Motion-Enhanced Quantum Entanglement in the Dynamics of Excitation Transfer *

ISSN: 0256-307X 中国物理快报 Chinese Physics Letters

Volume 32 Number 8 August 2015 A Series Journal of the Chinese Physical Society Distributed by IOP Publishing Online: http://iopscience.iop.org/0256-307X http://cpl.iphy.ac.cn

C HINESE P HYSICAL S OCIET Y

CHIN. PHYS. LETT. Vol. 32, No. 8 (2015) 088701 Motion-Enhanced Quantum Entanglement in the Dynamics of Excitation Transfer *

SONG Wei(宋伟)1**, HUANG Yi-Sheng(黄怿晟)2, YANG Ming(杨名)2, CAO Zhuo-Liang(曹卓良)1 1Institute for Quantum Control and Quantum Information, and School of Electronic and Information Engineering, Hefei Normal University, Hefei 230601 2School of Physics and Material Science, Anhui University, Hefei 230601

(Received 15 March 2015) We investigate the dynamics of entanglement in the excitation transfer through a model consisting of three interacting molecules coupled to environments. It is shown that the entanglement can be further enhanced if the distance between the molecules is oscillating. Our results demonstrate that the motional effect plays a constructive role on quantum entanglement in the dynamics of excitation transfer. This mechanism might provide a useful guideline for designing artificial systems to battle against decoherence.

PACS: 87.15.A−, 87.15.hj, 03.67.−a DOI: 10.1088/0256-307X/32/8/088701

Usually quantum entanglement is regarded as a of quantum coherence in light harvesting efficiency. fragile resource and very sensitive to noise. Thus we In particular, Sarovar et al.[25] present numerical evi- need rigorous laboratory conditions to manufacture dences for the existence of entanglement in the FMO and maintain entanglement. It is believed that en- complex for relatively long times. The influence of tanglement cannot exist outside the laboratories, not Markovian, as well as non-Markovian noise on the dy- to mention biological systems, which are wet and hot, namics of entanglement in FMO complex have also and with extremely high levels of noise.[1] However, been analyzed by Caruso et al.[27] several recent studies have shown that entanglement The third aspect includes the investigation of en- might exist in non-equilibrium systems and survive tanglement in larger light harvesting complexes. Light for relatively long time scales at physiological temper- harvesting complex II (LHCII) is the most abundant atures in biological systems. To date, these studies photosynthetic antenna complex in plants containing can be divided into three aspects: the first aspect over 50% of the world’s chlorophyll molecules.[29,30] is focused on quantum entanglement in model sys- It is shown that LHCII also exhibits long-lived elec- tems. The first study was made by Thorwart et al.[2] tronic coherence. Ishizaki et al.[28] have investigated who demonstrate that enhanced quantum entangle- quantum entanglement in LHCII across different bi- ment in the non-Markovian dynamics of biomolecular partitions of the chlorophyll pigments. excitons. It was shown in Ref. [3] that dynamic entan- However, in previous investigations, the motional glement can be continuously generated in noisy non- effect of the molecules in the dynamics of excita- equilibrium systems. Subsequently, this phenomenon tion transfer is omitted. It is suggested that con- has been generalized to the spin gas model and non- formational motion is an important feature of molec- Markovian models.[4] Galve et al.[5] also predict that ular processes, such as protein folding or excitation nanomechanical oscillators can be entangled at much transfer in light harvesting complex. These lead higher temperatures than those previously thought to effectively time-dependent interactions, with their possible. strengths modulated by the motion of the molecular. The second aspect is quantum entanglement in In analogy to the static case, the effect of the motion Fenna–Matthews–Olson (FMO) complex of green sul- on the entanglement dynamics of excitation transfer is fur bacterium. The FMO complex is a water solu- far from being understood. Here we tackle this prob- ble complex and acts as a molecular wire to transfer lem by considering a model consisting of three inter- the excitation energy from the light harvesting an- acting molecules driven through the oscillating mo- tenna to the reaction center. Many theoretical stud- tion. Our studies demonstrate that for a wide range ies in light harvesting structures are focused on the of parameters, the average entanglement can be en- FMO due to its well characterized pigment-protein hanced if the motional effect is taken into account. In structure. Recent experiments by Engel et al.[6] and our discussion, we assume that the conformational mo- Panitchayangkoon et al.[7] have shown that the elec- tion of the molecular structure can be described classi- tronic coherence between two excitonic levels at both cally. This semi-quantal approximation holds if the in- cryogenic (77 K) and ambient (300 K) temperatures. volved molecules are too large to show their quantum These experimental studies have generated numerous behavior.[4] Motion of the individual molecules leads theoretical interests[8−24] in understanding the role to a change in dipole moments and thus also induces

