009)). But it is our judgment generation, if we help find it and elucidate its that this observation alone makes the 4th generation properties and impact, NCTS-North/Physics extremely attractive. Prof. Hou has focused his would no doubt become a world-renowned work in the past 4 years on insights of B physics Center. No other way can approach this level and CP Violation in regards the 4th generation, and of recognition. the work is now quite visible. The prediction for → But of course, the manpower build-up is not large and negative CP phase in Bs J/ψ φ is th currently being vigorously pursued by the CDF limited to 4 generation physics. Not only we would carry out a broad agenda interfacing with and Dzero experiments at Fermilab, and will soon 拔 be superseded by the LHCb experiment at LHC. LHC FG (as well as the theory arm of the NTU 尖計畫), the purpose is to bring the NCTS North The Coordinator, Prof. Hou, has taken 2009 setting into the LHC era, which would last at least “campaigning” worldwide for the 4th generation for the next 20 years. cause, giving seminars and colloquia, many of which invited, at IPMU, Washington (Seattle), V. Selected Publications SLAC, Virginia, William and Mary, Fermilab, [1] The aforementioned Chin. J. Phys. 47, 134 Chicago, Ecole Polytechique, CERN, Osaka, (2009) would likely become eminent (and in a Bonn, UC Irvine, UCLA, and Caltech; and Taiwan journal). Another worthy work is domestically at AS, NTU, NTHU, NCU and Phys. Rev. D 80, 076005 (2009). Several NCKU. Presentations have also been given in manuscripts would appear by December conferences and workshops at CERN, and at review time. ICHEP08 and FPCP09, with associates giving presentations at EPS-HEP09, as well as [2] The Coordinator, Prof. Hou, also published a domestically. In general, the broad impact picture book volume in the Springer Tracts in Modern Physics in 2009, titled Flavor Physics and the is very well received, with people appreciatively th calling the talk “excellent”. Of course, it remains TeV Scale, where the case for a 4 generation that there are still few believers, despite the from flavor physics and CP violation is also outlined and emphasized from B physics and success of the talks, because of a deeply-ingrained → prejudice (which is cashed in as basis for the especially b s CP violation data. But this experimental 漢中策略) against the 4th generation. monograph was written largely in 2008, and So, the basic broad idea, outlined in 6-year NCTS was not directly acknowledged.

191 ‹‹- Highlights of Focus Group Initiative (sub-project I): Theory and Simulation of Plasmonic Metamaterials

Coordinator: Guang-Yu Guo (National Chengchi University/National Taiwan University; email: [email protected]) Committee members: Michitoshi Hayashi, Ming-Wen Chu (National Taiwan Univ.)

I. Brief Description individual Ag and Au nanoparticles (NPs). The plasmonics critically relies on the detailed knowledge of electric near fields associated with various surface-plasmon modes on metallic NPs. urface plasmon polaritons (SPPs) are The STEM-EELS routinely provides the electromagnetic waves confined to a nanometer spatial resolution by focusing a metal-dielectric interface and coupled to the subnanometer electron beam (~2 Å) on NPs and quantized collective oscillation of free charge analyzing the energy losses of the electrons to the carriers. The low-dimension nature of SPPs and NPs. A nanometer-scale resolution is difficult to the strong electromagnetic field at the interface attain by conventional optical approaches such as are responsible for a number of fascinating scanning near-field optical microscopy that phenomena in fundamental science and exciting marginally attains a spatial resolution of ~20 nm. opportunities for technological applications such While experiments plunge ahead, they need as enhancing Raman scattering by astronomical strong theory support. Having identified this orders, enabling extraordinary transmission of direction as promising, and with Taipei taking the light through nanoholes, guiding electromagnetic lead, we wish to enhance Theory Support, to waves with SPPs beyond the diffraction limit. hopefully make a difference over 5-6 years. Therefore, plasmonic nanostructures have been attracting an enormous amount of experimental Therefore, the main purpose this year is to and theoretical interest worldwide in recent years. build up internationally competative Theory Support for Plasmonic Metamaterials. To this end, Indeed, a large number of experimental groups we have proceeded in two directions: (1) to hunt in Taiwan, in particular, the prominent groups of for quality overseas scientists to work in the Cheng-Hsuan Chen (NTU-CCMS), Yang-Fang NCTSn as either long term fellows/postdocs or Chen and Ding-Ping Tsai (NTU-Physics) in NTU, short term visiting scientists, and (2) to build up have already begun to conduct research in in-house expertise of theory and simulation of plasmonics-related nano-sciences and plasmonic metamaterials. nanotechnologies in recent years. Indeed, Yang- Fang Chen’s group at NTU were able to II. Activities manipulate surface plasmon resonance electrically Build-up of the in-house theoretical team: for the first time in Au nanorod-liquid crystal devices. Through the composite of semiconductor To provide a platform for in-house professors, nanorods and metal nanoparticles, they postdocs and students to have discussions, to demonstrated that a suitable band alignment exchange ideas and to learn related theoretical between metal and semiconductor, the band gap methods and experimental techniques, we have emission of semiconductor nanorods can be organized a series of monthly informal meetings greatly enhanced, while defect emission can be since last May (2009). For example, in the first suppressed to noise level. Cheng-Hsuan Chen’s meeting, G.-Y. Guo gave a review on open source group has established the combined technique of computer codes for plasmonic metamaterials scanning transmission electron microscopy simulations, explaining the advantages and (STEM) in conjunction with electron energy-loss disadvantages of several commonly used methods spectroscopy (EELS) and its applications for including plane wave expansion (photonic band mapping and probing plasmonics modes in structure) (MIT MPB), finite difference time-

Highlights of Focus Group -›› 192 domain (FDTD) (MEEP), Mie theory and Moroz. M.-W. Chu and G.-Y. Guo have been multiple-scattering theory (KKR) (Wave- jointly training a student to develop a theory for scattering.com), and discrete dipole approximation describing interaction of relativistic electron beam (DDSCAT). In the same meeting, M.-W. Chu also with plasmons on metal surfaces. Ding-Ping Tsai gave a talk on their latest STEM-EELS results also has one postdoc and one PhD student which would need theoretical calculations to learning how to simulate nanoplasmonics using understand. the FDTD method. Encouragingly, after intensive work in the past several months, our team In the meeting last June, M. Hayashi gave a members have mastered a few basic theories and review on current status of understanding of the computational methods, and are ready to work detailed mechanism of surface enhanced Raman with our experimental colleagues as well as our scattering (SERS), one of the key issues in the distinguished foreign visitors to tackle some field of nanoplamonics. He also outlined how one fascinating issues in the field of plasmonics and can resolve some of the fundamental issues metamaterials. concerning SERS by performing ab initio quantum mechanical [e.g., time-dependent density functional theory (TD-DFT)] calculations. G.-Y. III. Visitors and International Guo, on the other hand, spent some time Collaborations explaining in detail how the DDA and the Through connections with international friends associated DDSCAT code work. He illustrated this and colleagues, we have been able to invite well by presenting his own calculations for a few Ag known scientists in the field, V. Klimov (PN and Au nanoparticle clusters. Lebedev Physics Institute) (Sept. 15-Nov. 23, 2009) and A. Alexander Moroz (wavescattering. As mentioned above, plasmonics and com) (Oct. 2-23, 2009). Their visits have been metamaterials are currently a very hot field and very helpful and fruitful. Both of them gave at therefore there are many experimental and least two seminars/lectures each in both NTU and theoretical groups in other Taiwan institutions NTNU. Furthermore, they have had intensive actively working on it. Therefore, in Oct. 2-3, discussions and exchanged ideas with both 2009, we organized a workshop titled Plasmonics experimentalists and theoreticians alike from both in Metal Nanoparticles: Experiment and Theory, NTU and other institutions. For example, A. to provide an opportunity for domestic scientists Moroz is a world expert using the KKR methods to present latest results, to exchange ideas and to study electromagnetic responses of nanoparticle experience, and lastly but not the least, to educate clusters and photonic crystals. During his stay, he our young researchers (students, postdocs and met with the students in NTU-Physics many even faculty members). The workshop was very times, teaching them how to use the KKR method. successful and was attended by more than 60 participants from all over Taiwan. In the last week of this month, Che-Ting Chan of Hong Kong Univ. of Science and Technology, Since last April (2009), we have been actively will visit NCTSn. During his stay, C.-T. Chan will training our young researchers with widely used give two lectures titled Using transformation theoretical methods and also ourselves with new optics to create illusion and the physical theoretical techniques. For example, M. Hayashi properties of plasmonic lattices in the forthcoming has been teaching one student, one research Mini-school on Plasmonic Metamaterials in NTU. assistant and one postdoc how to perform excited Furthermore, Mark Stockman of Georgia State state calculations for metallic nanoparticle- Univ. will visit NCTSn and NTU-Physics in mid- molecular systems in order to understand fully the December for about nine days. microscopic mechanism of SERS. G.-Y. Guo has been teaching two students how to use the DDA IV. Highlights of Research Results and KKR methods to calculate electromagnetic responses of metallic nanoparticle clusters. The 1. Fundamental properties of clusters of strongly students who are learning the KKR method, also interacting plasmonic nanoparticles benefited greatly from the three-week visit of A. Main characteristic features of plasmonic

193 ‹‹- Highlights of Focus Group resonances depend critically on shape. These techniques for single molecule detection. The features allow tuning interaction between requirement for single molecule detection using nanoparticles and light and molecules. A best way Raman spectroscopy is that the cross section is to control plasmon resonances is clusters of enhanced by a factor of 1014-1015. These huge simple nanoparticles. It was shown already that enhancements have been achieved using silver cluster of two nanospheres has unique optical nanoparticles in conjunction with resonance properties which cannot in principle be achieved enhancements due to a molecular electronic in single nanoparticles. Cluster of three and more transition. Although SERS was discovered several nanoparticles are also of great interest. During the decades ago, a complete picture of the present visit of V. Klimov in NCTSn, we have enhancement mechanism is not available, due to together investigated optical properties of three its highly complicated experimental conditions. cylinder clusters by using both approximate Electronic structure methods are ideal tools. Even analytical theory and numerical DDA calculations. so, due to the complicated metal cluster geometry, Fascinatingly, we found that in contrary to it is not clear how plasmon-like excitation forms common point of view the decreasing of system and what is the origin of such excitations. size results in transformation of dark modes into Our focus here is placed on constructing model very bright one. This interesting finding is systems that can provide a clear physical view of presented in a manuscript which is almost ready how plasmon-like excitations of a metal cluster for submission. The cluster samples of three Ag affect optical properties of the adsorbed molecule. cylinders are being made and will be investigated We take pyrazine as an adsorbate molecule and using the STEM-EELS by C. H. Chen and M.-W. Nan or Agn as metal cluster systems. We have Chu’s experimental team in the CCMS-NTU in constructed a clear physical model of the the coming months. interaction between plasmon-like excitations and 2. Plasmonic metamaterials with negative the adsorbed molecule and also established a full refraction and related effects quantum mechanical approach to this issue. We have explored recent TD-DFT methods and time- The development of plasmonic metamaterials dependent coupled-perturbated Kohn-Sham started from the idea of negative refraction and equation technique to calculate electronic perfect lens in 2000 by J. Pendry. Despite fast excitation properties and dynamic polarizabilities. development of this area the initial idea of perfect We are now able to investigate the most recent lens is still very controversial and paradoxical. It issue on how plasmon affects optical properties of was shown recently that a perfect lens cannot be adsorbed molecular systems including emission realized in principle. Moreover during the present and non-radiative electronic transitions. A full visit of V. Klimov in NCTSn, we have together quantum mechanical study on this issue is crucial demonstrated that another important idea of to the experimentalists who have been trying to negative refraction media (antimatter theorem) by modify the optical properties of the adsorbed J. Pendry and his coworkers also has very limited molecules by controlling plasmon of metallic region of applicability (far fields only). Our nano-structures. results show the crucial role of surface plasmons in left-handed materials (LHM) and pave the way 4. STEM-EELS probe of metal nanoparticles to develop new applications on the base of full A major expenditure in the experimental front control of surface plasmons in LHM (preparation in the past year has been the establishment of the of entangled states for quantum computing and to combined technique of STEM and EELS, and its effective excitation of nanosized light sources for applications for mapping and probing plasmonics plasmonic computer of next generation). A modes in individual Ag and Au nanoparticles manuscript on these results is being prepared. (NPs). An electron beam can excite SPs by 3. Quantum mechanics treatment of interaction coupling to their evanescent-field components of plasmons with molecular systems close to the NP surface and yields detailed information on the spatial distribution of the SPs. Surface-enhanced Raman scattering has This STEM-EELS technique, therefore, gives rise opened the possibilities of using Raman

