Institute of Advanced Studies Editor-In-Chief: Prof Phua Kok Khoo,

Director, Institute of Advanced Studies, NTU, Singapore

ISSUE 18 • January 2016

2nd Pan Asia Liberal Arts Education Conference with 8 university presidents and other experts in Liberal Arts Education!

▪ Celebrating 60 Years of Yang-Mills Gauge Field Theories ▪ 2nd Singapore Sustainability Symposium ▪ CN Yang Scholars’ Informal Dialogue with Nobel Laureate Prof Chen-Ning Yang IAS NEWSLETTER - ISSUE 18 CONTENTS

Editor-in-Chief Phua Kok Khoo FEATURES

Members 03 | The 2nd Pan Asia Liberal Arts Education Conference Kwek Leong Chuan Low Hwee Boon Xiong Chi 06 | Conference on 60 Years of Yang-Mills Gauge Field Theories: Chris Ong CN Yang’s Contributions to Physics Louis Lim Charlotte Wee Maitri Bobba 10 | CN Yang Scholars’ Informal Dialogue with Nobel Laureate Raymond Liu Prof Chen-Ning Yang Erin Ong

15 | 2nd Singapore Sustainability Symposium: Sustainable City Design

18 | 2015 World Science Conference Israel with Nobel Laureates and Renowned Researchers

22 | Nobel Laureate Prof Eric Cornell’s Visit to SPMS, NTU

NOBEL LAUREATE PUBLIC LECTURES 23 | Public Lecture by Nobel Laureates and Eminent Scientists: Personal Perspectives on Physics

OTHER EVENTS 26 | Accélérateur de Science: CN Yang Scholars’ Visit to CERN

29 | International Workshop on Higher Spin Gauge Theories

31 | Quantum Physics in Modern Technology

SPECIAL ARTICLE 33 | Critical Point From Wrong to Right

FORTHCOMING EVENTS

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The 2nd Pan Asia Liberal Arts Education Conference, 28 to 29 October 2015

he Institute of Advanced Studies and College of Humanities, Arts and Social Sciences (CoHASS) Tat NTU jointly organised the 2nd Pan Asia Liberal Arts Education Conference from 28 to 29 October 2015 at the Nanyang Executive Centre. The 1st Liberal Arts Education Conference was organised by Prof Fujia Yang (University of Nottingham Ningbo China) in April 2014 and it was a resounding success. This second conference featured a distinguished panel of experts from China, South Korea, Hong Kong, Macau, Taiwan, India, Philippines and Singapore. Co- chaired by Prof Phua Kok Khoo (IAS) and Prof Alan Chan (CoHASS), the Opening Ceremony was graced by Prof Guaning Su, Emeritus President of NTU. Over the two-day conference, the distinguished speakers shared their insights and thoughts on the topic of critical importance to future human development.

In his presentation on “Promoting Cultural Diversity, Prof Alan Chan (Dean, College of Humanities, Arts and Social Integrity and Global Leadership in KAIST Education”, Prof Sciences, NTU) speaking on the challenges and opportunities Steve Kang (President of Korea Advanced Institute of for the Arts and Humanities in NTU. Science and Technology) highlighted Korea’s higher education system, which placed heavy emphasis on technical education and specialisation. While it was the driving force for Korea’s rapid economic growth in the 20th century, Prof Kang said that the nation’s unhealthy fixation over college exams had led to a skewed emphasis in education. More than just providing students with technical know-how, universities today must groom graduates who are global citizens: creative, knowledgeable in current affairs and capable of effective communication across cultures.

Going to another part of Asia, Prof Anita Patankar (Director, Symbiosis School for Liberal Arts) described her experiences of liberal arts education in India. In her talk titled “Looking Towards New Models of Liberal Arts Education for National Development”, Prof Patankar commented how the phenomenon of globalisation has changed almost every aspect of life as we know it, including higher education. She closely examined the Prof Fujia Yang (President, University of Nottingham Ningbo China) need for undergraduate colleges to explore the option discussed the Copenhagen Spirit and Liberal Arts Education.

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of incorporating liberal arts philosophy in the curriculum as part of the process of learning to adapt to the changes brought about by rapid globalisation.

Closer to home, Prof Pericles Lewis (President of NUS- Yale College)’s talk on “Innovation in Liberal Education” discussed how Singapore’s first liberal arts college, NUS- Yale College, through innovative means, had incorporated both Asian and Western influences in humanistic, social, and scientific studies, to create a common curriculum for their students. In such an environment, students are encouraged to be risk takers, to experiment, and challenge themselves to go beyond their comfort zones.

The presentations by all the speakers were illustrated vividly with examples of student activities and exciting recounts from each speaker’s personal experiences.

The highlight of the conference was the roundtable Prof Chia-Wei Woo (Founding President, Hong Kong University of discussion on “Liberal Arts Education in the 21st Century”, Science and Technology) engaging in the conference discussion.

Panellists of the roundtable discussion. (From left) Profs Anita Patankar (Director, Symbiosis School for Liberal Arts), Alan Chan (Dean, College of Humanities, Arts and Social Sciences, NTU), Peihua Gu (Provost, Shantou University), Fujia Yang (President, University of Nottingham Ningbo China), Wei Zhao (Rector, University of Macau), Kenneth Young (Former Pro-Vice-Chancellor, The Chinese University of Hong Kong), Ka Ho Mok (Vice President, Lingnan University) and Xiaofeng Jin (Fudan University). The discussion was chaired by Prof Da Hsuan Feng (standing), Director of Global Affairs and Special Advisor to Rector, University of Macau.

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Speakers and participants of the 2nd Pan Asia Liberal Arts Education Conference.