*Supported by the National Natural Science Foundation of China under Grant Nos 11374085, 61073048 and 11274010, the Specialized Research Fund for the Doctoral Program of Higher Education under Grant No 20113401110002, the 211 Project of Anhui University, the Anhui Provincial Natural Science Foundation under Grant No 1408085MA20, the Personnel Department of Anhui Province, and the 136 Foundation of Hefei Normal University under Grant No 2014136KJB04. **Corresponding author. Email: [email protected] © 2015 Chinese Physical Society and IOP Publishing Ltd 088701-1 CHIN. PHYS. LETT. Vol. 32, No. 8 (2015) 088701 a time-dependence of the coupling. This mechanism the form will be dominant whenever the molecules are tightly 푁 embedded in a protein scaffold such as in the FMO ∑︁ + − − + complex. For simplicity, we only consider the modu- 퐿diss(휌) = Γ푛[−{휎푛 휎푛 , 휌} + 2휎푛 휌휎푛 ], (3) lation of coupling strength due to the change in dis- 푛=1 tance. According to Ref. [4], we choose the motion of + − where 휎푛 = |푛⟩⟨0| and 휎푛 = |0⟩⟨푛| are, respectively, the molecules change their distance periodically, which the raising and lowering operators for site 푛, and |0⟩ holds for small amplitudes in the harmonic regime. refers to the zero exciton state of the system. The Furthermore, we suppose that the molecules are dis- symbol {퐴, 퐵} is an anticommutator, and Γ푛 denotes tant enough from each other such that we only con- the dissipation rate of the 푛th molecule. sider the nearest neighbor interactions. In natural conditions, it is reasonable to consider at most one 1.0 excitation during the excitation transfer process.[25] (a) 0.8 Under these conditions, the Hamiltonian of the chain of interacting molecules in the single-excitation 0.6 manifold can be written as 0.4