Highlights of Focus Group -›› 194 to a very powerful tool for studying SP properties [2] H. Y. Xie, P. T. Leung, D. P. Tsai, “General of NPs, which often exhibit a range of distribution validity of reciprocity in quantum mechanics,” in sizes and shapes. STEM-EELS overcomes the Phys. Rev. A 78, 64101 (2008). averaging problems encountered in macroscopic [3] K. M. Lin and G. Y. Guo, “Uncoupled modes optical measurements and gives us the unique and all-angle negative refraction in walled capability of performing local spectroscopy on honeycomb photonic crystals”, individual nano-object with (sub-)nanometer J. Opt. Soc. Am. B 25, C75 (2008). spatial resolution. We have demonstrated the 2009: applications of STEM-EELS in unveiling (a) various SP modes in individual and coupled Ag [1] H. Y. Xie, P. T. Leung and D. P. Tsai, “General and Au NPs in the near-infrared to UV regimes proof of optical reciprocity for nonlocal and (b) UV-range surface resonances in electrodynamics,” J. Phys. A: Math. Theor. semiconductors. 42, 045402 (2009). Plasmonics has been a field of extensive [2] H. Y. Xie, P. T. Leung, D. P. Tsai, “Molecular research focuses since over two decades, whereas decay rates and emission frequencies in the STEM-EELS for SPs investigations was not vicinity of an anisotropic metamaterial,” Solid realized until 2007. Our STEM-EELS facility is, State Commun. 149, 625 (2009). to date, the first and only STEM in Taiwan and [3] K. P. Chiu, K. F. Lai, S. C. Yen, D. P. Tsai, one of the very few STEMs in the world (4) “Surface plasmon polariton coupling between capable of carrying out high resolution EELS. The nano recording marks and their effect on electron monochromator is characterized by a optical read-out signal,” Opt. Rev. 16, 326 superb energy resolution (~0.14 eV), and a weak (2009). elastic tail that enables one to tackle electronic [4] H. Y. Xie, P. T. Leung, D. P. Tsai, excitations down to the near-infrared spectral “Clarification and extension of the optical regime (~1 eV). Up to date, only four STEM- reciprocity theorem,” J. Math. Phys. 50, EELS groups in the world can perform plasmonics 072901 (2009). researches. [5] K. P. Chiu, N. L. Wu, C. S. Wu, Y. H. Fu, C. H. Chu, H. Y. Chung, F. H. Chen, L. D. Lin, V. Publications L. H. Huang, C. D. Shue, and D. P. Tsai, 2008: “Plasmonic nanostructures for photo-catalytic [1] K. P. Chiu, K. F. Kai, D. P. Tsai, “Application reactors,” Proceedings of SPIE 7392, 73920B of surface polariton coupling between nano (2009). recording marks to optical data storage,” Optics Express 16, 13885 (2008.)

195 ‹‹- Highlights of Focus Group Research Activities of Individuals

Research Activities on High Energy Physics

Abdesslam Arhrib (University of AbdelMalek Essaadi; email: [email protected]) Visiting associate professor, 2009/4/17~2009/10/26

uring my stay at National Center for measure different CPV phase combinations, and theoretical Sciences in National Taiwan form the traditional agenda of New Physics CPV University, I have been working on diderent search in flavor sector. The study of b' → s decays projects in collaboration with scientists from would open up the genuine, new chapter of very National Taiwan University (NTU), National heavy flavor sector for CPV studies. Furthermore, Tsing Hua University (NTHU) and National although it is of DCPV type, unlike DCPV in B → Cheng Kung University (NCKU). decays but like TCPV in Bs J/ψφ (there is no longer the exquisite TCPV mechanism for b'), the My research has concentrated on strong phases in b' → s transitions are calculable. phenomenological studies relevant to Large Hadron Colliders (LHC). I have been We have shown that, asymmetries could reach → → investigating phenomenology of various 30% for b' sZ and b' sH for mb' ≈ 350 GeV extentions of Standard Model such as: Models and light Higgs, while it could reach above 50% → → with sequential fouth generation of quarks and for b' sγ and b' sg, and extend to higher mb' leptons, Supersymmetric Models as well as . The branching ratios are of order 10−3–10−5, and Models with an extended Higgs sectors such as CPV measurement would require tagging. Once two Higgs Doublet Models (2HDM) and triplet measured, however, the CPV phase canbe Higgs models. extracted withlittletheoretical uncertainty[1,2]. In collaboration withW.-S. Hou, we investigate In collaboration with R. Benbrik (NCKU), Direct CP Violation in Standard Model with Kingman Cheung (NTHU) and T.-C. Yuan sequential Fourth Generation quarks. With the (Academia scenica) we have studied the Higgs eminent start of LHC, we believe that it is time to boson efects on third-generation squark-pair survey the situation for CPV studies in 4th production in proton-proton collision at the CERN generation quark decays, in particular through b' Large Hadron Collider. We anticipate the → s transitions both in FCNC decay such as b' → contributions from the Higgs exchanges will be sX, X = γ, Z, H and gluon as well as in tree level 1 substantial at large tan β region, where the → 3 decay such as b' → sW+W −, with an smallness of the bottom-parton luminosity can be intermediate by up type quark q = u, c, t, t'. The compensated by enhancement of the bottom CPV studies in b' → s t r a n s i t i o n s i s Yukawa coupling. We found that substantial complementarity with low energy studies such as enhancement can be obtained through s-channel → → 0 0 Bs J/ψφ, or KL π ṽν, or in D mixing. The exchanges of Higgs bosons at large tan β, at which merit of CPV studies in b' → s transitions is its the enhancement mainly comes from bb,̄ bc̄, and c complementarity with low(er) energy studies such b̄ initial states. We compute the complete set of → → 0 as B s J/ψφ, or K L π ṽν mixing. These electroweak (EW) contributions to all production

Research Activities of Individuals -›› 196 channels. We found that the EW contributions can Invited Seminars be significant and can reach up to 25% in more • “Probing tripleHiggs couplings at colliders” general scenarios and at the resonance of the seminargiven at National Central University, heavy Higgs boson [3]. The size of Higgs th 17 june 2009. enhancement is comparable or even higher than • “Direct CP Violation in fourth generation the PDF uncertainties and than must be included in any reliable analysis. quark decays” seminar given at National Taiwan Universit, 12th October 2009 In collaboration with R. Benbrik, C.-H. • “Probing triple Higgs couplings at colliders” Chen(NCKU) and R.Guedes and R. Santos seminar given at National Tsing Hua (Southampton Univerity) we have investigated University, May 2009. double Higgs production at the LHC in the framework of the general two Higgs Doublet Model (2HDM). We include consider all CP-even double Higgs production, that is, References pp → h0h0, h0H, H0H0. We present the regions of [1] A.Arhrib andW.-S.Hou, “CP violationinFourth the parameter space of a general CP-conserving GenerationQuarkDecays”, Phys. Rev. 2HDM where this process is large enough to be D80:076005, 2009 probed at the LHC taking into account in our [2]  A. Arhrib and W.-S. Hou, “Direct CP calculation the various experimental constraints Violation in Fourth Generation b'→s on the 2HDM parameters as well as the tree-level Transitions at High Energy Collider” unitarity and vacuum stability constraints on the November 2009, in press various parameters of the Higgs potential. We [3] A.Arhrib, R.Benbrik, K.Cheung and T.-C. have shown that in some cases, even after Yuan, “Higgs boson enhancement effects on imposing all constraints, cross sections are still squark-pair production at the LHC”, large enough to allow for a determination of November 2009, in press 2HDM triple Higgs couplings. In other cases only [4] A. Arhrib, R. Benbrik, R. Guedes and R. a deviation from the SM can be measured and Santos, “Double Neutral Higgs production in other processes would be needed to complete the the Two-Higgs doublet model at the LHC”, picture. We have given particular attention to the JHEP 0908:035, 2009 decoupling limit where the lightest Higgs mimics the SM Higgs and look for the possible non- decoupling effects [4]. Conferences presentations • “Direct CP Violation in fourth generation quark decays” talk given at second LHC meeting, 24th October 2009 • “Double Higgs production in the CP conserving Two Higgs Doublet Model” talk given at PPP08, NCKU Tainan 22th May 2009

197 ‹‹- Research Activities of Individuals Research Activities on Algorithm Developing for Microarray Data Analyses

Chih-Hao Chen (Institute of Systems Biology and Bioinformatic, National Central University; email: [email protected]) Postdoctoral researcher, 2007/11/01~2009/08/31

uring the period I worked for NCTS, I high-resolution (more than 500K probes) arrays; focused on developing algorithms for this parameter has a thoroughly tested and high-resolution microarray analysis. My research strongly recommended default value. was initially aimed at improving existing In fact, the two user tunable parameters are all algorithms, in respect of computation speed, the parameters there is in SAD. There are no memory use and accuracy, for copy number other hidden parameters in the formulation. In variation (CNV) analysis for high-resolution other words, SAD does not contain within it a microarrays. I achieved my goal with a novel difficult-to-access “black box” (there are of course algorithm: Segmentation Analysis of DNA (SAD). lines of coding). In comparison, GLAD employs The manuscript for SAD is almost ready and, as more than a dozen parameters, some of whose the first attempt, will soon be submitted to Nature meaning are obscure. Methods for publication. A software package for the public is now downloadable at http://www. Because SAD employs exact mathematical sybbi.ncu.edu.tw/public_software.htm. relations and takes advantage of the scale- independence of the variance of array errors, it is SAD’s unique and outstanding features make it extremely fast. For a 1M-probe microarray it is by far the best -- faster, more user friendly, more two orders of magnitude faster than its closest compact, easier to understand, higher accuracy -- competitor, CBS [2], and more than three orders package for CNV analysis. These advantages of magnitude faster than GLAD [3] and CGHseg derive from a simple fact: the formulation of the [4]. Its speed advantage increases with array size SAD algorithm is based on simple and rigorous because unique among algorithms for similar task applications of statistical principles, measurement SAD scales linearly with array size. theory, and precise mathematical relations, and nothing else. Our extensive testing shows that SAD is no less accurate than its competitors. It gets better, SAD makes two (related) assumptions about comparatively, when signal to noise ratio on the data property: the normal distribution of and array worsens -- caused by stromal contamination, scale-independence of the variance of array errors. for instance. These are fully supported by microarray data. No further assumptions, implicit or explicit, are made Because the statistical nature of SAD in the formulation. An example of making an formulation and because all decisions are implicit assumption concerning data property determined by the one essential parameter, which occurs when data smoothing is practiced. An is a t-value, all SAD results are assigned example of the explicit kind is the assumption of quantitative statistics. This is another feature of the existence of hidden variable as in the case of SAD that is unique among algorithms for similar Hidden Markov Model [1]. tasks. As a result of the simplicity of the formulation In summary, SAD is formulated on solid SAD is extremely user-friendly. It has only two statistical principles and mathematical relations, it user-defined parameters. One is essentially a is simple and accessible, and it delivers the goods t-value which determines the resolution of the in terms of being user friendly, fast, accurate, and analysis. The other is a segment length which produces results with solid statistics. With all largely determines how fast the program runs for these attributes we believe SAD is a breakthrough in both theory and practice, and it has the potential

Research Activities of Individuals -›› 198 of making an important contribution to the field of [4] Picard, F., Robin, S., Lavielle, M., Vaisse, C. microarray analysis, and therefore to our & Daudin J. (2005) A statistical approach for understanding of human diseases.. array CGH data analysis. BMC Bioinforma., 6, 27.