Prof Phua thanking the guests for their The guests enjoyed a sumptuous feast and excellent performances by young musical participation during the dinner banquet talents at the dinner banquet. at Shangri-La Hotel.

chaired by Prof Da Hsuan Feng (Director of Global audience participated actively in the discussion, giving Affairs and Special Advisor to Rector, University of their views from their perspectives as principals, Macau). The panellists gave their views on liberal arts educators and even students. education and in particular, “Asian Liberal Arts Education” as asked by the audience. The lively discussion reviewed All in all, over 100 participants attended the two-day the need for liberal arts education in Asian universities, event, including high school students, undergraduates and possible alternative models of liberal arts education and interested members of the public. The speakers and that are specifically tailored for an Asian context, as guests were also treated to a sumptuous banquet and opposed to using the standard model of liberal arts musical performances at the Shangri-La Hotel. education that originated from the US. The engaging

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Conference on 60 Years of Yang-Mills Gauge Field Theories: CN Yang’s Contributions to Physics by Lars Brink Chalmers University of Technology

n 1954, Prof Chen-Ning Yang spent some time at was published in the Physical Review. It was criticised Brookhaven National Laboratory where he met directly by Wolfgang Pauli and others who argued that IRobert Mills. They decided to study an extension of the vector particles would be massless leading to long- Quantum Electrodynamics, where the local symmetry, range interactions that was in contradiction to the the gauge symmetry, was a non-abelian symmetry experimental facts about the strong interactions. The algebra, SU(2), with three vector bosons mediating the interest in the paper was not so strong in the beginning. forces between a doublet of matter particles. The symmetry that the authors had in mind was the isotopic Two years later, Yang together with Tsung-Dao Lee made symmetry and hence this was a prototype model for the the revolutionary discovery that parity might not be strong interactions between protons and neutrons. The conserved in the weak interactions, a fact that was mass of the vector bosons was zero classically and the quickly established by Chien-Shiung Wu with authors speculated that they might obtain masses during collaborators, and the Nobel Prize in physics for 1957 was quantisation. On 1 October 1954 the Yang-Mills paper awarded to Yang and Lee. This opened up the detailed

Nobel Laureate Prof Chen-Ning Yang reminiscing about the early days of particle physics.

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study of the weak interactions and to a phenomenological QCD. This took longer to establish but all experimental model called the V-A theory by Richard Feynman and results in the 1970s and 1980s led to the conclusion that Murray Gell-Mann and Robert Marshak and George this is indeed the correct model. By now we have the Sudarshan. Standard Model based on these two Yang-Mills Theories which have been tested experimentally to a very high During the 1960s, most attention in particle physics was degree. We see that the proposal from Yang and Mills is on the classification of particles but attempts were made indeed the correct theory for the particle physics that we to use the Yang-Mills Theories. In 1964, Robert Brout and can measure at the large accelerators. François Englert and Peter Higgs found a mechanism to use spontaneous symmetry breaking pioneered by We can now safely say that in the 60 years since the Yang- Yoichiro Nambu to show that a Yang-Mills Theory could Mills Theory was proposed, it has become the cornerstone indeed lead to interactions with short range. They still of theoretical physics, being the foundation of the had the strong interactions in mind. In 1965, Moo-Young Standard Model of Particle Physics, but it has also had Han together with Nambu proposed a Yang-Mills Theory important applications in statistical physics, condensed with quarks (with colour but integer charges) as the matter physics, nonlinear systems and not the least in matter particles and an SU(3) gauge symmetry for the pure mathematics. In the hands of Edward Witten the strong interactions. Finally in 1967 and 1968, Steven supersymmetric Yang-Mills Theories have opened up Weinberg and Abdus Salam used the mechanism new avenues in mathematics, which have led to much invented by Brout, Englert and Higgs and proposed a closer links between physics and mathematics. Yang-Mills Theory based on the gauge group SU(2)x U(1) as a unified theory for the electromagnetic force together The discovery of the Yang-Mills Theory was one of the with the weak interactions. This model lay dormant till most important discoveries of the last century and even 1971, when Gerard ‘t Hooft and Martinus Veltman in a though Chen-Ning Yang got the Nobel Prize for his series of papers showed that the Yang-Mills Theories discovery of the parity violations, the future history will were indeed renormalisable, which made the Weinberg- tell that among many great discoveries of his, the one on Salam model a serious candidate for a true model of the the Yang-Mills Theory was his greatest achievement. electro-weak interactions, a fact that was established during the 1970s. In 1973, David Gross and Frank A historic conference “60 Years of Yang-Mills Gauge Field Wilczek and David Politzer showed that a Yang-Mills Theories” was held from 25 to 28 May 2015 at the Institute Theory is also asymptotically free, which led to the of Advanced Studies, Nanyang Technological University proposal of a theory like the one proposed by Han and in Singapore. Many eminent speakers who attended the Nambu but with fractionally charged quarks as a theory conference included the originator of the theory, Prof for the strong interactions, Quantum ChromoDynamics, Yang himself, and Nobel Laureate David Gross together with Lars Brink, Michael Fisher, Paul Chu, Ludwig Faddeev, Tai-Tsun Wu, Tony Zee, Sau- Lan Wu, Kazuo Fujikawa, George Sterman, Michael Creutz, Henry Tye, Burt Ovrut, Tohru Eguchi, Yong-Shi Wu, Hong-Mo Chan, Sheung-Tsun Tsou and many other eminent speakers.

As examples of the variety of important results reported by the speakers, one can mention the talk by Sau-Lan Wu about the discovery of the gluon, the mediator of the strong Nobel Laureate Prof David Gross (right) engaging in a light-hearted discussion with Profs Lars interactions. David Gross Brink (former Chairman of Nobel Physics Committee), Guaning Su (President Emeritus, NTU) talked about QCD, the perfect and Nobel Laureate CN Yang.

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Participants posing for a cheerful group photograph.

Roundtable discussion on International Collaboration. Chaired by Prof Ngee-Pong Chang (standing), the panel speakers were (from left) Profs Henry Tye (IAS, Hong Kong University of Science and Technology), Hishamuddin Zainuddin (Universiti Putra Malaysia), Auttakit Chatrabhuti (Chulalongkorn University), Yifang Wang (Institute of High Energy Physics, CAS), Lars Brink (Chalmers University of Technology), Nobel Laureate David Gross, Phua Kok Khoo (Director of IAS) and Ching-Ray Chang (National Taiwan University.)