Concurrence 0.2 푁 푁−1 ∑︁ ∑︁ 0.0 퐻 = 휀푛|푛⟩⟨푛| + 퐽푛(|푛⟩⟨푛 + 1| + |푛 + 1⟩⟨푛|), 1.0 푛=1 푛=1 (1) 0.8 where |푛⟩ represents the state with the excitation at 0.6 the 푛th site having energy 휀푛 and all other states are 0.4 in their electronic ground state, and 퐽 is the cou- 푛 Concurrence 0.2 pling strength between the 푛th and the (푛 + 1)th molecule. Motion of the molecules will induce a time- 0.0 dependent coupling strength and deformation of the 1.0 molecules will also lead to the change of dipolar cou- 0.8 pling. For simplicity, we suppose that the coupling 0.6 strength only changes with the relative distance between the molecules. Suppose that the distance be- 0.4 Concurrence tween the molecules 푛 and 푛 + 1 is 푑푛(푡) = 푑0 − 0.2 [푢 (푡) − 푢 (푡)] = 푑 [1 − 2푎 sin(휔푡 + 휑 )], where 0.0 푛 푛+1 0 푛 푛 0 1 2 3 4 5 6 7 8 푢푛(푡) denotes the position of the 푛th molecule, 푑0 t is the equilibrium distance between two neighboring Fig. 1. (Color online) Time evolutions of the entangle- molecules, and 푎푛 is the individual sites’ relative am- ment of molecules 1 and 2, in the motional case (red line), plitude of oscillation. Correspondingly, the dipole- and in the static case (blue line): (a) 휔 = 1, 푎1 = 1/4, (b) dipole coupling strength between two molecules is 휔 = 2, 푎1 = 1/4, and (c) 휔 = 5, 푎1 = 1/3. [3,4] given by To model the dynamics of the excitation transfer along a chain of molecules, we introduce an additional site, the sink that resembles the reaction center in pho- 퐽˜ 퐽 0 0 tosynthesis. It denotes an irreversible decay of exci- 퐽푛(푡) = 3 = 3 , (2) [푑푛(푡)] [1 − 2푎푛 sin(휔푡 + 휑푛)] tations from the site 푁 to the last 푁 + 1 site. The absorption of the energy from the site 푁 to the sink ˜ 3 ˜ where we have defined 퐽0 = 퐽0/푑0, and 퐽0 contains (numbered 푁 + 1) is modeled by a Lindblad operator the dipole moments and physical constants. Here + − + − our discussion corresponds to a given amplitude, fre- 퐿sink(휌) = Γs[2휎푁+1휎푁 휌휎푁 휎푁+1 + − + − quency, and phase synchronized with the propagation − {휎푁 휎푁+1휎푁+1휎푁 , 휌}], (4) of the excitation. This assumption is reasonable due to the fact that the wave packet that describes the nu- where Γs is the absorption rate of the sink which de- clear motion has been observed to exhibit surprisingly scribes the irreversible decay of the excitations to the long coherence times in reaction center proteins.[26] sink. Thus the master equation of the density matrix Although this model is rather simple, several biologi- 휌 of the system is given by cal systems show a similar structure that agrees with 푑휌 the assumptions underlying our model. For example, = 푖[휌, 퐻] + 퐿diss(휌) + 퐿sink(휌). (5) a type of secondary structure in proteins named 훼- 푑푡 helix or FMO complex, among which an excitation To study the role of the motional effect on en- can be exchanged due to dipole-dipole couplings be- tanglement, we only consider the simplest case of a tween the molecules. Firstly, we assume that all sites chain composed of only 푁 = 2 interacting molecules, are subjected to dissipative noise. This process can be labeled 1 and 2 plus the sink labeled 3. The ex- introduced by considering a Lindblad term 퐿diss(휌) in citon is transferred from molecules 1 to 3 through 088701-2 CHIN. PHYS. LETT. Vol. 32, No. 8 (2015) 088701 the linear chain and finally is trapped by the sink. Fig. 1(a) we can calculate that 퐶¯(퐽0) = 0.1461 > Molecules 1 and 2 are subjected to the dissipative 퐶¯(퐽max) = 0.1136, where we have chosen the time environment simultaneously. The coupling strength in the range 0 ≤ 푇 ≤ 8. Similarly, in the cases between the two sites is modulated by the oscil- of Figs. 1(b) and 1(c) we have 퐶¯(퐽0) = 0.1571 > lating motion of the molecules. In our discus- 퐶¯(퐽max) = 0.1136 and 퐶¯(퐽0) = 0.1637 > 퐶¯(퐽max) = sion, we suppose the local energies 휀1 = 휀2 = 휀. 0.1133, respectively, with numerical calculations. Ob- This simple model provides a platform to demon- viously, the average entanglement is larger than the strate the dynamics of entanglement in the exci- static case in these three cases. In Fig. 2(a) we plot tation transfer process driven through the oscillat- the average entanglement versus frequency 휔 with ing motion. Here we use Wootter’s concurrence[31] 0 ≤ 휔 ≤ 10. The red line corresponds to the time- to quantify entanglement,√ √ which√ can√ be defined as dependent coupling strength and the blue line repre- 퐶(휌) = max{0, 휆1 − 휆2 − 휆3 − 휆4}, where 휆푖 sents the static case. We can see that the average are the eigenvalues in decreasing order of the ma- entanglement oscillates rapidly around the static case * * trix 휌휌˜ = 휌휎푦 ⊗ 휎푦휌 휎푦 ⊗ 휎푦 with 휌 denoting the for small 휔. For fast motion, i.e., for larger 휔, the os- complex conjugation of 휌. We choose the parameter cillating motion plays a constructive role in contrast 휋 Γ1 = Γ2 = 0.2, Γs = 0.5, 휑 = 2 , 퐽0 = 1, where to the static case. This enhancement is valid only 휋 휑 = 2 indicates that the two molecules are closest at for a window of 휔. This effect can be understood the initial time. as follows. The oscillating of the molecule leads to a We suppose that the initial state has an excitation population redistribution, as compared with the static localized on molecule 1. By numerically solving the case. The enhancement of entanglement corresponds master Eq. (5), we plot the entanglement evolution of to a relatively larger population in molecules 1 and molecules 1 and 2 in Fig. 1 with red line. In this case, 2. This means that motion might prevent excitation the coupling strength 퐽(푡) is time-dependent and is transfer from the molecule chain to the sink for some driven through the oscillating motion of the molecules. 휔. Thus the enhancement of entanglement is accom- In Fig. 1(a) we choose the parameters 휔 = 1 and panied with the decrease of the sink population. This 1 푎1 = 4 for the motional case. For comparison, we explanation can be confirmed in Fig. 2(b), in which also consider the static case with constant 퐽, and the we plot the average evolution of sink population ver- coupling strength 퐽max = 8 when the molecules have sus 휔. Here the sink population at time 푡 is defined as the closest distance. The blue line represents the evo- 푝(푡) = Tr(|3⟩⟨3|휌(푡)), where |3⟩ denotes the sink. The lution of entanglement in the static case. In Figs. 1(b) average sink population is given by 푝¯ = 1 ∫︀ 푇 푝(푡)푑푡. 1 푇 0 and 1(c), we choose the parameters 휔 = 2, 푎1 = 4 , It can be seen from Fig. 2(b) that the entanglement is 1 퐽max = 8 and 휔 = 5, 푎1 = 3 , 퐽max = 27, respectively. enhanced when the population is decreased with fixed Figure1 shows that, in the motional case, entangle- 휔. There exists a tradeoff relation between the average ment has a larger value than the static case for a wide entanglement and the average sink population. range of time. 0.16 (a) 0.16 (b) 0.16 0.14 0.14 (a) nt 0.12 0.14 0.10 0.12 0.08 0.10 0.12 0.06 0.08 0.18 (c) 0.25 0.1 0.16 (d) 0.20 0.14 0.08 0.12 0.15 0.10 0.06 0.10 Average entanglement Average 0.08