References [1] Fridlyand,J. et al. (2004) Hidden Markov models approach to the analysis of array CGH data. J. Multivariate Anal., 90, 132–153 [2] Venkatraman, E.S. and Olshen, A.B. (2007) A faster circular binary segmentation algorithm for the analysis of array CGH data. Bioinformatics, 23, 657-663. [3] Hupé, P., Stransky, N., Thiery, J., Radvanyi, F. & Barillot, E. (2004) Analysis of array CGH data: from signal ratio to gain and loss of DNA regions. Bioinformatics, 20, 3413–3422.

199 ‹‹- Research Activities of Individuals Research Activities on Particle Physics Phenomenology

Kingman Cheung (Department of Physics, National Tsing Hua University; email: [email protected]) Center scientist, 2006/11/1~2008/10/31, 2009/2/1~now

have been in the Center as a Center bump-like structures. Scientist since November 2006. I am also In the work [1], we point out that the excess in the convener for the focus group on the LHC the ATIC data in fact consists of 1-peak plus Physics. My research area is in particle physics 1-hump structure. The peak is from 300-800 GeV phenomenology. In the following, I highlight while the bump from 80-300 GeV. A possible some works done in 2009. explanation is that the dark matter particle in the Introduction Universe undergoes both annihilation and decay. The annihilation gives rise to the peak around 600 The Large Hadron Collider (LHC) is going to GeV while the decay is responsible for the small start at the end of 2009. It will be the place for the bump around 80-300 GeV. The resulting positron next big discovery. More than half of the fraction observed at PAMELA is a combination of resources in high energy community will be put annihilation and decaying contributions. Through into it. Together with other planned cosmology a χ2 analysis we show that the fitting using a experiments, testing new ideas beyond the single mode (either annihilation or decay) is far standard model (SM) will be the major activities less satisfactory than the double mode (both in the next 10–20 years. My role is to link up annihilation and decay). The study shows that a theory and experiments. In the last year, I have dark matter particle of about 640 GeV with a accomplished a number of works on monochromatic annihilation spectrum and a soft supersymmetry, Higgs physics, dark matter, and decaying spectrum is the best simultaneous fit to cosmology. In the following, I highlight a few the PAMELA and ATIC data. In the figure, we topics that I feel very exciting. show the fits to the data of PAMELA and ATIC. Dark Matter Beyond the MSSM Dark matter has almost been confirmed by a An interesting scenario is the Higgsino-like number of cosmological and astrophysical LSP, which can arise from a number of observations. It is vital for structure formation supersymmetry breaking models, e.g., focus-point and make for the mass difference between matter supersymmetry models or whenever the µ and baryonic matter observed by WMAP. parameter is much smaller than the Bino and However, the nature of dark matter is totally Wino masses. In the minimal supersymmetric unknown, except for its nonbaryonic nature. standard model (MSSM), the Higgsino-LSP Recently, there are a number of astrophysical scenario implies nearly-degenerate Higgsino experiments hinting the signals of dark matter states: Coannihilation is too efficient so that the annihilation, notably PAMELA, ATIC, and observed CDM relic density requires a rather FERMI-LAT. The PAMELA Collaboration has heavy Higgsino state with mass around 1--1.2 reported an unexpected rise of positron fraction at TeV. Moreover, the mass degeneracies between the energy range of 10-100 GeV, unlike the ~ 0 the LSP (χ 1) and the lighter chargino/second- power-law falling background. However, similar ~ ± ~ 0 lightest neutralino (χ 1/χ 2) generate too soft decay enhancement of the anti-proton flux was expected products for detecting the states but not seen by PAMELA provides a challenging ~ ± ~ 0 χ 1 and χ 2 at the LHC. Thus, the Higgsino-LSP puzzle. The ATIC data showed an excess of in the MSSM posts a difficult scenario at the galactic cosmic-ray electrons/positrons at energies LHC. of 300 - 800 GeV, showing a peak-like and a

Research Activities of Individuals -›› 200 Iquarkonium We may encounter some new physics that we really do not expect, e.g.,unparticle proposed in 2007. The new physics proposed is the existence of a new strongly interacting nonabelian SU(3)

sector with the mass of the new fermions MQ' >> Λ' of the new sector. This sector is similar to the usual QCD but without the presence of light quarks. It is therefore very different from the usual QCD phenomenologically. In a work [3], we studied the phenomenology of such a scenario

with Λ' < ΛQCD and the mass of the new fermions, aka iquarks, is O(100) GeV. Phenomenology of this hypothetical QCD can be drastically different from the real world where light quarks do exist and one must have to worry about the spontaneous chiral symmetry breaking. For instance, heavy quarks are connected by unbreakable long and stable string flux tube since there is no light quark pairs popped up from the vacuum as the heavy quarks are being pulled apart. The size of the string flux tube is of order -1 In a work [2], we showed that the modest Λ' and it can be macroscopic for 100 eV ≤ Λ' ≤ 2 10 keV, or mesoscopic for 10 keV ≤ Λ' ≤ MeV, or addition of a dimension-5 λ(HuHd) /M to the MSSM superpotential, a scenario beyond MSSM microscopic for MeV ≤ Λ'. In general, one also (BMSSM) alleviates the difficulties of the assume Λ' is smaller than the ΛQCD such that the Higgsino-LSP scenario. It has been discussed that new color degree of freedom bears the name non-renormalizable and high-dimensional infracolor (IC). operators in new physics models can yield In the macroscopic Λ' scenario that once the important consequences in low energy ǪǬ is produced, they would be linked by a long phenomenology. This dimension-5 term, string roaming inside the detector. The infracolor 2 λ(HuHd) /M, lifts up the degeneracy between the dynamics can allow the ǪǬ bound state to survive ~ 0 ~ ± ~ 0 states χ 1 and χ 1/χ 2, thus enhancing the discovery for distances of order centimeter and preventing potential of the chargino and neutralino decays them from annihilation. In the mesoscopic Λ' with more energetic charged leptons or pions than scenario, the ǪǬ pair will appear as a single entity the decays in the MSSM. In addition, the inside the detector. On the other hand, if Λ' is ~ ± ~ 0 coannihilation of the LSP with χ 1 or χ 2 is reduced microscopic, the ǪǬ pair will lost most of their substantially such that a light Higgsino-LSP with a kinetic energy and angular momenta by emitting mass around 100 GeV can accommodate the iglueballs and/or light QCD hadrons like pions WMAP data on the CDM relic density. before annihilation. In the latter case in which Furthermore, the direct detection can be brought iquarks are QCD-colored, it leads to a hadronic below the current experimental limits due to fireball along with the other SM decay products of heavier Higgs boson mass. Thus, the BMSSM the iquarkonium. poses a lot of interesting consequences, which are Iquarks in the above model can be copiously due to the presence of higher dimensional terms in produced at the LHC, not via normal QCD the theory. Further investigations on other aspects interactions, but via electroweak interactions. The are also vital to test such higher dimensional iquarks are stable with respect to the collider time terms. scale, and linked by a string. Depending on the value of Λ' the iquarks will lose energy by

201 ‹‹- Research Activities of Individuals emitting iglueballs and bremsstrahlung until the iquark pair linked by the string come together and form a iquarkonium. The life time of the iquarkonium then depends on the annihilation rates into SM particles. In accord with the normal quarkonium, the life time of iquarkonium is inversely proportional to the square of the wave- function at the origin. The life time and decay patterns of the iquarkonium can therefore provide useful information about the quantum numbers of iquarks and the dynamics of the new strong interacting gauge group. Inflation Chia-Min Lin and I have worked on a number of papers on inflation models. Current data from WMAP have put cosmology into a precision regime, which can discriminate various inflation models or put severe constraints on models. We have considered a number of models in these papers, like hilltop inflation models, supernatural inflation models, D-term inflation, and supernatural A-term inflation models. I will skip the details here due to space limitation.

References [1] K. Cheung, P.Y. Tseng and T. C. Yuan, Phys. Lett. B 678, 293 (2009). [2] K.Cheung, S. Y. Choi and J. Song, Phys. Lett. B 677, 54 (2009). [3] K. Cheung, W. Y. Keung and T. C.Yuan, Nucl. Phys. B 811, 274 (2009). [4] C.M. Lin and K. Cheung, JCAP 0903, 012 (2009); JCAP 0906, 006 (2009); Phys. Rev. D79, 083509 (2009).

Research Activities of Individuals -›› 202 Research Activities on Quantum Information Science

Chung-Hsien Chou (Department of Physics, National Cheng Kung University, email: [email protected]) Center scientist, 2007/8/1~2009/7/31

n 2009 my research activity in NCTS has the larger a is, the shorter the disentanglement been on quantum information science and time. Finally, in the non-Markovian regime, the particle physics. The work on quantum strong impact of vacuum fluctuations experienced information science is quantum entanglement locally by each detector destroys their dynamics in relativistic motions and macroscopic entanglement right after the coupling is switched quantum phenomena. The work on particle on. physics is about physics beyond the standard Currently, we are now studying the model and cosmology. decoherence and disentanglement issues from the So far most of the discussions on quantum angle of quantum fields in curved spacetime. entanglement dynamics are non-relativistic and Some pioneer work had been done about with an implicit assumption that the background decoherence in particle creation processes, and we spacetime is globally Minkowski. In the work[1] are focusing on the evolution of quantum collaborated with Dr. S.Y. Lin at NCTS and Prof. entanglement in particle creation which have not B.L. Hu of UMD, we started to study the been explored in detail. We are considering the entanglement dynamics of two harmonic entanglement dynamics of particle creation in flat oscillators coupled to a background field with one spacetime under changing background field in uniform acceleration. This is an important first[2] and will move to more interesting case for ingredient for the establishment of relativistic dynamical background spacetime. quantum information theory. In our Recently I am also interested in the polariton nonperturbative treatment, the field will be Bose-Einstein condensate(BEC). Polaritons are evolving with the detectors as a combined close quasiparticles formed from electronic excitations system. coupled to photons in a microcavity. A number of The results from our calculations show that the BEC-like effects have been observed in this type interaction between entangled UD detectors and of system, including bimodal momentum-space the field does induce quantum disentanglement distribution with a narrow peak at zero between the two detectors. We found that the momentum, spatial condensation in a macroscopic disentanglement time is finite in all cases studied, trap, long-range off-diagonal order, existence of namely, there is no residual entanglement at late quantized vortices, linear Bogoliubov excitation times for two spatially separated detectors, one spectrum, and flow without dispersion. The stationary and another uniformly accelerating, in remarkable feature is that the polariton condensate (3+1)D Minkowski space. Around the moment of is not in thermal equilibrium however there are so full disentanglement there may be some short- many canonical features of Bose-Einstein time revival of entanglement within a few periods condensate can still be onserved in polariton of oscillations of the detectors (equal to the condensate. We are applying non-equilibrium field inverse of their natural frequency). In the theory methods to treat this macroscopic quantum ultraweak coupling limit, the leading-order phenomena. behavior of quantum entanglement in Minkowski During this year I also did some work on time is independent of Rob's proper acceleration particle physics. a . When a gets sufficiently large, the disentanglement time from Alice's view would be There are some solid evidences for the physics longer for a larger a. From Rob's view, however, beyond the Standard Model (SM) of particle