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Yang-Mills Theory. Lars Brink discussed the maximally Comments from some participants: supersymmetric Yang-Mills Theory which is a quantum mechanically finite quantum field theory, a property few “As an undergraduate student, the conference was neither overly believed before could exist. It is also dual to the technical nor pedagogical. Rather, an introduction along with the Superstring Theory and hence carries information about history and rules played by various parties, to many of the field quantum gravity giving the hope that quantum gravity which Prof Yang contributed to, was not only interesting, but is associated with Yang-Mills Theory. George Sterman exceptionally meaningful and enriching. Thank you for organising talked about Quantum ChromoDynamics at very high such a wonderful conference, Prof K. K. Phua and team!” energy and Michael Creutz gave a lecture about lattice gauge theory which is an important alternative way to - Tan Jing Long find non-perturbative solutions. Undergraduate Student, University of Oxford Also Chen-Ning Yang’s many important contributions to statistical physics were reviewed and “the grand old man” of statistical physics Michael Fisher gave an exposé “Nothing is more encouraging than learning theories from those of statistical physics in the oeuvre of Chen-Ning Yang. who discovered it!”

The conference included also interdisciplinary talks by - Liu Zheng Paul Chu on “A Possible Paradigm-Shift in the Search for Undergraduate Student, Higher Tc”, Robert Crease on “Yang-Mills for Historians Physics and Applied Physics, NTU and Philosophers”, and on “Folding Proteins at the Speed of Life” by Antti Niemi. There were also reprises of Chen- Ning Yang’s contributions to physics by Yu Shi and “The conference was very informative and I got the chance to know Zhong-Qi Ma. much about the great CN Yang and his invaluable contributions to the world. Also, the discussions with people during the conference As the Yang-Mills paper was written when Yang and gave me an insight to know about different perspectives and new Mills shared an office during the summer at Brookhaven ideas about the future directions of my research work.” Lab, the conference included a roundtable discussion on the role of regional labs and hubs in the promotion of - Deobrat Singh collaboration in theoretical and fundamental physics. PhD Student, Panellists were David Gross, Lars Brink, Phua Kok Khoo, University of Delhi Ching-Ray Chang, Auttakit Chatrabhuti, Henry Tye, Yifang Wang, and Hishamuddin Zainuddin. Various suggestions were made during the discussion, including strong arguments for creating an Asian version of CERN where Asian countries together with scientists from the rest of the world would be able to work collectively to uncover new levels of fundamental physics.

The conference was organised and chaired by Phua Kok Khoo and Lars Brink. Over 180 participants attended, from Europe, US, India, China, Japan, Korea, Australia, and Southeast Asia.

A delightful atmosphere at the banquet in Chui Huay Lim Club.

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CN Yang Scholars’ Informal Dialogue with Nobel Laureate Prof Chen-Ning Yang, 27 May 2015

Five CN Yang Scholars from Nanyang Technological University had the privilege of engaging in an informal discussion with Nobel Laureate Prof Chen-Ning Yang. Centring on the topics of inspiration and research, Prof Yang dispensed advice for the scholars with some humour.

Prof Yang: Let me say something. I think everybody has his 90s. His greatest work was a paper that was published some speciality in some things. Some of these are in 1944, called ‘A simple intrinsic proof’. obvious, others are somewhat hidden. If you pay attention, you may find that there are some things that Throughout his life, he said that this was his greatest you are particularly interested in. It is good for you to contribution, and it was, because with this theory, it was think about it, analyse it, and see whether it is a direction possible to find new features of different branches of that is worth exploring further. mathematics: geometry, algebra, analysis and topology. All of these four areas of mathematics are deeply related I will give you two examples. You know, one of the great to this simple paper which was only seven pages long. mathematicians of the 20th century was Prof Chern How did he produce these seven pages? As a graduate Shiing- Shen, who was born in 1911 and passed away in student, he was very interested in a well-known theorem

Prof Chen-Ning Yang engaging in discussion with the CN Yang Scholars.

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called the ‘Gauss-Bonnet theorem’. The ‘Gauss-Bonnet Later with proper new stimulation, you may be able to theorem’ is a generalisation of the ‘Euler characteristics’. twist it around and create a new direction of research. Do any of you know about the ‘Euler characteristics’? A cube has 6 faces, 8 corners and 12 edges. Next consider a Erickson Tjoa: My question is, sometimes it gets very tetrahedron or an octahedron or an icosahedron or even hard to pick out a meaningful and interesting question a bigger solid. It need not be a regular solid, it can be an with so much information. Some of them have progressed irregular solid but is formed out of cutting planes. For so much that we cannot see an open question that we can each of these solids, you will have three numbers, the even understand. So how do we match the fact that we number of corners C, the number of edges E, and the have to look for interesting questions? number of faces F. As you may already know, centuries ago, Euler formulated a theorem: Prof Yang: I do not think there is any general rule. Let C-E+F=2 me give you an example of a successful idea. When I was for any such solid. This beautiful simple theorem got at Stony Brook, a distinguished mathematician, Prof generalised in the 19th century and formed a differential James Simons, who was the chairman of the mathematics geometry theorem called ‘Gauss-Bonnet’. Chern was department and is 15 years younger than me, went to very interested in this theorem. He felt that this theorem Wall Street around 1980s and became a billionaire. He is was very beautiful, so he kept on thinking about it and currently one of the leading hedge fund managers in the then realised that a new differential geometry technology world. So I asked him, “What is the secret of your success invented by a great French mathematician Élie Cartan as a fund manager?” He said, “Usual fund managers could be used to simplify its proof. would look at stock information every day and formulate their speculations about the future.” He added, “That is In 1943, he went to Princeton and a friend of his, a few not enough, I need massive data.” So he hired around 50 years older, a great mathematician, named André Weil, PhDs in physics and mathematics working for him. They showed him a paper of more than a hundred pages all collect information, not daily, not hourly, but every which generalised the ‘Gauss-Bonnet theorem’ to a five minutes. One of them may be specialising in energy higher dimension. It was a very complicated paper, but stocks, and he would collect information for energy it contained an integral. With Chern’s interest about the stocks every 5 minutes. Others do it similarly for ‘Gauss-Bonnet theorem’ and with his knowledge of the chemical stocks. It is out of that massive amount of mathematical method he had learnt from Élie Cartan, he information that they perceive certain patterns. They had studied this integral and within two weeks wrote that seminars like physics seminars and one of these PhDs seven-page paper which revolutionised mathematics. may say, “I see certain patterns”, and they would discuss it and arrive at a majority view. If these patterns were Let me give you a second example. We were talking at likely to be correct, they would make a massive this conference about my contribution called the ‘Yang– Mills theory’. How was it that I did formulate that theory with Mills in 1954? When I was a graduate student in Kunming, there was already a theory called ‘Gauge theory’ of electromagnetism. It was very simple and very “If there is something which beautiful, though not very useful. Somehow I felt that intrigues you, which you think is this was something that I cared about, and gave my attention to it. Later when I was in Chicago, new very beautiful or very elegant or experiments showed that there were many new particles. very powerful, think more about it, So I asked, “There are so many new particles. They will get thoroughly acquainted with it. have interaction with each other. What is the principle of Later with proper new stimulation, how they interact?” Since I had liked the ‘Gauge principle you may be able to twist it around for electromagnetism’ in Kunming, it was natural to try to generalise this simple principle to other interactions. and create a new direction of That led to the 1954 paper with Mills. research.” Prof Chen-Ning Yang If there is something which intrigues you, which you Nobel Laureate in Physics 1957 think is very beautiful or very elegant or very powerful, think more about it, get thoroughly acquainted with it.