Average entangleme Average 0.05 0.04 0.06 0 2 4 ω 6 8 10 0 2 4 ω 6 8 10 0.8 (b) Fig. 3. (Color online) The average entanglement evolu- 0.7 tions versus 휔 with different 휑: (a) 휑 = 휋/6, (b) 휑 = 휋/3, (c) 휑 = 2휋/3, and (d) 휑 = 5휋/6. 0.6 ulation

Pop 0.5 The previous discussion was limited to the ini- 휋 tial condition 휑 = 2 for the molecules in the closest 0.4 distance. To test whether our results hold for other 0 2 4 6 8 10 ω 휋 휋 2휋 5휋 phases, we set 휑 = 6 , 휑 = 3 , 휑 = 3 , and 휑 = 6 , Fig. 2. (Color online) (a) The average entanglement evo- respectively, in Fig.3. It shows that the enhance- lutions versus 휔, in the motional case (red line), and in ment of entanglement still exists for other phases. If static case (blue line). (b) The average sink population 0 ≤ 휑 ≤ 휋, the evolution of entanglement strongly evolutions versus 휔, in the motional case (green line), and modulated by the initial phases and the window of 휔 휑 = 휋/2 in static case (yellow line). The parameters are , increases with the initial phase. As seen in Fig. 3(d) 푎1 = 1/4 and 0 ≤ 푇 ≤ 8. that the entanglement is larger than the static case To further illustrate the dynamics of entanglement for almost all 휔. In Fig. 4 we also plot the evolution of with different 휔, we introduce the average entangle- average entanglement with different 푎1, the other pa- ¯ 1 ∫︀ 푇 휋 ment defined as 퐶 = 푇 0 퐶(푡)푑푡 for fixed 휔. From rameters are Γ1 = Γ2 = 0.2, Γs = 0.5, 휑 = 2 , 퐽0 = 1, 088701-3 CHIN. PHYS. LETT. Vol. 32, No. 8 (2015) 088701

휔 = 1. Here the maximal coupling strength in the ions and the two internal levels of trapped ions can 퐽0 static case is given by 퐽max = 3 . encode the two-level system. The classical oscillation (1−2푎1) can be simulated by tuning the interaction strength 0.14 and the transverse fields, which is achievable, e.g., by 0.12 changing the amplitudes of laser beams as suggested in 0.10 Ref. [3]. In a biological context, such mechanical mo- 0.08 tion can be regarded as conformational changes which 0.06 plays a vital role in many molecular processes. Here 0.04 we model these conformational changes as purely clas- 0.02 sical oscillating of the molecules. This effect suggests

Average entanglement Average 0 that biological systems might utilize this mechanics 0 0.05 0.1 0.15 0.2 0.25 0.30 0.35 0.4 a1 to protect entanglement in natural environments. Our results may have potential applications in future artifi- Fig. 4. (Color online) The average entanglement evolu- cial systems to maintain entanglement in the presence tions versus 푎1 with 휑 = 휋/2 and 휔 = 1. of environment noises.