203 ‹‹- Research Activities of Individuals physics. One is the observations of neutrino charged scalars and phase space suppression of oscillations which has established that neutrinos the three body decay. Finally, the possibility of have very small masses. The low energy low-scale leptogenesis can be achieved if the accelerator experiment of the muon anomalous hierarchical Yukawa couplings among the new magnetic moment also gives another hint for the particles are satisfied. This scenario can be tested physics beyond the SM. Besides that there are also at LHC and/or future experiments. Currently we evidences from early Universe cosmology and are working on some phenomenological astronomy: the existence of dark matter and implications of the model on cosmology. matter-antimatter asymmetry of the Universe. The observed baryon asymmetry of the Universe can not be explained within the SM with one CP violating phase. Despite the great success of References standard big-bang nucleosynthesis, it has been [1] S.Y. Lin, C.H. Chou, and B.L. Hu, noted that the prediction for the ratio of 7Li/H and Disentanglement of two harmonic oscillators the isotopic ratio 6Li/7Li do not agree with current in relativistic motion, Phys. Rev. D 78, observations, called the "lithium problems". They 125025(2008). do not have an astrophysical solution in a [2] B.L. Hu , C.H. Chou, and S.Y. Lin, in complete manner at present. preparation. In the work[3] done in collaboration with Dr. [3] C.S. Chen, and C.H. Chou, Neutrino masses, C.S. Chen at NCKU, we try to address all of these muon g-2, dark matter, lithium problem, and issues within a single framework. Our model is an leptogenesis at TeV-scale, extension of the radiative seesaw mechanism of arXiv:0905.3477[hep-ph], submitted to Phys. neutrino mass with extra scalars and leptonic Lett. B. fermions. By imposing a Z2 symmetry, all the new particles can only appear in pairs through the

loops due to the Z2-odd parity assignment. The neutrino masses can be generated via one-loop effects at the TeV scale, in additional to the loop suppression factor the tiny neutrino mass scale is controlled by the mixing between charged scalars in our scenario. Similar mechanism will also contribute to muon anomalous magnetic moment which is easily fitted into the current deviation between the experimental data and SM prediction.

The lightest neutral Z2-odd particle provides the dark matter candidate in our model. The model also contains a long-lived charged particle requested by the scenario of CBBN where the long lifetime is due to the small mixing between

Research Activities of Individuals -›› 204 Research Activities on Strings

Kazuyuki Furuuchi (email: [email protected]) Staff scientist, 2007/8/1~present

n this academic year I studied M-theory I also made another related investigation on branes based on the BLG model of the M5-brane: An action of a 5-brane was multiple membranes. M-theory is a hypothetical constructed by Ho-Imamura-Matsuo-Shiba by theory which is expected to provide unified starting from the BLG model and choosing the description of five types of ten-dimensional Nambu-Poisson bracket as the Lie 3-algebra, then superstring theory. However, only some parts of expanding around certain background. They its structure in some specific limits are currently conjectured that it is related to previously understood. One of the expected features of constructed M5-brane theory in a constant three- M-theory is that supersymmetric membranes and form background via a generalization of the so 5-branes, extended in 2 and 5 spatial directions called Seiberg-Witten map. To make a step respectively (we will call them M2-branes and forward for the proof of this conjecture, in Ref. M5-branes, respectively), are the fundamental [3], with Tomohisa Takimi (NTU), I constructed building blocks of the theory. In the case of supersymmetric string-like soliton solutions of the D-branes which played crucial roles in the 5-brane action of Ho et. al. in the lowest order in understanding of non-perturbative aspects of the expansion of a deformation parameter which is string theory, the Lie algebra structure of multiple related to the three-form background. This D-brane system was a characteristic new feature. solution was compared with the string soliton of From this experience, we expect that if we find the previously known M5-brane using the the characteristic algebraic structure of multiple Seiberg-Witten map, and we found an agreement M2-brane system, we will understand M-theory at this order. This result provides a non-trivial better. From the end of 2006 to the end of 2007, support for the conjecture of Ho et. al., and sheds Bagger-Lambert and Gustavsson constructed a insights into the theory of M5-branes. model for multiple super-membranes which has a novel gauge symmetry based on Lie 3-algebra (Filippov n algebra with n =3), a natural extension References of the Lie algebra. Last academic year I studied [1] Kazuyuki Furuuchi, Sheng-Yu Darren Shih, the space-time supersymmetry algebra of the Tomohisa Takimi, "M-Theory Superalgebra Bagger-Lambert-Gustavsson model (BLG model) From Multiple Membranes" JHEP 0808:072 with Sheng-Yu Darren Shih (NTU, at the time) (2008). and Tomohisa Takimi (NCTU, at the time). The conclusion was that though the BLG model is not [2] Kazuyuki Furuuchi and Dan Tomino, manifestly space-time supersymmetric, it actually "Supersymmetric reduced models with a has a symmetry which is closely related with the symmetry based on Filippov algebra," JHEP space-time supersymmetry. This result suggests 0905:070 (2009). that there exists some space-time covariant [3] Kazuyuki Furuuchi and Tomohisa Takimi, formulation of the BLG model. To understand this "String solitons in the M5-brane worldvolume point, in Ref. [2], together with Dan Tomino at with a Nambu-Poisson structure and Seiberg- NCTS, I constructed simple models which has a Witten map," JHEP 0908:050 (2009). symmetry based on the Lie n-algebra, and classified the dimension of the space-time in which the model is manifestly space-time supersymmetric. This investigation is also motivated as a search for an extension of the type IIB matrix model which was proposed as a constructive definition of type IIB superstring theory, and which is based on the Lie algebra. We comment on an interesting interplay between Lie n-algebra symmetry and supersymmetry, which is an analogue of what happens in the type IIB matrix model.

205 ‹‹- Research Activities of Individuals Research Activities on Strings

Takayuki Hirayama (email: [email protected]) Postdoctoral researcher, 2007/9-/1~present

have been working on non perturbative describes the interactions between quarks and effects of string theory. I have published gluons. Since the interaction becomes strong in two papers with my collaborators in the academic low energy, it is difficult to analyze. In low year of 2008. energy, the chiral symmetry is dynamically broken by the quark condensate, and quarks make In the paper [1], I have analyzed the so-called composites, i.e. mesons and baryons. These Bagger-Lambert theory which is expected to be a dynamics cannot be computed from perturbative low energy effective theory of multi-membranes QCD approach. Therefore it is important to find in M-theory. String theory is defined another approach. In string theory, there is a perturbatically and a non-perturbative definition conjecture which claims the equivalence between of string theory is expected be a theory of a string theory or supergravity on a curved space membrane in eleven dimensional spacetimes, and a quantum field theory without gravity like M-theory. (string theory is a theory of string in ten QCD. The example which have been studied dimensional spacetimes.) We only have poor intensively is the duality between Type IIB string knowledge of M-theory, and do not even have an theory in a space of 5 dimensional Anti-de Sitter action! Recently, Bagger and Lambert proposed space times 5 dimensional sphere and the four an action in three dimensions which possesses the dimensional N=4 supersymmetric Yang-Mills properties of multi-membranes. Thus I and my theory. This duality is a weak-strong duality in a collaborator analyzed this action and studied a sense that a weak string coupling region of Type scattering of membranes perturbatically in order IIB string theory is dual to a strong gauge to compute the potential between the membranes. coupling region of Yang-Mills theory. Therefore This potential must be identified Newton potential this AdS/CFT correspondence offers a quite and then we can read out the target spacetime powerful tool of computing a strongly coupled dimensions from the power low of potential. This gauge theory from a weakly coupled gravity study is important for checking whether Bagger- theory. I have been challenging to construct the Lambert theory is really a theory of multi- gravity dual description of QCD. One successful membranes in eleven dimension ( M-theory is model was constructed by Sakai and Sugimoto defined in eleven dimensions). Our finding is that which is based on D-branes in string theory. the target space dimension is ten, not eleven [1]. Though their model is successful, the pion, which We find that the membrane propagating between is associated with the chiral symmetry breaking, is two membranes always wrap on one space massless although the pion has a mass about 140 direction so that this direction cannot be sensed. Mev. I and my collaborators studied how to Therefore Bagger-Lambert theory does not introduce the pion mass, i.e. the quark mass in the capture all the properties which multi membrane academic year 2007. In the paper [2], we then should have, although it really has possessed some studied how much the masses of mesons and of them. We also discussed in the paper that the baryons are shifted by the presence of quark missing one space direction can be probed by non- masses. We gave the formulae to compute their perturbative process (monopole instanton). values and compared the results with the data In the paper [2], I have studied quark mass from lattice calculations. We found that our values dependence of hadrons using a holographic dual are consistent with lattice results and thus our gravitational description of QCD (Quantum model is a good candidate for the holographic Chromo Dynamics). QCD is a gauge theory which dual of QCD. Since the model is known to have

Research Activities of Individuals -›› 206 many other unsuccessful points, it is important to improve our model.

References [1] Membrane scattering from Bagger-Lambert theory. Takayuki Hirayama, Dan Tomino. Published in JHEP 0908:071,2009. e-Print: arXiv:0812.1866 [hep-th] [2] Quark Mass Dependence of Hadron Spectrum in Holographic QCD. Koji Hashimoto, Takayuki Hirayama, Deog Ki Hong. Submitted to PRD. e-Print: arXiv:0906.0402 [hep-th]

207 ‹‹- Research Activities of Individuals Research Activities on Symmetry Breaking in Hadron Physics

Hiroaki Kohyama (email: [email protected]) Postdoctoral researcher, 2008/8/1~present

008 in NCTS is devoted to the study on For the purpose to study the critical point, we symmetry breaking in hadron physics. perform numerical analysis by varying the current Quarks and gluons are believed to be the quark masses. In the 3 flavor (up, down and elementary particles which can not be divided strange) NJL model, the phase transition in the anymore. Under the cold and dilute environment, massless limit is of the first order, being the quarks and gluons are confined into hadrons and consequence of symmetry. On the other hand, the never be observed as free particles. However, at transition for intermediate quark masses is the high temperature, quarks and gluons can get crossover due to the effect of masses which enough energy to escape from hadron confinement explicitly break the chiral symmetry. This defines and they can be free particles. This state is called the critical boundary which separates the first quark gluon plasma which is seen at the extreme order transition region and the crossover region. condition in high energy experiments. The drastic This boundary is important because it determines change of sate of this kind is called the phase the order of the phase transition at the physical transition which is closely related to the current quark masses. In Ref.[1], we have studied phenomena of symmetry breaking. In the case of the critical boundary at finite temperature and\or confinement-deconfinement phase transition, density by using the extended NJL model with symmetry is broken in confinement phase and it is density dependent UA(1) anomaly. We found that restored in deconfinement phase. Thus the idea of the region of the first order phase transition the symmetry breaking is crucial key to shrinks according to the chemical potential at low understand the critical phenomena. chemical potential. The result obtained in our paper is consistent to the recent Lattice QCD In principle, all phenomena related to the studies. This may indicate that the QCD phase quarks and gluons should be described by the transition does not have the critical point, which Quantum Chromodynamics, the fundamental means that the phase transition is always the theory of quarks and gluons. The ultimate goal of crossover. QCD is to explain all strongly interacting phenomena for all energy scale, high and low. QCD is the asymptotically free theory and coupling strength becomes small at high energy, Reference which means that a perturbative calculation works [1] J.-W. Chen, K. Fukushima, H. Kohyama, K. well in high energy region. However it is difficult Ohnishi, U. Raha, UA(1) anomaly in hot and to perform a perturbative calculation due to large coupling constant in low energy region, and we dense QCD and the critical surface, Phys. usually have to rely on some effective models of Rev. D 80, 054012 (2009). QCD. The effective model that I studied in this year is the Nambu Jona-Lasinio (NJL) model. The NJL model has the same symmetry properties of QCD and successfully describes the chiral symmetry breaking at low temperature and density and its restoration at high temperature and\or density. It is also applicable to the study of the QCD critical point in the phase diagram with temperature and quark chemical potential. The QCD critical point is the point where the first order phase transition ends and the phase transition becomes the crossover above the critical temperature.