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investment into that particular stock. It was a new kind impossible. Physics has already fragmented into an of analysis using massive amount of data and enormous number of subfields. For you that is a mathematical theories. tremendous disadvantage, but it is also a tremendous advantage: In every one of these subfields, you might be When I was a graduate student in Chicago, the great able to do some very important things. There are many Enrico Fermi always had lunch with us and we always more channels of success waiting for you to try. asked him: “Should we tackle big problems or small problems?” His answer was: “Tackle small problems Smrithi Keerthivarman: How intuitive or how easy is most of the time, and only tackle big problems it to go against what the general scientific community occasionally.” I followed that advice. I think it was a very believes in? Because, going back to your non- good advice. The problem that Dr Zhong-Qi Ma reported conservational theory, it was not easily accepted by most on was a very special problem, and those are the types of people. How much did you believe in it and how easy or problems that I tackle most of the time. The advantage of difficult was it? tackling small problems is that it is easier, and not many people knew about these small problems, so you have a Prof Yang: We certainly believed, as everyone else, in chance of making a kill. If you tackle a big problem that parity conservation. Thus we did not start with any idea has already been worked on by hundreds of people, your to make a revolution. But we wanted to solve a puzzle, chance of hitting the right button compared with the so called theta-tau puzzle. So we examined the details predecessors is small. of each step invoked in the arguments that led to the puzzle. Finally we found one weak step: the experiments I also want to say another thing. Compared with the time that were believed to establish parity conservation in when I was a graduate student, physics is now more weak interactions were not correctly analysed complicated. As a graduate student, if I study five theoretically. That was the key breakthrough. physics fields, for each of them if I learn the fundamentals, I was already, in some sense, at the top of the fields of Next we suggested new more complicated experiments physics. Physics only had five big areas at that time. If to test parity conservation. One of these more complicated you do well in those five areas, you would feel that you experiments was what Prof Chien-Shiung Wu chose to are more or less at the top at that time. Today it is do. At that time, she was one of the greatest experts in

Prof CN Yang sharing his words of wisdom with the scholars.

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beta decay. She performed one of these more complicated students came in with a beaker with a big crystal in it. experiments which took her half a year. Everybody was extremely happy and said, “How did you make this big crystal?” Upon examining what Actually Lee and I had fully expected that she would happened during the previous day, they found that prove that parity was conserved, because that was what student had taken the beaker home and accidentally we all had believed. When it showed that that was not placed it near the oven. Thus it is best to put the beaker true, we all knew she performed a very very important of liquid in some warm place. So you see, all successful experiment. experiments consist of collections of ups and downs.

Smrithi Keerthivarman: So you did not expect it at all Ji Dongxu: Research is very taxing and stressful, did you until the very end? experience any period of unsuccessful research?

Prof Yang: We did not expect it. She did not expect it. I Prof Yang: Of course I had. When I went to Chicago, I think nobody expected it. Most people said it was a waste was determined to write an experimental PhD thesis of time. She should not do it because she was bound just because I said to myself, “I have learnt a lot of theory in to find conservation of parity. Prof Wu’s great China but not a lot of experiments, and I knew physics achievement lay in her perception that this was an must be based on experiments. So I wanted to write an experiment that was worth doing even though she did experimental thesis.” At first I wanted to work with not expect any revolutionary results. Enrico Fermi, but I could not because Argonne National Laboratory where Fermi was based did not allow foreign Prof Oh: Prof Yang, this issue has already crossed 50 nationals. So I worked with Prof Allison for 20 months years? That should have passed the Nobel Prize 50 Year and learnt that I was clumsy. More importantly when we Secrecy Rule. So the Nobel committee should explain were in the laboratory, there were a lot of problems. why Prof Wu did not get the prize. Problems like some things did not work and I did not know how to fix them. My fellow graduate students Prof Yang: It used to be said that 50 years after the event, knew how to fix them. So in some aspects, I developed a historian of science would be allowed to look at the an inferiority complex, but on the other hand, I could records of the Nobel Committee. Although it has been solve mathematical problems for my fellow graduate more than 50 years after 1957, I believed they have students, so we had good relationships and helped each changed the rules. Now it has to be at least 50 years and other. But after 20 months, I knew I was not made for also has to be when all the people involved have passed experimental physics. It happened that I had written a away. theoretic paper and Edward Teller, who was my theoretical advisor, said, “That paper is quite good. You Do you know how Prof Wu initialled her experiment? make it a little bit longer and I will accept that as your PhD thesis.” After debating with myself for a few days, Her experiment was very difficult because it combined I decided that he was right. So I abandoned experiments two technologies, beta decay and low temperature and came back to theory. That experience also taught me physics. She also needed to be very precise in her that indeed a person should not be so stubborn as to try experiment because of the low temperature requirement to do something that he or she is not destined for. and the fact that the source of radioactivity is cobalt. The material has to be in the form of a big crystal. Now, how Prof Oh: Physics is now a very wide discipline, as you to form a crystal is a specialised field. Prof Wu did not said. What area of research do you think will be very know how to form big crystals, so she went to the active in the next years? chemistry department and consulted some chemists. Prof Yang: I think one very important area which I am The chemists gave her a big bunch of books on how to sure will become more and more important in the next form crystals. So she got these books and started reading 20 or 30 years is the application of physics in medicine. I with her students on how to make big crystals. They tried am wearing this hearing aid (referring to his hearing aid). hundreds of bottles of solutions but did not succeed in The technology of hearing aid is at least 50 years old, but getting big crystals. They were very disappointed only recently has it become better. My father was in his because without a big crystal they could not do the 60s when he had hearing difficulties. So we bought for experiment. But one morning, one of her graduate him a pair of hearing aids, but he refused to wear them.