0.195 0.2 We thank Huang Xiaoli for helpful discussions on (a) (b) 0.19 0.195 numerical simulations. 0.19 0.185 0.185 0.18 0.18 0.175 0.175 References 0.195 (c) 0.18 (d) 0.19 0.17 0.16 [1] Briegel H J and Popescu S 2008 arXiv:0806.4552[quant-ph] 0.185 0.15 [2] Thorwart M et al 2009 Chem. Phys. Lett. 478 234 0.18 [3] Cai Jianming et al 2010 Phys. Rev. E 82 021921

Average entanglement Average 0.14 0.175 0.13 [4] Guerreschi G G et al 2012 New J. Phys. 14 053043 0 2 4 6 8 10 0 2 4 6 8 10 ω ω [5] Galve F et al 2010 Phys. Rev. Lett. 105 180501 [6] Engel G S et al 2007 Nature 446 782 Fig. 5. (Color online) The average entanglement evo- [7] Panitchayangkoon G, Hayes D, Fransted K A, Caram J R, lutions versus 휔 for the initial state √1 (|1⟩ + |2⟩): (a) Harel E, Wen J, Blankenship R E and Engel G S 2010 Proc. 2 Natl. Acad. Sci. USA 107 휑 = 휋/6, (b) 휑 = 5휋/6. The parameters in (c) and 12766 New J. Phys. 10 (d) are similar to (a) and (b) except the initial state is [8] Plenio M B and Huelga S F 2008 113019 [9] Nalbach P, Braun D and Thorwart M 2011 Phys. Rev. E √︁ 1 √︁ 2 3 |1⟩ + 3 |2⟩. 84 041926 [10] Ai B Q and Zhu S L 2012 Phys. Rev. E 86 061917 Finally, we investigate whether our results also [11] Castro A Olaya, Lee C F, Olsen F F and Johnson N F 2008 hold for other initial states. Firstly, the initial state is Phys. Rev. B 78 085115 set in the maximal superposition state √1 (|1⟩ + |2⟩), [12] Kassal I, Zhou J Y and Keshari S R 2013 J. Phys. Chem. 2 Lett. 4 휋 1 362 the other parameters are 휑 = 2 , 푎1 = 4 , 0 ≤ 푇 ≤ 8. [13] Yang S, Xu D Z, Song Z and Sun C P 2010 J. Chem. Phys. Figures5(a) and 5(b) show the evolutions of entangle- 132 234501 ment versus 휔 with 휑 = 휋 , and 휑 = 5휋 , respectively. [14] Chin A W, Datta A, Caruso F, Huelga S F and Plenio M 6 6 B 2010 New J. Phys. 12 065002 Obviously, the average entanglement is always larger [15] Liang X T 2010 Phys. Rev. E 82 051918 than the static case for this initial state. The parame- [16] Ishizakia A and Fleming G R 2009 Proc. Natl. Acad. Sci. ters in Figs. 5(c) and 5(d) are similar to Figs. 5(a) and USA 106 17255 √︁ √︁ [17] Ghosh P K, Smirnov A Y and Nori F 2011 J. Chem. Phys. 1 2 134 5(b) except that the initial state is 3 |1⟩ + 3 |2⟩. 244103 Figure 5 shows that, when the initial state is a super- [18] Tan Q S and Kuang L M 2012 Commun. Theor. Phys. 58 359 position state, motion helps to enhance entanglement [19] Rey M, Chin A W, Huelga S F and Plenio M B 2013 J. better than the initial state |1⟩. Phys. Chem. Lett. 4 903 In the above discussions, we have modeled the [20] Asadian A, Tiersch M, Guerreschi G G, Cai Jianming, Popescu S and Briegel H J 2010 New J. Phys. 12 075019 environment as dissipative noise. To test how [21] Li H R, Zhang P, Liu Y J, Li F L and Zhu S Y 2013 Phys. the dephasing process affects the dynamics of en- Rev. A 87 053831 tanglement, we can add an additional dephasing [22] Qin M, Shen H Z, Zhao X L and Yi X X 2014 Phys. Rev. E 90 042140 term in Eq. (5), which is given by 퐿deph(휌) = 푁 [23] Zhang Y P, Li H R, Fang A P, Chen H and Li F L 2013 ∑︀ 훾 (2휎+휎−휌휎+휎− − {휎+휎−, 휌}). Numerical sim- Chin. Phys. B 22 057104 푛 푛 푛 푛 푛 푛 푛 [24] Wang X L, Li H R, Zhang P, Li F L 2013 Chin. Phys. B 22 푛=1 ulation shows that the dephasing noise cannot alter 117102 [25] Sarovar M, Ishizaki A, Fleming G R and Whaley K B 2010 our results and dephasing only affects the amplitude Nat. Phys. 6 462 of entanglement. [26] Vos M H, Rappaport F, Lambry J C, Breton J and Martin In summary, we have investigated the dynamics J L 1993 Nature 363 320 of entanglement in the excitation transfer through [27] Caruso F, Chin A W, Datta A, Huelga S F and Plenio M B 2010 Phys. Rev. A 81 062346 a model consisting of three interacting molecules [28] Ishizaki A and Fleming G R 2010 New J. Phys. 12 055004 coupled to environments. The results presented [29] Amerongen H van, Valkunas L, Grondelle R van 2000 Pho- here demonstrate that quantum entanglement can tosynthetic Excitons (Singapore: World Scientific) [30] Blankenship R E 2002 Molecular Mechanisms of Photosyn- be enhanced through the mechanical motion of the thesis (New York: John Wiley & Sons) molecules. Our model can be simulated with trapped [31] Wootters W K 1998 Phys. Rev. Lett. 80 2245 088701-4 Chinese Physics Letters Volume 32 Number 8 August 2015