Research Activities of Individuals -›› 208 Research Activities on Particle Physics

Jae Sik Lee (email: [email protected]) Assistant research scholar, 2008/7/1~present

ike as in the previous years, my main The minimal supersymmetric model to achieve research activity during 2009 has been this goal is the Next-to-Minimal Supersymmetric concentrated on the phenomenology of the Standard Model (NMSSM) which adds one more Minimal Supersymmetric extension of the gauge singlet to the MSSM. We have made a team Standard Model (MSSM). But, I believe I will for the NMSSM phenomenology with explicit CP remember this year a little differently since I have violation. The team consists of Prof. Kingman studied several topics which are not the typical Cheung, Mr. Tie-Jiun Hou, Dr. Eibun Senaha, and MSSM ones. The list contains myself [2]. We have done the calculation of the Higgs mass spectrum and the mixing by including (i) Standard Model Higgs boson [1] the higher-order corrections beyond the one-loop (ii) Singlet extension of the MSSM [2] level and Mr. Hou presented the results at the (iii) Supersymmetric Nambu--Jona-Lasinio recent LHC workshop at NCKU, see the model [3] workshop homepage, http://phys.cts.ntu.edu.tw/ If I should choose the most important work of workshop/2009/981024LHCP/. We are going to mine in the year of 2009, it should be the work on develop this subject by including the low-energy reconstructing the SM Higgs boson at the LHC precision experiments to explain the matter- [1]. In the paper, we examine the prospect to antimatter asymmetry of our Universe. The measure the Higgs boson mass using the recently relevant LHC phenomenology is the most introduced kinematic variable, the M_T2-Assisted attractive in the coming years. On-Shell (MAOS) momentum. We show that the MAOS scheme provides a systematic Together with the members of the Physics approximation to the invisible neutrino momenta department of the National Central University, in in the Higgs-boson decay into a dileptonically which I had been affiliated before I came over to decaying W-boson pair. Through a full Monte NCTS (Hsinchu), we have studied a possibility of Carlo (MC) simulation, it is demonstrated that the dimension-five operators with strong couplings in MAOS Higgs mass distribution, constructed with the superpotential as an alternative origin of the the MAOS neutrino momenta, shows a clear peak particle masses [3]. We named the model at the true Higgs boson mass when an event cut Holomorphic Super Nambu--Jona-Lasinio Model selecting higher value of M_T2 is employed. Our (HSNJL) The approach provides a new direction results indicate that the MAOS Higgs mass can be for modeling dynamical symmetry breaking in a useful also for the discovery or exclusion of the supersymmetric setting. In particular, we adopt the Higgs boson in certain mass range. One of the idea to formulate a model that gives rise to the co-authors (Prof. Suyoung Choi) of the paper is an MSSM as the low energy effective theory with experimenter and he is now analysing the D0/ both Higgs superfields as composites. This work Tevatron data using the suggested method. This will mature in near future by including work has been done with my Korean colleagues comprehensive study of the model and exploring and this would consist part of a Ph.D thesis of the its full theoretical aspects. last author, Mr. Park. Other than the above non- or less-MSSM like Actually, the MSSM has a weak point known studies, we have published a paper on the electric as the mu problem. For a supersymmetric model and anomalous magnetic dipole moments of the to be phenomenologically viable, the size of the muon in the MSSM [4]. This work might be a mu parameter should be around the scale of 1 TeV. sequel to my previous comprehensive work on the

209 ‹‹- Research Activities of Individuals electric dipole moments in the MSSM [5]. In the collider, Phys. Rev. D 80, 073010 (2009) paper, we study the electric dipole moment [2] Kingman Cheung, Tie-Jiun Hou, Jae Sik Lee, (EDM) and the anomalous magnetic dipole Eibun Senaha, NMSSM Higgs sector with moment (MDM) of the muon in the CP-violating explicit CP violation, in preparation MSSM. We take into account the general one-loop [3] Dong-Won Jung, Otto C.W. Kong, Jae Sik graphs and the dominant two-loop diagrams. We Lee, Holomorphic Supersymmetric Nambu- improve earlier calculations by incorporating Jona-Lasinio Model, e-Print: arXiv:0906.3580 CP-violating Higgs-boson mixing effects and the [hep-ph] resummed threshold corrections to the Yukawa couplings of the charged leptons as well as that of [4] Kingman Cheung, Otto C.W. Kong, Jae Sik the bottom quark. The analytic correlation Lee, Electric and anomalous magnetic dipole between the muon EDM and MDM is explicitly moments of the muon in the MSSM, JHEP presented at one- and two-loop levels and, through 0906:020,2009. several numerical examples, we illustrate its [5] John R. Ellis, Jae Sik Lee, Apostolos Pilaftsis, dependence on the source of the dominant Electric Dipole Moments in the MSSM contributions. We have implemented the analytic Reloaded, JHEP 0810:049,2008. expressions for the muon EDM and MDM in an [6] J.S. Lee, M. Carena, J. Ellis, A. Pilaftsis, updated version of the public code CPsuperH2.0 C.E.M. Wagner, CPsuperH2.0: an Improved [6]. Computational Tool for Higgs On the other hand, together with my UK Phenomenology in the MSSM with Explicit colleagues, I studied the exotically decaying CP Violation, Comput.Phys. MSSM Higgs bosons at hadron colliders [7]. Commun.180:312-331,2009. Specifically, we suggest a new scenario for the [7] J.S. Lee, Y. Peters, A. Pilaftsis, C. search of strangephilic MSSM Higgs bosons at the Schwanenberger, Strangephilic Higgs Bosons Tevatron and the LHC, in which all neutral and in the MSSM, e-Print: arXiv:0909.1749 [hep- charged Higgs bosons decay predominantly into ph] pairs of strange quarks and into a strange and a [8] D0 Collaboration, V. Abazov et al., Search for charm quark, respectively. The proposed scenario charged Higgs bosons in top quark decays, is realized within a particular region of the MSSM e-Print: arXiv:0908.1811 [hep-ex] parameter space and requires large values of [9] Jae Sik Lee, Manifestations of CP Violation in tan(beta), where threshold radiative corrections the MSSM Higgs Sector, AIP Conf. are significant to render the effective strange- Proc.1078:36-41,2009 quark Yukawa coupling dominant. Experimental searches for neutral Higgs bosons based on the identification of b-quark jets or tau leptons may miss a strangephilic Higgs boson and its existence could be inferred indirectly by searching for hadronically decaying charged Higgs bosons. A part of the scenario has already been searched by D0 at the Tevatron [8]. Finally, I report my invited plenary talk to the 16th International Conference on Supersymmetry and the Unification of Fundamental Interactions (SUSY08) has been published as in Ref.[9].

References [1] Kiwoon Choi, Suyong Choi, Jae Sik Lee, Chan Beom Park, Reconstructing the Higgs boson in dileptonic W decays at hadron

Research Activities of Individuals -›› 210 Research Activities on Lattice Gauge Theory in Physics of the Large Hadron Collider

C.-J. David Lin (Institute of Physics, National Chiao-Tung University; email: [email protected]) Center scientist, 2009/2/1~2011/1/31

Introduction Dynamical electroweak symmetry breaking Walking technicolour is one of the candidates that generate electroweak symmetry breaking at Since I joined the NCTS in 2007, I have TeV scale without the need for the Higgs particles. been working on projects in physics It is a strongly-coupled gauge theory, hence lattice related to the Large Hadron Collider using large- gauge theory can play an important role in this scale numerical simulations in Lattice Gauge research avenue. In the walking-technicolour Theory. This is reflected in two main research scenario, the coupling constant in the gauge avenues that I am pursuing. First, I am studying theory increases over a range of scale when the the scenario of electroweak symmetry breaking energy is decreased, then it becomes "frozen". At via strongly-coupled gauge theories at TeV scale. the very low energy regime, it starts increasing Second, I am performing calculations for decay again, such that conformal symmetry and chiral amplitude of baryons containing a b quark, which symmetry are broken dynamically. The system is the main subject of the LHC-b experimental then develops an energy gap which generates the project. spectrum. Hardware The reason why such a scenario is required is due to the need to dynamically suppress the The start-up equipment fund for my position flavour-changing neutral currents (FCNC) in was granted in the summer of 2007, from the physics beyond the Standard Model. A walking National Science Council and Faculty of Sience, theory is likely to produce large anomalous National Chiao-Tung University. From August dimensions for the operators that generate the 2007 to December 2007, I played the main role in Standard Model fermion masses. This can then lift the purchase of a PC cluster using this start-up the scale at which flavour emerges, hence fund. The cluster was delivered between January suppress the FCNC. It is not easy even just to and April 2008. Now it contains twenty-six find a theory which has the "walking" feature and computing nodes. Each node has two quad-code dynamical symmetry breaking at low energy. CPUs and sixteen gigabites of memory (with error Exploratory result using the step-scaling method checking). Twenty-two of these nodes are was reported by Appelquist and collaborators connected via a Double-Data-Rate (up to 20 recently [1]. These authors calculated the coupling gigabits per second) infiniband switch. The other constant in the so-called Schroedinger functional four are on a gigabit network. In addition to the scheme for QCD-like theories with large numbers computing nodes, we have a six-terabite disc array of flavours. They discovered that the coupling for storage. constant would stop running for a range of scale in Recently, I started to set up facilities for high- some of these theories. However, the coupling performance computing using GPU. In November constant not physical, hence depends on the 2009, I organised a one-day NCTS (on NCTU renormalisation scheme in which it is calculated. campus) training course for programming skills Therefore it is important to check the claim by on such equipments. Appelquist et al. in at least another scheme.

211 ‹‹- Research Activities of Individuals 2 shows the quenched feasility study of the TPL scheme. Figure 3 exhibits the data in the case of 12 flavours, where x-axis is the lattice spacing (left-hand size is coarser), y-axis is proportional to the coupling constant and different symbols correspond to various lattice sizes. From this plot, it is evident that the long-distance regime may contain an infrared fixed point.