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He complained that the hearing aid amplified everything optics. It is extremely important. You know why Prof Kao and there was too much noise. In the last, maybe 20 years, got the Nobel Prize for fibre optics? hearing aids have improved. Why? Because they now do not just amplify the sound, they make a Fourier Erickson Tjoa: Prof Charles K. Kao? transformation and divide the spectrum into bands. Different bands would be given different amplifications. Prof Phua: Yes, from Chinese University of Hong Kong. For me, I have become more and more insensitive to high frequency. So they amplified the high frequency bands Prof Yang: Prof Charles K. Kao was the President of the and do not amplify as much on the low frequency bands. Chinese University of Hong Kong, and he received the When I first began to wear a hearing aid, there were only Nobel Prize for his thesis on the ground-breaking 6 bands but that was about 12 years ago. These are the achievements concerning the transmission of light in improved ones (referring to his hearing aids), there are fibres for optical communication, while working in 12 bands. Now they also make 18 bands one. Still I think England (Standard Telecommunication Laboratories). even if it has improved to 48 bands, it is still not good What did he do? At that time, I think it was in the late 60s, enough because there are a lot of other problems. For people already thought about transmitting optical signals example, how to hear different consonants clearly will along glass fibres, but it was not considered useful require further research. At the present moment, the because the signals that are being transmitted along the largest company in the world that makes the most glass fibres would dramatically decay in short distances. hearing aids is Siemens. The next largest is a small What Kao did was he analysed the cause of this company in Denmark. Why is a small company in a small attenuation and theorised that glass itself was not the country like Denmark so successful? It is because there problem. It was the impurity in the glass tube. Some were some acoustic physicists in Denmark. Starting from years later, when glass companies started to make purer that, they formed an industry. glass fibres, they found out that he was correct. The purer the glass fibre is, the lesser attenuation there will be. So Fibre optics is another good example. I think many that is why he later received the Nobel Prize in 2009. It is hospitals would have to close their doors if not for fibre another successful story.

(Front row from left) Profs Phua Kok Khoo (Director, IAS NTU), Nobel Laureate CN Yang and Oh Choo Hiap (NUS). (2nd row from left): Ji Dongxu, Erickson Tjoa, Christofer Kristo, Ray Fellix Ganardi, Smrithi Keerthivarman, Hartono Wijaya and Sun Han.

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2nd Singapore Sustainability Symposium: Sustainable City Design by William Clune Sustainable Earth Office, NTU

he Nanyang Technological University’s (NTU) more sustainable Singapore with its EcoCampus Sustainable Earth Office (SEO) and The Institute of program, academic research, leadership in Cleantech, TAdvanced Studies (IAS) were the front runners in teaching excellence, and many others. the organisation of the second Singapore Sustainability Symposium (S3) that was held from 15 to 17 April 2015 The introduction and opening addresses were followed at The Regent, Singapore. The Ministry of Health, by a panel discussion moderated by Prof Alexander Ministry of National Development and the Ministry for Zehnder (Chair of NTU’s Sustainable Earth Office). The Environment and Water Resources, Singapore lent their panellists included Mrs Tan Chin Yee (Permanent support and collaboration in making the event a success. Secretary, Ministry of Health), Mr Peter Ho (Visiting Professor, Lee Kuan Yew School of Public Policy and The title for S3 2015 was, ‘Sustainable City Design’. former Head, Civil Service, Singapore), Ms Birgit Simon Similar to its first symposium, the discussions and (Deputy Director, Regional Authority Frankfurt Rhein/ takeaway from the second S3, served as early inputs to Main, Germany) and Dr Peter Edwards (Director, the World Cities Summit 2015 and Mayor’s Forum (June Singapore-ETH Centre, Singapore). 2015, New York). S3 has now become an international platform with a Singaporean flavour for sustainability and urban solutions with a special interest in the challenges faced by cities and city decision makers.

This year’s symposium began on the evening of 15 April 2015, with a public lecture and roundtable discussion panel. The Guest of Honour, Permanent Secretary (Environment and Water Resources) Mr Choi Shing Kwok presented some key objectives from Singapore’s new sustainability plan. He outlined the important areas of development and change that are being put in place for a more sustainable future. NTU President, Prof Bertil Andersson graced the occasion and shared how NTU contributed toward a Prof Bertil Andersson (NTU President) outlining NTU’s contributions toward a more sustainable Singapore.

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The primary addresses by all panellists were informative, Session Two: Technology and Innovation followed by an internal discussion between the experts. The discussion was then open to the floor which garnered Session Three: Urban Footprint and Regional Security many questions from recycling of waste to efficient uses of water. Session Four: Financing Sustainable Cities

As with previous years, S3 focused on the discussions Some of the key takeaways for presentation at the June over its two days of sessions, driven by a main table and forum in New York included: supported by local and international delegates from the surrounding tables. Each session revolved around pre- • Cities will play an increasingly important role in determined topics: addressing adaptation challenges, as the impact will be felt most severely and they are often in the best position Session One: Cities, Adaptation, and Action Now! to implement high-impact solutions.

Panellists with Prof Bertil Andersson (NTU President) after a fruitful panel discussion on Water Recycling: (From left) Prof Peter Ho (Former Head of Civil Service, Singapore), Prof Birgit Simon (Deputy Director, Regional Authority Frankfurt Rhein/Main, Germany), Mr Choi Shing Kwok (Guest of Honour and Permanent Secretary, Ministry for Environment and Water Resources, Singapore), Prof Peter Edwards (Director, Singapore-ETH Centre), Prof Bertil Andersson (NTU President), Mrs Tan Ching Yee (Permanent Secretary, Ministry for Health, Singapore) and Prof Alexander Zehnder (Chair of NTU’s Sustainable Earth Office).

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One of the highlights of the symposium: Panel discussion on Water Recycling.