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ATOMIC AND MOLECULAR PHYSICS 083101 Static Dipole Polarizabilities for Low-Lying Rovibrational States of HD+ TIAN Quan-Long, TANG Li-Yan, YAN Zong-Chao, SHI Ting-Yun 083102 Stereodynamics Study of Li+HF→LiF+H Reactions on X2A0 Potential Energy Surface at Collision Energies below 5.00 kcal/mol LI Hong-Zheng, LIU Xin-Guo, TAN Rui-Shan, HU Mei 083201 Experimental Scheme of 633 nm and 1359 nm Good-Bad Cavity Dual-Wavelength Active Optical Frequency Standard XU Zhi-Chao, PAN Duo, ZHUANG Wei, CHEN Jing-Biao 083401 Laser Polarization Orientations in (e, 2e) Reactions in Atoms Ajana I., Makhoute A., Khalil D. 083601 Triplet Exciton Transition Induced Highly Efficient Fluorescent Channel in Organic Electroluminescence CHEN Ren-Ai, SUN Xin 083701 Preparation of Ultracold Li+ Ions by Sympathetic Cooling in a Linear Paul Trap CHEN Ting, DU Li-Jun, SONG Hong-Fang, LIU Pei-Liang, HUANG Yao, TONG Xin, GUAN Hua, GAO Ke-Lin FUNDAMENTAL AREAS OF PHENOMENOLOGY(INCLUDING APPLICATIONS) 084201 Tunable, High-Order Harmonically Mode-Locked All-Normal-Dispersion Ytterbium Fiber Laser LV Zhi-Guo, TENG Hao, WANG Li-Na, WANG Rui, WEI Zhi-Yi 084202 Quaternion Approach to Solve Coupled Nonlinear SchrödingerEquation and Crosstalk of Quarter-Phase-Shift-Key Signals in Polarization Multiplexing Systems LIU Lan-Lan, WU Chong-Qing, SHANG Chao, WANG Jian, GAO Kai-Qiang 084203 Optimization of 1.3-µm InGaAsP/InP Electro-Absorption Modulator WANG Hui-Tao, ZHOU Dai-Bing, ZHANG Rui-Kang, LU Dan, ZHAO Ling-Juan, ZHU Hong-Liang, WANG Wei, JI Chen 084204 A Mid-IR Optical Parametric Oscillator Pumped by an Actively Q-Switched Ho:YAG Ceramic Laser YUAN Jin-He, DUAN Xiao-Ming, YAO Bao-Quan, LI Jiang, SHEN Ying-Jie, CUI Zheng, DAI Tong-Yu, PAN Yu-Bai 084205 Experimental Study on a Passively Q-Switched Ho:YLF Laser with Polycrystalline Cr2+:ZnS as a Saturable Absorber CUI Zheng, YAO Bao-Quan, DUAN Xiao-Ming, LI Jiang, BAI Shuang, LI Xiao-Lei, ZHANG Ye, YUAN Jin-He, DAI Tong-Yu, JU You-Lun, LI Chao-Yu, PAN Yu-Bai 084301 High-Frequency Guided Wave Scattering by a Partly Through-Thickness Hole Based on 3D Theory ZHANG Hai-Yan, XU Jian, MA Shi-Wei 084601 Numerical Simulation of Two Different Flexible Bodies Immersed in Moving Flow WANG Si-Ying, HUANG Ming-Hai, YIN Xie-Zhen