I have formed a collaboration with physicists in Professor Tetsuya Onogi's group at Osaka University. We are studying the scale dependence of the coupling constant in these theories iusing the Creutz-ratio scheme, as well as the Twisted- Polyakov-line (TPL) scheme. In the Creutz-ratio scheme, We fix the scheme by keeping constant the ratio between the Wilson-loop size and the lattice size. This specifies the scheme. We then perform calculations at various lattice sizes and extrapolate to the continuum limit at each step. The lattice size is the renormalisation scale in this procedure. Since this is a new scheme, we have performed exploratory numerical study of the Physics of the b-baryon coupling constant in the quenched prroximation for QCD and found that it worked well [2], since A b-baryon is composed of three valence it could reproduce the perturbative results in the quarks, namely, a b-quark and two light quarks. region where perturbation theory would apply. The rare decay channels in which a non-stranged Figure shows the result of this calculation, where b-baryon decays into a stranged baryon plus a the x-axis is the scale and the y-axis is the photon or a lepton pair are sensitive to new coupling constant. physics effects involving the mixing of quarks via right-handed coupling structure that is absent in the Standard Model. This structure cannot be probed by existing experiments performed with the B mesons which do not carry spin. With William Detmold and Matthew Wingate, I have set up a programme to pin down the relevant matrix elements in the above decay channel as our final goal. In our programme, we use the dynamical gauge configurations generated and kindly lent to us by the RBC Collaboration. The lattice size is 24-cube times 64, with lattice spacing around 0.1 fm. The 2+1 flavours of dynamical quarks in these RBC configurations are domain wall For the simulations with 12 flavours, we go for fermions. We also use the same fermions for our the TPL scheme, since the required lattice size is valence light quarks. For the heavy quark, we use smaller in this scheme, compared to the Creutz- the static approximation where the heavy-quark ratio scheme. From our preliminary result [3], mass is infinite. The most time-consuming step in there is evidence that the theory flows into an this programme is to generate light-quark infrared fixed point in this scheme as well. Figure

Research Activities of Individuals -›› 212 propagators. We have accumulated many such [2] E. Bilgici, A. Flachi, E. Itou, M. Kurachi, propagators using my PC cluster and other C.-J.D. Lin, H. Matsufuru, H. Ohki, T. Onogi computing resources in the USA. and T. Yamazaki, "A New scheme for the running coupling constant in gauge theories As the first step towards the calculation of rare using Wilson loops", Phys.Rev. decay matrix elements of b-baryons, we have D80:034507,2009. studied the spectrum of these baryons. In particular, we are investigating the light-quark [3] E. Bilgici, A. Flachi, E. Itou, M. Kurachi, mass dependence of the spectrum. There have C.-J.D. Lin, H. Matsufuru, H. Ohki, T. Onogi, been very few lattice calculations for the b-baryon E. Shintani and T. Yamazaki, "Search for the spectrum, and the parameters (quark mass, lattice IR fixed point in the twisted Polyakov loop volume, etc.) in our work are the closest to the scheme", arXiv:0910.4196 [hep-lat] (Lattice physical values. Figure 4 collects our results for 2009 proceedings). this spectrum calculation. It is shown that our [4] W. Detmold, C.-J.D. Lin and M. Wingate, results are largely compatible with experiments. "Bottom hadron mass splittings in the static This calculation has been published in Ref. [4]. limit from 2+1 flavour lattice QCD", Nucl. Phys.B818:17-27,2009. [5] S. Meinel, W. Detmold, C.-J.D. Lin and M. Wingate, "Bottom hadrons from lattice QCD with domain wall and NRQCD fermions", arXiv:0909.3837 [hep-lat] (Lattice 2009 proceedings).

We are also performing the same calculation using a different heavy-quark formulation. The result has been reported in Ref. [5]. At the same time, we are proceeding with calculations of various matrix elements. We have accumulated data for measuring the coupling amongst a vector B meson, a pseudoscalar B meson and a pion.

References [1] T. Appelquist, G. Fleming and E. Neil, "Lattice Study of Conformal Behavior in SU(3) Yang-Mills Theories", Phys.Rev. D79:076010,2009.

213 ‹‹- Research Activities of Individuals Research Activities on Spintronics

Hsiu-Hau Lin (Department of Physics, National Tsing Hua University; email: [email protected]) Center scientist, 2006/2/1~2010/1/31

n the past year (2008-2009), I have Appl. Phys. Lett 95, 082104 (2009) continued my research on low [C3] Jhih-Shih You, Wen-Min Huang and Hsiu- dimensional correlated systems (L) and Hau Lin spintronics (S) with publications listed below. Let Relativistic ferromagnetic magnon at the me briefly summarize our research results here zigzag edge of graphene and leave detail explanations for key findings in arXiv: 0901.4567 later paragraphs. Phys. Rev. B (Rapid Comm.) 78, 161404 On the low-dimensional correlated system (2008) side, we tried to address various physical [C4] Hsiu-Hau Lin, Toshiya Hikihara, Horng-Tay properties in low dimensional systems including Jeng, Bor-Luen Huang, Chung-You Mou the charge-density wave formation, conductance and Xiao Hu anomaly in carbon nanotubes and flat-band Ferromagnetism in armchair graphene freeomagnetism in armchair graphene nanoribbon. nanoribbon One of the most striking features we tried to arXiv: 0901.4177 investigate is symmetry restoration under Phys. Rev. B 79, 035405 (2009) renormalization group transformation. We devise [C5] J. E. Bunder and Hsiu-Hau Lin an elegant transformation to map the metallic Phase diagram of the metallic zigzag carbon zigzag carbon nanotube to a non-conventional nanotube two-leg ladder (without inter-leg hopping) and arXiv: 0803.3107 found an approximate SO(6) symmetry in the Phys. Rev. B 78, 035401 (2008) neutral sector. Pursuing the same direction, we [C6] J. E. Bunder and Hsiu-Hau Lin combine the techniques of the perturbative Generic short-range interactions in two-leg renormalization group and the non-perturbative ladders bosonization to obtain global phase diagram for arXiv: 0808.3297 zigzag carbon nanotube. As the interaction Phys. Rev. B 79, 045132 (2009) strength decreases into the weak-coupling regime, symmetry restoration emerges giving rise to [C7] Wen-Min Hunag and Hsiu-Hau Lin various non-trivial binding mechanism and also Identifying the pairing symmetry in sodium excitation degeneracy, which may help us to cobalt oxide by Andreev edge states: understand how non-conventional pairing arises in theoretical analysis strongly correlated systems in low dimensions. arXiv: 0901.4570 Phys. Rev. B 78, 224522 (2008) [C1] Wen-Min Huang, Jian-Ming Tang and Hsiu- [C8] Po-Yao Chang, Wen-Min Huang and Hsiu- Hau Lin Hau Lin Power-law singularity in the local density of Impurity-induced conductance anomaly in states due to the point defect in graphene zigzag carbon nanotubes arXiv: 0901.4141 J. Phys.: Conf. Ser. 150, 022007 (2009) Phys. Rev. B (Rapid Comm.) 80, 121404 (2009) [C2] Po-Yao Chang and Hsiu-Hau Lin [C9] Yen-Chen Lee and Hsiu-Hau Lin Conductance through a single impurity in Flat-band ferromagnetism in armchair the metallic zigzag carbon nanotube graphene nanoribbons

Research Activities of Individuals -›› 214 arXiv: 0901.4387 coupling mediated by itinerant carriers with J. Phys.: Conf. Ser. 150, 042110 (2009) different Fermi surfaces On the spintronics part, we applied the arXiv: 0901.4577 developed self-consistent Green’s function Phys. Rev. B 79, 045315 (2009) approach to nanoscale junctions and find the [S6] Hung-Ta Lin, Wei-Ji Huang, Shuo-Hong carrier-mediated exchange coupling strongly Wang, Hsiu-Hau Lin and Tsung-Shune Chin depends on the topology of the Fermi surface Carrier-mediated ferromagnetism in topology. We also collaborate with p-Si(100) by sequential ion-implantation of experimentalists to see whether the theoretical B and Mn predictions can be verified. In p-type Si film J. Phys.: Condensed Matter 20, 095004 implanted with B and Mn ions, the theoretical (2008) predictions are in qualitative agreement with the [S7] Wen-Min Huang, Hsin-Hua Lai, Cheng- experimental data. Furthermore, in a recent Hung Chang and Hsiu-Hau Lin collaboration, we were able to achieve Carrier-mediated exchange coupling and quantitative explanation of the magnetization Fermi surface topology (invited article) curve in amorphous Si film doped with Cr. It is Int. J. Mod. Phys. B 22, 88 (2008) rather remarkable that the quantitative agreement between the theory and the experiment can be Correlation effects of single-wall carbon achieved by only one fitting parameter! nanotubes in weak coupling Hsiu-Hau Lin [S1] Meng-Shian Lin, Hao-Cheng Hou, Yun- cond-mat/9709166 Chung Wu, Po-Hsiang Huang, Chih-Huang Phys. Rev. B 58, 4963 (1998) Lai, Hsiu-Hau Lin, Hong-Ji Lin and Fan- Hsiu Chang Effects of perpendicular interlayer coupling strength on canting angles of TbCo- sublattice magnetization Phys. Rev. B (Rapid Comm.) 79, 140412 (2009) [S2] S. Yeo, J. E. Bunder, Hsiu-Hau Lin, Myung- Hwa Jung and Sung-Ik Lee Concurrent magnetic and metal-insulator transitions in Eu1−xSmxB6 single crystals arXiv: 0901.4384 Appl. Phys. Lett. 94, 042509 (2009) [S3] Jia-Hsien Yao, Hsiu-Hau Lin and Tsung- Shune Chin Room Temperature Ferromagnetism in Cr-doped Hydrogenated Amorphous Si Films arXiv: 0901.4123 Appl. Phys. Lett. 92, 242501 (2008) [S4] J. E. Bunder and Hsiu-Hau Lin Ruderman-Kittel-Kasuya-Yosida interactions A spin liquid phase predicted in carbon on a bipartite lattice nanotubes more than a decade ago is recently arXiv: 0908.1432 spotted by experimental groups at Cal Tech and Phys. Rev. B 80, 153414 (2009) Columbia. Their experimental findings were [S5] Hsin-Hua Lai, Wen-Min Huang and Hsiu- published in Science 323, 106 (2009). Hau Lin Previous theoretical investigations show that Spatial trends of noncollinear exchange electronic interactions in carbon nanotubes at half

215 ‹‹- Research Activities of Individuals filling lead to gaps in charge and spin sectors near the edge of graphene. Meanwhile, it also without breaking the translational invariance. The indicates that the interplay between the electronic ground state is described by the so-called spin interactions and the open boundaries plays an liquid with various interesting properties. Using important role in relativistic systems. transport spectroscopy, an energy gap exisits in nominally metallic carbon nanotubes and also Ferromagnetism in armchair graphene occurs in addition to the band gap in small-band- nanoribbon gap nanotubes, indicating that carbon nanotubes Hsiu-Hau Lin, Toshiya Hikihara, Horng-Tay Jeng, Bor-Luen are never metallic. They also observed neutral Huang, Chung-You Mou and Xiao Hu arXiv: 0901.4177 excitations within the gap as predicted for this Phys. Rev. B 79, 035405 (2009) state. These experimental findings underline nanotubes' exceptional capabilities for use in studying correlated electron phenomena in one dimension. Relativistic ferromagnetic magnon at the zigzag edge of graphene Jhih-Shih You, Wen-Min Huang and Hsiu-Hau Lin arXiv: 0901.4567 Phys. Rev. B 78, 161404(R) (2008)