• Cities need champions and leaders to drive sustainability leaders understand the connected roles of technology, agendas and solutions forward. These champions should governance, and financial markets. move beyond the foundation of immediate cost and logistics planning to describe a vision of what future and • The implementation of sustainability solutions, liveable cities could become. innovative approaches, and new technologies in cities should be more inclusive, equitable, and culturally • Research, science, and R&D will continue to provide appropriate in order to ensure acceptability by different concrete and relevant information to support decision- social groups. making and action in cities. As the symposium grows in strength from year to year, • It’s never a question of needing better governance or much interest has been expressed toward the continuous more technology; because the two go together and we organisation of this platform to be an international need much more of both; society changes, technology exchange of ideas and strategies. The global representation responds, and technology is constantly changing society. of speakers, delegates and professionals who attended added to the constructive deliberations. With the • Technology’s best potential is with sustainability participation of Government bodies, the symposium projects that are applied, visible, demonstrable, and highlighted the importance of sustainability and city acceptable to stakeholders as being culturally appropriate. design to Singapore and all of Southeast Asia.

• Education is key for promoting technology and Planning is now underway for the Third Singapore innovation, in changing hearts and minds, in training Sustainability Symposium, to be held in April 2016. We entrepreneurs and engineers, and in helping future are looking forward to another successful collaboration!

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2015 World Science Conference Israel with Nobel Laureates and Renowned Researchers

by Timothy Yap CN Yang Scholar, NTU

rom 15 to 21 August 2015, five students from the Held at The Hebrew University, Givat Ram Campus in CN Yang Scholars Programme in Nanyang Jerusalem at the height of the Middle Eastern summer, FTechnological University visited Israel to join the week-long event was graced by the presence of 14 nearly 400 delegates from 70 countries around the world Nobel Laureates in Physics, Chemistry, Economic for the 2015 World Science Conference Israel, celebrating Sciences, and Physiology and Medicine, and a Fields scientific achievement and fostering interdisciplinary Medallist. There were namely, Prof Zhores Alferov dialogue and cross-national cooperation. The educational (Nobel Laureate in Physics 2000), Prof Sidney Altman trip was supported by the Institute of Advanced Studies (Nobel Laureate in Chemistry 1989), Prof Robert Aumann and the CN Yang Scholars Programme Director’s Office (Nobel Laureate in Economic Sciences 2005), Prof Aaron at NTU. Ciechanover (Nobel Laureate in Chemistry 2004), Prof

Nobel Laureate Prof Roger Kornberg, Chairman of the WSCI Academic Committee, delivering the welcome address.

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Steven Chu (Nobel Laureate in Physics 1997), Prof to hang on to our dreams. “Science has no borders,” he Claude Cohen-Tannoudji (Nobel Laureate in Physics concluded. 1997), Prof David Gross (Nobel Laureate in Physics 2004), Prof Roger Kornberg (Nobel Laureate in Chemistry Prof Ada Yonath highlighted the need to be humble, for 2006), Sir Prof Harold Kroto (Nobel Laureate in Chemistry instance thanking her Swedish chauffeur in her Nobel 1996), Prof Richard Roberts (Nobel Laureate in Physiology Prize acceptance speech in 2009. She also expressed or Medicine 1993), Prof Dan Shechtman (Nobel Laureate delight at the leaps and bounds that science had made in Chemistry 2011), Prof Harold Varmus (Nobel Laureate since her youth, citing the example of DNA – “when I in Physiology or Medicine 1989), Prof Arieh Warshel was your age, DNA was just discovered. Now they tell (Nobel Laureate in Chemistry 2013), Prof Ada Yonath young students that DNA is used by the police to identify (Nobel Laureate in Chemistry 2009) and Prof Elon criminals.” Being the only woman among the fifteen Lindenstrauss (Fields Medallist 2010) eminent guests invited to the event, she also took care to mention that women could make great scientists and The opening ceremony was held on the first night, 16 mothers, citing various women working in her lab. August 2015. There were performances by mentalist Lior Suchard and the famous Israel band Mayumana. The Prof Zhores Alferov recalled the inspiration he derived themes of igniting imagination, curiosity and inspiring from attending lectures by Nobel Laureate John Bardeen the next generation of scientists perpetuated throughout when he was at the University of Illinois. Prof Alferov the whole opening ceremony. There was a segment where the audience was brought back in time to “meet” three revolutionary individuals: Albert Einstein, Archimedes and Leonardo Da Vinci who gave pertinent pointers to the next generation of aspiring young scientists. Next, there was an address by the 9th President of Israel, Shimon Peres, who gave an introduction of the importance of the conference to Israel and the rest of the countries present during the conference. He mentioned that good science takes place when people from different parts of the world come together to collaborate and exchange ideas, and the WSCI was the ideal opportunity to do so.

Prof Roger Kornberg, the Chairman of the WSCI

Academic Committee gave a talk about his love for Melodious harp performance by Israeli musician Ben Grossman at science. He urged us to not try and emulate the older the opening ceremony. scientists or teachers, but rather to chart our own course and question what we have heard. The role of the scientist, he said, is “only to expand knowledge and to satisfy our curiosity, and it is up to society to use that knowledge and prescribe its use”. He also shared what he thinks is the beauty of science: that the conclusion you reach is always more elegant, more ingenious, and different from what you expect.

Shimon Peres, the former President and Prime Minister of the State of Israel, gave us his thoughts on science in a surprise video message. “Science is more important today than politics,” he urged, for science has changed and revolutionised our way of life. “In the age of science, you can become greater not by taking from others. You can do it yourself. You don’t need to create enemies.” He The Singapore delegation comprises 5 CN Yang Scholars (from urged us to leave the past behind and join the future, and left), Timothy Yap, Qian Qihui, Claudy Andriani, Melissa Tan and Yang Jingfan.