PHYSICS OF GASES, PLASMAS, AND ELECTRIC DISCHARGES 085201 Diagnostics of Metal Plasma in Radio Frequency Glow Discharge during Electron Beam Evaporation YU Yong-Hao, WANG Lang-Ping, WANG Xiao-Feng, JIANG Wei, CHEN Qiong 085202 The Impact of Beam Deposition on Bootstrap Current of Fast Ion Produced by Neutral Beam Tangential Injection HUANG Qian-Hong, GONG Xue-Yu, LU Xing-Qiang, YU Jun, CAO Jin-Jia 085203 Positron-Acoustic Shock Waves in a Degenerate Multi-Component Plasma Shah M. G., Hossen M. R., Sultana S., Mamun A. A.

CONDENSED MATTER: STRUCTURE, MECHANICAL AND THERMAL PROPERTIES 086201 Properties of Liquid Nickel along Melting Lines under High Pressure CAO Qi-Long, WANG Pan-Pan, HUANG Duo-Hui, YANG Jun-Sheng, WAN Ming-Jie, WANG Fan-Hou 086801 Thermal Conductance of Cu and Carbon Nanotube Interface Enhanced by a Graphene Layer HUANG Zheng-Xing, WANG Li-Ying, BAI Su-Yuan, TANG Zhen-An 086802 Surface Acoustic Wave Humidity Sensors Based on (1120)¯ ZnO Piezoelectric Films Sputtered on R-Sapphire Substrates WANG Yan, ZHANG Shu-Yi, FAN Li, SHUI Xiu-Ji, YANG Yue-Tao

CONDENSED MATTER: ELECTRONIC STRUCTURE, ELECTRICAL, MAGNETIC, AND OPTICAL PROPERTIES

087101 Anisotropic Transport and Magnetic Properties of Charge-Density-Wave Materials RSeTe2 (R = La, Ce, Pr, Nd) WANG Pei-Pei, LONG Yu-Jia, ZHAO Ling-Xiao, CHEN Dong, XUE Mian-Qi, CHEN Gen-Fu 087102 Ti/Al Based Ohmic Contact to As-Grown N-Polar GaN FENG Zhi-Hong, WANG Xian-Bin, WANG Li, LV Yuan-Jie, FANG Yu-Long, DUN Shao-Bo, ZHAO Zheng-Ping 087103 Eﬀects of N on Electronic and Mechanical Properties of H-Type SiC LIU Yun-Fang, CHENG Lai-Fei, ZENG Qing-Feng, ZHANG Li-Tong 087201 Thermal Analysis of Organic Light Emitting Diodes Based on Basic Heat Transfer Theory ZHANG Wen-Wen, WU Zhao-Xin, LIU Ying-Wen, DONG Jun, YAN Xue-Wen, HOU Xun

087401 Growth of High-Quality Superconducting FeSe0.5Te0.5 Thin Films Suitable for Angle-Resolved Photoemission Spectroscopy Measurements via Pulsed Laser Deposition KONG Wan-Dong, LIU Zhi-Guo, WU Shang-Fei, WANG Gang, QIAN Tian, YIN Jia-Xin, RICHARD Pierre, YAN Lei, DING Hong 0 087501 Structure and Magnetic Properties of the γ -Fe4N Films on Cu Underlayers JIANG Feng-Xian, ZHAO Ye, ZHOU Guo-Wei, ZHANG Jun, FAN Jiu-Ping, XU Xiao-Hong 087502 RC-Circuit-Like Dynamic Characteristic of the Magnetic Domain Wall in Flat Ferromagnetic Nanowires CHEN Cheng, PIAO Hong-Guang, SHIM Je-Ho, PAN Li-Qing, KIM Dong-Hyun

087503 Ferroelectricity in the Ferrimagnetic Phase of Fe1−xMnxV2O4 ZHAO Ke-Han, WANG Yu-Hang, SHI Xiao-Lan, LIU Na, ZHANG Liu-Wan 087504 Large Tunability of Physical Properties of Manganite Thin Films by Epitaxial Strain WEI Wen-Gang, WANG Hui, ZHANG Kai, LIU Hao, KOU Yun-Fang, CHEN Jin-Jie, DU Kai, ZHU Yin-Yan, HOU Deng-Lu, WU Ru-Qian, YIN Li-Feng, SHEN Jian