Due to the weak spin-orbit interaction and the peculiar relativistic dispersion in graphene, there are exciting proposals to build spin qubits in graphene nanoribbons with armchair boundaries. However, the mutual interactions between electrons are neglected in most studies so far and thus motivate us to investigate the role of electronic correlations in armchair graphene nanoribbon by both analytical and numerical methods. Here we show that the inclusion of Relativity ensures every particle is mutual repulsions leads to drastic changes and the accompanied by its own anti-particle. Well, when ground state turns ferromagnetic in a range of arriving at the edge of the universe, we found that carrier concentrations. Our findings highlight the these relativistic twins may break apart. While it is crucial importance of the electron-electron tough to make such a long trip in our universe, it interaction and its subtle interplay with boundary is relatively easy to explore all sorts of relativistic topology in graphene nanoribbons. Furthermore, effects in graphene, a recently discovered material since the ferromagnetic properties sensitively made of single-layer graphite in your pencils. depends on the carrier concentration, it can be Interactions among electrons in graphene give rise manipulated at ease by electric gates. The to a particle named “magnon”, which describes resultant ferromagnetic state with metallic how spin disturbances propagate in the two- conductivity is not only surprising from an dimensional flatland. Remarkably, we spot a new academic viewpoint, but also has potential type of magnon near the edge of graphene with applications in spintronics at nanoscale. lower excitation energy compared with their cousins in the bulk. It is surprising that the edge Identifying the pairing symmetry in magnon does not have antiparticle while its sodium cobalt oxide by Andreev edge cousins in the bulk always appear in twin pairs as states: theoretical analysis predicted by relativity theory. This highlights the Wen-Min Hunag and Hsiu-Hau Lin importance to investigate the relativistic effects arXiv: 0901.4570 Phys. Rev. B 78, 224522 (2008)

Research Activities of Individuals -›› 216

We study the Andreev edge states with different pairing symmetries and boundary topologies on semi-infinite triangular lattice of sodium cobalt oxide. A general mapping from the two dimensional lattice to the one dimensional tight-binding model is developed. It is shown that the phase diagram of the Andreev edge states depends on the pairing symmetry and also the boundary topology. Surprisingly, the structure of the phase diagram crucially relies on the nodal points on the Fermi surface and can be explained by an elegant gauge argument. We compute the momentum-resolved local density of states near the edge and predict the hot spots which are measurable in Fourier-transformed scanning tunneling spectroscopy.

217 ‹‹- Research Activities of Individuals Research Activities on Relativistic Quantum Information

Shih-Yuin Lin (Department of Physics, National Cheng Kung University; email: [email protected]) Assistant research scholar, 2006/8/1~31, 2009/7/31

y research on relativistic quantum interference pattern of the relative degree of information (RQI) in 2009 is an extension entanglement (compared to those at spatial of my work in 2008 [1]. I study the detailed infinity) develops a parametric dependence on d. entanglement dynamics of atoms or Unruh-DeWitt The detectors separated at those d with a stronger (UD) detectors (quantum objects localized in relative degree of entanglement enjoy longer space with internal degrees of freedom such as disentanglement times. harmonic oscillators) moving in a relativistic Taking advantage of our exact, analytic quantum field. expressions of correlators, we can monitor the Our detector-field model is an open quantum behavior of the detectors from initial moment all system, in which properties of the environment the way to very late times. We find that the (the quantum field) will affect the dynamics of the detectors always disentangle at late times in the system (the detectors) via coupling, which could cases with weak coupling and large separation. depend on the position of the detectors. One of For sufficiently small d, on the other hand, the two those properties is the intrinsically relativistic detectors can have residual entanglement at late nature of the quantum field, in which physical times even if they were initially in a separable information propagates at a finite speed. Issues of state, while for d a little larger, there could be causality are unavoidably involved in our models. transient entanglement created by mutual influences. Such transient entanglement can have Since 2005 I have done a series of work on the a very long life-time which could not be handled detector-field system in collaboration with Prof. by conventional numerical calculations. Bei-Lok Hu at University of Maryland and Prof. Chung-Hsien Chou at National Cheng Kung In [2] we see no evidence of entanglement University. To see the dependence on positions of creation for initially separable states before each the detectors and the effect of retarded mutual detector started to establish causal connection influences mediated by the quantum field, we with the other, while there have been some authors applied our well developed techniques to the cases [3] claimed that quantum entanglement between with two Unruh-DeWitt detectors at rest, without two causally disconnected atoms can be created. any direct interaction, and separated at a distance These are not contradictory claims because the d [2]. This simple model when analyzed properly setups of the problem are not exactly the same. To in quantum field theory shows many interesting definitely answer whether there is entanglement facets and helps to dispel some misunderstandings creation between two causally disconnected of entanglement dynamics. We find that there is objects, we further study the entanglement spatial dependence of quantum entanglement in dynamics of two uniformly accelerated Unruh- the stable regime due to the phase difference of DeWitt detectors moving back-to-back in the field vacuum fluctuations the two detectors experience, vacuum [4]. In this setup each detector never together with the interference of the mutual enters the other's light cone, so they cannot influences from the back-reaction of one detector exchange classical information and energy. For on the other. When two initially entangled two detectors moving in this way, our exact results detectors are still outside each other's light cone, show that quantum entanglement between the the entanglement oscillates in time with amplitude detectors can be created by the quantum field dependent on spatial separation d. When the two under some specific circumstances. Prior result detectors begin to have causal contact, an derived using the time-dependent perturbation

Research Activities of Individuals -›› 218 theory with extended integration domain is shown to be a limiting case of our exact solutions at some References specific moment. We find that the created [1] S.-Y. Lin, C.-H. Chou and B. L. Hu 2008, entanglement lasts only a finite duration, and Disentanglement of two harmonic oscillators always disappears at late times in this setup. In the in relativistic motion, Phys. Rev. D 78, weak coupling limit, this entanglement creation 125025 [arXiv:0803.3995] (selected for the can occur only if the initial moment is placed January 2009 issue of Virtual Journal of early enough and the proper acceleration of the Quantum Information). detectors is not too large or too small compared to [2] S.-Y. Lin and B. L. Hu 2009, Temporal and the natural frequency of the detectors. The spatial dependence of quantum entanglement entanglement dynamics here depend on the from a field theory perspective, Phys. Rev. D fiducial time, so they are intrinsically non- 79, 085020 [arXiv:0812.4391] (selected for Markovian. In the strong coupling and high the May 2009 issue of Virtual Journal of acceleration regime, vacuum fluctuations Quantum Information). experienced by each detector locally always dominate over the cross correlations between the [3] B. Reznik 2003, Found. Phys. 33, 167; J. D. detectors, so entanglement between the detectors Franson 2008, J. Mod. Opt. 55, 2117. will never be generated. [4] S.-Y. Lin and B. L. Hu 2009, Entanglement creation between two causally disconnected Based on these findings, we propose a objects, submitted to Phys. Rev. D. conjecture on the entanglement creation time, i.e., that quantum entanglement between two spacelike separated localized objects interacting only through a common quantum field cannot be created any earlier than the earliest possible moment for a third localized object (a spectator) begins to establish causal contact with both detectors. Currently I am considering some more general cases, including those with the quantum field initially in a thermal state at finite temperature, and the detectors initially in a separable Gaussian mixed state and/or moving in time-varying accelerations. Besides, I am also looking at the dynamics of entanglement in cosmological particle production and in parametric oscillators.

219 ‹‹- Research Activities of Individuals Research Activities on Strings

Dan Tomino (email: [email protected]) Assistant research scholar, 2008/8/1~present

n 2008 my research activities in NTCS spacetime with one compactified direction when are following: 1-loop calculation is available. Our calculation produced a consistent result with such 1. Study of membrane theory with Lie observation. 3-bracket structure And I proposed a new reduced model with Lie There are five-kind of superstring theories 3-bracket structure with Dr. Kazuyuki Furuuchi of formulated in ten dimensional spacetime which NTCS [2]. These models have a fermionic have been known. Nowadays it is widely believed symmetry. Combining this symmetry with other that all of them are different aspects of an guage symmetry and translational symmetry of unknown theory, this is the unified theory of this model, they can form supersymmetry which superstring. It is also well known that if this target space is 2+2 dimensional flat space. Indeed, conjecture is true then this unified theory should when dimension of Lie 3-albgebra is infinite, one have descriptions not only by string in ten can see that this model is classically equivalent to dimensional spacetime but also by membrane in the Green-Schwarz supermembrane in 2+2 eleven dimensional spacetime. From this reason dimensional flat space. Thus our reduced model finding suitable membrane theory has been can be a regularization of continues membrane by interesting problem, because we have known little Lie 3-algebra. Carry out path integral of this about whole picture of the unified theory of super reduced model would give the quantized string. Recently Bagger and Lambert proposed an membranes. To develop the technique in order to action (BL model) which describes low energy carry out the path integral will be a future subject dynamics of multiple membranes. In several of investigation. points of view, their action is remarkable. There have been no actions for multiple membranes, 2. Classical solution of a torsion gravity which is interacting and has local gauge and super from large N matrix model conformal symmetry until their proposal. Crucial It is well known that 2-dimensional quantum point of their proposal is introducing new gravity can be described by large N matrix model mathematical structure: Lie 3-algebra which is a through its critical phenomena. There is a similar generalization of Lie algebra. attempt to reformulate superstring theory We can consider several test whether this including quantum gravity by large N Yang-Mills proposal correctly gives the dynamics of multiple (YM) type matrix model. This matrix model is membranes in eleven dimension or not. I much more complicated than so-called “old examined the BL model in this view point with matrix model” which describes 2-dimensional Dr. Takayuki Hirayama of NCTS [1]. Our strategy gravity, because there are many numbers of was to calculate 1-loop potential between two matrices coupled each other. Therefore how to membranes with relative motion. If distance describe gravity in the large N YM matrix model between two membranes are large and relative was long standing problem. Recently it is found velocity is small, the one loop potential can be that large N matrix formally can describe curved interpreted as the Newton potential. The exponent space covariant derivative, and using this of the Newton potential tells us about dimension prescription one can obtain Einstein equation with of transverse space. Different study suggested that infinitely many higher spin fields from YM matrix BL theory would describe membranes in equation of motion. Except for the infinitely many

Research Activities of Individuals -›› 220 fields there are degrees of freedom which describe torsion. This is because torsion free condition, usually imposed in Einstein gravity, is not included in YM matrix model. Now I and Dr. Hiroshi Isono of NTU study the classical gravity equation with torsion originated from YM matrix model [3]. We are investigating on how this torsion changes large/short distance behavior of solutions of Einstein equation in vacuum.

References [1] “Membrane scattering from Bagger-Lambert theory”, Takayuki Hirayama, Dan Tomino, JHEP08(2009)071, arXiv:0812.1866. [2] “Super symmetric reduced models with a symmetry based on Filippov algebra”, Kazuyuki Furuuchi, Dan Tomino, JHEP 0905070,2009. arXiv: 0902.2041. [3] Hiroshi Isono, Dan Tomino, in preparation.