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cautioned that sometimes science can be mishandled to discovered. Prof Ciechanover shared that challenging the destroy lives, like the “most terrible weapon” – hydrogen authorities is also important – he likes the fact that bomb. Scientific advancements can still be covered up sometimes the workers in his lab tell him that his ideas and stifled, such as the Teller and Ulam’s hydrogen bomb are stupid. report which is classified in the USA. Despite that, many advances in nuclear physics were made. The new Prof Steven Chu was the United States Secretary of heterostructure solar cells can achieve up to 46% Energy from 2009 to 2013, working under fellow Nobel efficiency, and he hopes that the future of energy will be Laureate President Barack Obama. He mentioned how solar. he wanted a brief sabbatical from his scientific work, and wound up managing large amounts of money for Separately, Prof Harold Kroto gave a talk about his scientific research. Ultimately, he shared that he missed discovery of buckyballs – buckminsterfullerene, to be the work that he had done in science. “You start by precise. He mentioned that one of the most important scrounging, reading, going to a lab that has the equipment; qualities of being a good scientist is to never accept a you don’t start off with asking for one million bucks.” As hypothesis without evidence. “Scientists have a such he believes that passion will drive curious minds to responsibility to ensure that what we do is for the benefit new experiments, and he likes putting himself at the of the human race. It is important that we try to point out forefront of scientific research. facts to help those in power to make the right decisions,” Prof Kroto urged. Scientists are also linked in a way that Prof Dan Shechtman recounted his “accidental” discovery no other cultures are, he pointed out. of quasicrystals and how he overcame a lot of opposition from his peers and finally winning the Nobel Prize. His Prof Aaron Ciechanover spoke of his being a first-year presentation is a reminder to us aspiring scientists that medical student in 1965. Over the years, the causes of many scientific discoveries require a lot of hard work and death has changed from violent trauma to infectious a little bit of luck. He reminded us that when one diseases, and now to degenerative diseases like cancer or observes something out of the ordinary, one should Alzheimer’s disease. He highlighted the gradual change probe and explore further instead of throwing away that in the identification of drugs – from serendipity, as was piece of data. He also inspired us to stand our ground the case for penicillin, to brute force, like for statins, and against opposition if we are sure that we are correct. He now to personalised medicine. He hopes that personalised mentioned that he encountered great opposition from the medicine can continue to make new breakthroughs for renowned chemist Linus Pauling. However, despite medicine, and that new, hidden challenges will be years of opposition, Prof Dan Shechtman asserted that

Panel discussion on “Eureka Moment!” chaired by TV presenter Gil Hovav (left) with Profs Hanoch Gutfreund (Andre Aisenstadt Chair in Theoretical Physics, Hebrew University of Jerusalem), Nobel Laureates Arieh Warshel (Chemistry 2013), Harold Kroto (Chemistry 1996) and Sidney Altman (Chemistry 1989).

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his claim is indeed true – that quasiperiodic crystals do exist. Currently, there are many examples of quasiperiodic crystals with one big field of scientists pushing the “Once a fundamental question boundaries further. becomes a well-formulated scientific Prof David Gross believes that all good scientists must question, then it will be answered be optimists; otherwise they would have given up too in your lifetime. Once a technically easily. “Once a fundamental question becomes a well- feasible instrument is formulated, it formulated scientific question, then it will be answered in your lifetime. Once a technically feasible instrument is will be built in your lifetime.” formulated, it will be built in your lifetime.” He cited the Prof David Gross example of Albert Einstein, who believed that there will Nobel Laureate in Physics 2004 be further fundamental questions after his formulation of General Relativity, and that his equations would be replaced with better equations (as it has). As he put it, “the best is yet to come”.

It was not all lectures for the participants. Before the event, the participants were expected to prepare, in groups of ten to eleven, scientific posters on self-chosen topics ranging from breeding mice in microgravity to using graphene in prosthetics. The conference ended with the poster presentations and the fruitful exchange of ideas.

As Prof Roger Kornberg (Chairman of the WSCI Academic Committee) put it, scientific research respects neither political lines nor national borders. Our Singapore delegation was grateful for the opportunities to establish connections with budding scientists from all around the world at the World Science Conference Israel 2015.

Getting to know each other and forging new friendships with delegates from around the world. “It really is an eye-opening experience for all of us. I wanted to hear the Nobel Laureates speak about their experiences as scientists, and I found Prof Harold Kroto’s presentation the most interesting. Speaking to people from all over the world made me realise that science can be a bridge to connect all the nations of the world in the pursuit for a better future.”

- Alex Kennedy New Zealand delegation

“I am proud to welcome all the nations into my country Israel, and it has been an indescribable experience for me. My favourite scientist was Prof Dan Shechtman, as he showed the important qualities to be a good scientist, and tenacity, perseverance, and sometimes luck can play a factor as well.”

- Matan Ben-Asher A delighted Melissa Tan (CN Yang Scholar) receiving her Israeli host “Eureka!” group’s winning certificate from Mr Guy Kivetz, a representative of the Ministry of Foreign Affairs, Israel.

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Nobel Laureate Prof Eric Cornell’s Visit to SPMS, NTU by Tan Hui Min Evon Centre for Quantum Technologies and Rainer Dumke SPMS, NTU

rof Eric Cornell was awarded the 2001 Nobel Prize interests of JILA community began to expand to areas in Physics with Prof Carl Wieman and Prof unrelated to astrophysics: atomic, molecular and optical PWolfgang Ketterle for the achievement of Bose- physics, biophysics, chemical physics, nanosciences and Einstein condensation in dilute gases of alkali atoms, and the like. The main theme that forges the groups together for the early fundamental studies of the properties of the has always been precision measurement. The faculty has condensates. He is currently a member of the National done excellent research work producing at least two Institute of Standards and Technology (NIST). He is also Nobel Laureates in Physics. Professor Adjoint in the Physics Department of the University of Colorado (CU), and Fellow of Joint Institute Prof Cornell’s work on Bose-Einstein Condensation has for Laboratory Astrophysics (JILA), a joint institute of been recognised by a number of prizes awarded, NIST and CU. including the Samuel Wesley Stratton Award from NIST, the Zeiss Award in Optics, the Department of Commerce Prof Eric Cornell was in Singapore for the 22nd Gold Medal, the Fritz London Award for low temperature International Conference on Laser Spectroscopy, so physics, the Rabi Prize of the American Physical Society, Nanyang Technological University’s (NTU) School of the 1997 King Faisal International Prize for Science, the Physical and Mathematical Sciences (SPMS) has the Lorentz Medal in 1998, the R. W. Wood Prize in 1999 and honour of inviting Prof Cornell to visit on 30 June 2015 the Benjamin Franklin Medal in Physics. In 2000, he was through the arrangement of the Institute of Advanced elected as a Fellow of the Optical Society of America and Studies. a Member of the National Academy of Sciences.