CROSS-DISCIPLINARY PHYSICS AND RELATED AREAS OF SCIENCE AND TECHNOLOGY 088101 Defect Reduction in GaAs/Si Films with the a-Si Buﬀer Layer Grown by Metalorganic Chemical Vapor Deposition WANG Jun, HU Hai-Yang, HE Yun-Rui, DENG Can, WANG Qi, DUAN Xiao-Feng, HUANG Yong-Qing, REN Xiao-Min 088102 Preparation of Ta-Doped TiO2 Using Ta2O5 as the Doping Source XU Cheng, LIN Di, NIU Ji-Nan, QIANG Ying-Huai, LI Da-Wei, TAO Chun-Xian 088103 Growth of a-Plane GaN Films on r-Plane Sapphire by Combining Metal Organic Vapor Phase Epitaxy with the Hydride Vapor Phase Epitaxy JIANG Teng, XU Sheng-Rui, ZHANG Jin-Cheng, LIN Zhi-Yu, JIANG Ren-Yuan, HAO Yue 088104 Nano-Crystalline Diamond Films Grown by Radio-Frequency Inductively Coupled Plasma Jet Enhanced Chemical Vapor Deposition SHI Yan-Chao, LI Jia-Jun, LIU Hao, ZUO Yong-Gang, BAI Yang, SUN Zhan-Feng, MA Dian-Li, CHEN Guang-Chao 088301 Eﬀect of Abrasive Concentration on Chemical Mechanical Polishing of Sapphire YAN Wei-Xia, ZHANG Ze-Fang, GUO Xiao-Hui, LIU Wei-Li, SONG Zhi-Tang

088401 InxGa1−xN/GaN Multiple Quantum Well Solar Cells with Conversion Eﬃciency of 3.77% LIU Shi-Ming, XIAO Hong-Ling, WANG Quan, YAN Jun-Da, ZHAN Xiang-Mi, GONG Jia-Min, WANG Xiao-Liang, WANG Zhan-Guo 088501 Impact of Band-Engineering to Performance of High-k Multilayer Based Charge Trapping Memory LIU Li-Fang, PAN Li-Yang, ZHANG Zhi-Gang, XU Jun 088502 Anomalous Channel Length Dependence of Hot-Carrier-Induced Saturation Drain Current Degradation in n-Type MOSFETs ZHANG Chun-Wei, LIU Si-Yang, SUN Wei-Feng, ZHOU Lei-Lei, ZHANG Yi, SU Wei, ZHANG Ai-Jun, LIU Yu-Wei, HU Jiu-Li, HE Xiao-Wei 088503 Discrimination Voltage and Overdrive Bias Dependent Performance Evaluation of Passively Quenched SiC Single-Photon-Counting Avalanche Photodiodes LIU Fei, YANG Sen, ZHOU Dong, LU Hai, ZHANG Rong, ZHENG You-Dou

088504 High Responsivity Organic Ultraviolet Photodetector Based on NPB Donor and C60 Acceptor WANG Yong-Fan, QU Feng-Dong, ZHOU Jing-Ran, GUO Wen-Bin, DONG Wei, LIU Cai-Xia, RUAN Sheng-Ping 088505 Laser-Induced Single Event Transients in Local Oxidation of Silicon and Deep Trench Isolation Silicon-Germanium Heterojunction Bipolar Transistors LI Pei, GUO Hong-Xia, GUO Qi, ZHANG Jin-Xin, WEI Ying, 088506 Temperature-Dependent Drain Current Characteristics and Low Frequency Noises in Indium Zinc Oxide Thin Film Transistors LIU Yuan, WU Wei-Jing, QIANG Lei, WANG Lei, EN Yun-Fei, LI Bin 088701 Motion-Enhanced Quantum Entanglement in the Dynamics of Excitation Transfer SONG Wei, HUANG Yi-Sheng, YANG Ming, CAO Zhuo-Liang 088801 Eﬀect of Valence Band Tail Width on the Open Circuit Voltage of P3HT:PCBM Bulk Heterojunction Solar Cell: AMPS-1D Simulation Study Bushra Mohamed Omer 088901 Exact Solution for Clustering Coeﬃcient of Random Apollonian Networks FANG Pin-Jie, ZHANG Duan-Ming, HE Min-Hua, JIANG Xiao-Qin