221 ‹‹- Research Activities of Individuals Research Activities on Particle Physics

Chih-Wei Wang (email: [email protected]) Postdoctoral researcher, 2008/4/1~present

n 2009, my research in NCTS has been one-to-one correspondence between the split flow focused on the detail studying of the trees and the components of well-defined microstate geometries that corresponding to some supergravity solutions. We have been studied supersymmertry black holes. The concept of more details of the supergravity solutions and try microstate geometries is based on Mathur's to understand that how this correspondence can be fuzzball proposal [1]. Roughly speaking, the true and how this correspondence explicitly work. proposal state that a classical black hole should be The initial result seems to suggest that one can thought of as some ensemble of many horizon- divide the components of the solution space of the free fuzzball states. In stronger version of the bubble equations into three subsets. One of them proposal, the majority of fuzzball states can be contains CTC's and should be regarded as realized as the solutions of supergravity. These unphysical (let's called it the bad subset). The solutions are natually can be considered as remaining two are corresponding to the split flow microstate geometries of a black hole. In 2005, a trees and the scaling solutions. While there are the family of horizon-free solutions of supergravity conjecture to ensure that the subset corresponding was discovered [2,3]. These solutions, the to the split flow trees is free of CTC's, so far there so-called bubbled geometries, are potential is no systematic way to distinguish the scaling and candidates of microstate geometries and was bad subset. However, by clarifying the relation studied in the following development [4,5,6]. In between the solutions belong to the split flow tree these papers, several examples are identified as subset and the split flow trees in the modulus microstate geometries of big black hole. However, space [9], at least one can identify a particular generally, bubbled geometries have serious subset of the solutions which is well-behaved if pathology called CTC's (closed-time-like curves). one believe the conjecture. Or one can also use To avoid the appearance of CTC's and therefore this relation to check the conjecture. the violation of the causality, one need to check if the solutions satisfy a series of the so-called bubble equations. So far, a systematic method to References study the solution space of bubble equations is [1] S. D. Mathur, The fuzzball proposal for black still lacking. Furthermore, the bubble equations holes: An elementary review, [arXiv:hep- are only the necessary conditions but not th/0502050]. sufficient. The sufficient conditions are non-local [2] I. Bena and N. P. Warner, Bubbling supertubes and require one to check every points in space. and foaming black holes, [arXiv:hep- These difficulties impede a more general search/ th/0505166]. analysis of these microstate geometries. [3]  P. Berglund, E.~G. Gimon and T. S. Levi, On the other hand, in 2007, F. Denef and G. W. Supergravity microstates for BPS black holes Moore introduce the concept of the split flow trees and black rings, [arXiv:hep-th/0505167]. [7] which they use to investigate OSV conjecture [4] I. Bena, C. W. Wang and N. P. Warner, The [8]. The phenomena of the split flows was found foaming three-charge black hole, [arXiv:hep- in the splitting behavior of the attractor flow in th/0604110]. modulus space when one study the system with multiple centers of black holes. Furthermore, they [5] I. Bena, C. W. Wang and N. P. Warner, propose the split flow conjecture that state there is Mergers and Typical Black Hole Microstates, [arXiv:hep-th/0608217].

Research Activities of Individuals -›› 222 [6] I. Bena, C. W. Wang and N. P. Warner, Plumbing the Abyss: Black Ring Microstates, [arXiv:0706.3786 [hep-th]]. [7] F. Denef and G. W. Moore, "Split states, entropy enigmas, holes and halos," [arXiv:hep-th/0702146]. [8] H. Ooguri, A. Strominger and C. Vafa, "Black hole attractors and the topological string," [arXiv:hep-th/0405146]. [9] C. W. Wang, in preparation.Phys. Lett. B.

223 ‹‹- Research Activities of Individuals Research Activities on String Theory

Yi Yang (Department of Electrophysics, National Chiao Tung University; email: [email protected]) Center scientist, 2008/8/1~1009/7/31

uring the year 2008/8/1~1009/7/31, I conformal theory (CFT) on the boundary of AdS have been working mainly on the two space-time. Compatifying a space dimension on a projects. One of them is to study the relationship circle to break all supersymmetries, and adding between the high energy behavior of string flavor D-branes, the boundary field theory is scattering amplitudes and the hidden symmetry in conjectured to dual to QCD. We proposed a string theory. The other is to study the low energy model, Dp-Dq system, to study the low energy QCD by using the AdS/CFT duality. phenomenology of QCD. We investigate light For the first topic, we continue our previous scalar mesons and glueballs in Dp-Dq hard-wall studies. During the last a couple of years, most of models, including D3-Dq, D4-Dq, and D6-Dq our studies were focus on the scattering systems. It is found that only in the D4-D6 and amplitudes in the high energy limit with a fixed D4-D8 hard wall models, the predicted mass of scattered angle. We call it Gross regime. In this the scalar meson f_0, scalar glueball are consistent regime, we found that the string scattering with their experimental or lattice results. This amplitudes in the same mass level are linear indicates that D4-D6 and D4-D8 hard wall models related each other. In addition, we are able to are favorite candidates of the realistic holographic compute all the ratios between the string QCD model [3]. scattering amplitudes for arbitrary fixed mass During the last year, I have attended the annual level by using the saddle-point approximation. conference of Strings2009 in Roma, Italy. I have These linear relations reveal that there is a hidden also visited Institute of High Energy Physics symmetry in the string theory. We believe that it is (IHEP). I would like to thank CTS to support me this hidden symmetry that guarantees the high attending the international activities. energy behavior of the string scattering amplitudes is exponential fall-off in Gross regime. The exponential fall-off behavior makes string theory a References UV finite theory and it provides a way to quantize gravity. To understand this hidden symmetry, we [1] S.L. Ko, J.C. Leee, Y.Y., Kummer function started to study the string scattering amplitudes in and High Energy String Scatterings, arXiv: the high energy limit with a small angle, i.e. 0811.4502. Regge regime, during the last year. We found that [2] S.L. Ko, J.C. Lee, Y.Y., Patterns of high there are many more general string states in the energy massive string scatterings in the Regge Regge regime are calculatable than those in the Gross regime. Furthermore, the string scattering regime, arXiv: 0812.4190. amplitudes are able to be obtained analytically in [3] C. Wang, S. He, M. Huang, Q.S. Yan and Y.Y., the Regge regime instead of using the saddle-point Scalar Mesons and glueballs in Dp-Dq hard- approximation. We found under some certain wall models, arXiv: 0902.0864. limits, the results obtained in the Regge regime reduces to the linear relations obtained in the Gross regime. This shed a light to understand the hidden symmetry in string theory beyond the linear relations [1,2]. The second topic I have studied during the last year is the so called AdS/QCD duality. This is a realistic version of the original AdS/CFT duality in string theory. In AdS/CFT duality, the type IIB string theory in an Anti-de-Sitter (AdS) space- time is conjectured to dual to an N=4 supersymmetry Yang-Mills field theory, which is a

Research Activities of Individuals -›› 224 Introducing New Members

Dr. Chun-Chung Chen

Assistant research scholar (Ph.D., University of Washington, USA) email: [email protected]

y research field consists of statistical and For the large number of neurons and synapses computational studies of non-equilibrium in an entire brain coupling with the daunting critical phenomena, self-organized criticality, disparity between the time scales of neural reversible polymer systems, and, currently, plastic activities (in milliseconds) and synaptic plasticity neural networks. (in days), we can not hope to reproduce or represent the brain dynamics through computer Advances in neurobiology has bettered our modeling of neural and synaptic dynamics under understanding of the fundamental working of the state of current technology. However, there are nervous systems, starting from the dynamic cultured networks consisting of hundreds of principle of neuronal electro-physiology of neurons that can still exhibit interesting dynamics. membrane potential, biochemistry of various The studies of these networks in vitro are serving chemicals involved in synaptic transmission, and as an important steppingstone towards the recently, to synaptic plasticity driven by neural understanding of more complicated networks. activities such as spike-timing. With these And, the dynamics of these cultured network are fundamental building blocks gradually in place, on a scale very much accessible to neural network here come the questions of what implications modeling such as that I am currently engaged in. these microscopic understandings of the neural The success of such modeling will not only help systems have on the macroscopic scale such as the to elucidate the observed behaviors of these dynamics of central nervous system or even cultured networks, such as, synchronization, animal behavior. My current research interest is in bursting, reverberation, etc. as well as their onset resolving such a relationship through the means of and maturation, but will also help to uncover computer simulations and statistical physics that possible missing pieces in the fundamental have been proven fruitful in the studies of working of neural and synaptic dynamics. condensed matter systems, which have faced similar challenges in bridging the microscopic understanding of matters with macroscopic phenomena.

225 ‹‹- Introducing New Members Dr. Pei-Jen Fareh Lin

Postdoctoral researcher (Ph.D., National Chiao Tung University, Taiwan) email: [email protected], [email protected]

uring Winter of 2008, I started my The relation between response and input signal is postdoctoral position at the physical division of not a simple linear relation. In addition, I have NCTS after graduating under the supervision of made a necessary improvement of TDGL to Prof. B. Rosenstein at NCTU. accommodate fast response, since the usual phase transition theory is based on equilibrium I have a broad interest in Physics in general. conditions and its eventual time-dependent What fascinates me the most is the deep versions apply only to asymptotically slow consequences of statistical physics. In particular, I changes. Making use of these modifications to the am interested in the behaviour of macroscopic standard theory, I studied far infrared magneto- collective modes, solitons, predominantly the transmission for frequencies near but below the physical properties of a strongly correlated optical gap. I compare my result with recent system, rather than the microscopic nature of a experimental data on NbN from 2009. In material. Currently, I am focusing on the measurement made using light of short pulses, the dynamical properties of systems with effects of higher electric fields become comparatively fast response. measurable. I plan to extend my study in the Quantised magnetic flux in type-II vortex solid state to more interesting states visible superconductors is referred to as vortex matter. in high-temperature superconductors such as Since the interaction within this vortex matter liquid, glass and Bragg glass. depends on parameters which may be controlled Furthermore, I plan to initiate a study of other by external magnetic field and temperature, vortex systems with second-order phase transitions; such matter provides an excellent opportunity for study. systems rapidly change their physical properties Thermal excitation, pinning (from a without release of latent heat or dramatic changes background), and internal coupling are some of of their volumes. In fact, many of these systems the phenomena contributing to the intricate H-T are interesting from an applied-technology point phase diagram of vortex matter. Probing such a of view in practical devices. Perhaps the most system with an external oscillating force, the familiar device using some of this technology is response can be observed. In performing such the LCD screen, based on phase transitions in measurements, the choice of frequency of the liquid crystals. oscillating field determines the time scale under study. I have obtained a response function for a system with driving force based on the Time- Dependent Ginzburg-Landau model analytically.

Introducing New Members -›› 226 Dr. Eibun Senaha

Postdoctoral researcher (Ph.D., the Graduate University for Advanced Studies , Japan) email: [email protected]

received my Ph.D in physics at the scales such as the Grand Unified Theory or the Graduate University for Advanced seesaw model. The other is the so-called the Studies in Japan in 2005. After being a electroweak baryogenesis, which exclusively postdoctral fellow at National Central University relies on physics at scales that we can reach by the in Taiwan for three years, I moved on to NCTS in collider experiments. At the LHC/ILC era, the August, 2009 as a postoctral fellow. latter scenario can be completely tested, and thus the theoretical calculations are more urgent. So My principal research interest is far, I have been working on electroweak phenomenology of particle physics, especially, baryogenesis in the minimal supersymmetric Higgs physics, CP violation and their standard model and beyond. The reduction of the cosmological implication. Currently, I am tackling errors in the calculation of the electroweak phase an issue of the Baryon Asymmetry of the Universe transition and sphaleron decoupling condition (BAU). Unfortunately, the standard model (SM), using the two-loop effective potential are in which is a most successful theory in particle progress. The technique which we are developing physics, failed to explain the BAU due to the can be applied to any other beyond the SM. smallness of CP violation in the Cabibbo- Kobayashi-Maskawa matrix and the lack of strong first order phase transition. In general, two approaches can exist to explain the BAU. One scenario is based on physics at the high-energy

227 ‹‹- Introducing New Members