He gave a seminar on “Experiments on Degenerate Bose Gases with Unitary Interactions” at the Division of Physics and Applied Physics at SPMS, and interacted with members of the ultracold atom groups led by Prof Rainer Dumke. In his talk, Prof Cornell spoke about the experiments that he and his group members have done at JILA in which they have shown that while a degenerate Bose gas with formally infinite interaction length may decay quickly, its lifetime is long compared to resolution of available laboratory probes of the conditions in the sample. During the presentation, Prof Cornell has described hi experiment in this extreme environment, and compare them to predictions of universal two- and three-body physics.

JILA is an interesting research centre in the United States. Originally, JILA scientists began their scientific exploration on strengthening the field of laboratory Nobel Laureate Prof Eric Cornell (third from left) with SPMS astrophysics. However as time passes, the research faculty members, Dr Paterek Tomasz, Prof Rainer Dumke, Prof David Wilkowski, Dr Gao Weibo and Dr Lan Shau-Yu.

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Public Lecture by Nobel Laureates and Eminent Scientists: Personal Perspectives on Physics

by Christian Zielinski School of Physical and Mathematical Sciences, NTU

n conjunction with the anniversary conference to & Wolf Prize Winner 1980), Prof David Gross (Nobel celebrate 60 Years of Yang-Mills Gauge Field Theories, Laureate in Physics 2004) and Prof Chen-Ning Yang Ithe Institute of Advanced Studies (IAS) at Nanyang (Nobel Laureate in Physics 1957). Technological University (NTU) organised a public lecture on “Personal Perspectives on Physics” on 25 May Prof Michael Fisher gave the first lecture on “Pictures, 2015 at the Nanyang Auditorium. The three distinguished Models, Approximations and Reality: Phase Transitions and speakers were Prof Michael Fisher (Royal Medallist 2005 Our Understanding of the Physical World” with an

Group photo with the distinguished speakers. (From left) Profs Michael Fisher (Royal Medallist 2005), David Gross (Nobel Laureate in Physics 2004), Guaning Su (President Emeritus, NTU), Chen-Ning Yang (Nobel Laureate in Physics 1957), Phua Kok Khoo (Director of IAS) and Lars Brink (Former Chairman of Nobel Physics Committee).

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Prof Michael Fisher delivering his lecture using multiple The audience was enthused by the engaging talks of the three experts charts and photographs to introduce about critical pheno- on their personal perspectives on physics. mena on superfluid and ferromagnetic phase transitions.

introduction to critical phenomena using superfluid and Feynman had an optimistic view and believed that one ferromagnetic phase transitions as examples. These day we would be able to find a “final solution” in examples introduced and elaborated on the concept of understanding the fundamental laws of nature, Prof critical exponents, which describe the behaviour of Yang had and still has a more conservative point of view. physical quantities near the critical temperature. Prof Fisher then used the “Ising Model” with the famous With the ever-growing required budgets and timescales “Onsager Solution” as a simplified, but rich model to for experiments in particular in the field of particle describe ferromagnetism and to connect theory with physics, Prof Yang is worried that progress will eventually experiment. slow down and it might take much more than 50 years to reach a new height in our understanding of the The second talk on “Frontiers of Fundamental Physics” fundamental processes in nature. delivered by Prof David Gross covered a quick overview about our current understanding of the fundamental Question & Answer session forces of nature and several modern concepts in Responding to the question on advices for young theoretical physics such as supersymmetry, grand scientists on their future career path, Prof Fisher said, unification and emergent space-time. Prof Gross also “My basic advice is for you to talk to people and try to dealt with the question regarding whether our progress understand things, and to think for yourself. Do not just in understanding the inner workings of nature will do things that you are interested in and that move you to eventually come to a hold or can we go on forever. want to learn more about. There are infinitely many Despite many challenges and obstacles in the future things to learn about.” He added that young scientists research landscape, Prof Gross remains optimistic and he should not be distracted by the trend and should follow believes that we will continue to widen our knowledge their own instinct instead. of the universe. Regarding the rise of artificial intelligence to replace The last talk of the evening on “The Future of Physics — human on deep learning, Prof Gross shared that artificial Revisited” was given by Prof Chen-Ning Yang. Prof intelligence has already started to replace human in Yang’s talk was inspired by a panel discussion at MIT in certain menial intellectual tasks such as language 1961, where he, together with Profs Francis Low, John translation, call centre jobs, etc, but he highlighted that Cockcroft, Richard Feynman and Rudolf Peierls discussed artificial intelligence would not be able to replace their views on the future of physics. Prof Yang once again scientists or creative mathematicians or physicists in any picked up the original question from the panel discussion time of the near future. He explained that it is currently and outlined his current thoughts on how the field of difficult and not programmable to enable artificial physics will develop in the foreseeable future. While Prof intelligence to possess creative thought.

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Prof Yang highlighted that “interest” was what strikes has something which makes him or her different from him to be motivated throughout his life. He shared his others and it would be good if those special points were wisdom of his success to the audience: “I think that our detected, understood and nurtured.” brains are all constructed differently and different persons have a different inclination to be interested in That evening ended with Prof Yang sharing the advice certain things. To be talented in certain things, it is he received when he was an assistant to Prof Enrico important for the individual as well for the parents and Fermi in the University of Chicago. Prof Fermi told Prof the teachers to try to find that spark of interest on the part Yang to spend most of his time to work on small problems of each young person. If that is found early and if that is and only tackle big problems once in a while which Prof nurtured and developed, it might make future career Yang had followed closely. much easier. I think in many senses, almost every child

Prof Richard Amoroso (Director of Noetic (From right) Prof Guaning Su (President Emeritus, NTU; chairman of the public Advanced Studies Institute) posing question lecture) along with the three renowned speakers, Profs David Gross, Michael Fisher at the Q&A session. and CN Yang.

Prof Guaning Su (President Emeritus, NTU) presenting the memento to Nobel Laureate Prof CN Yang.

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Accélérateur de Science: CN Yang Scholars’ Visit to CERN

by Aaron Lam and Akshay Mamidi CN Yang Scholars, NTU

Located just outside the main cafeteria at CERN is a mock-up fragment of the Large Hadron Collider (LHC), a preview of the 27 km ring lying beneath the France-Switzerland border near Geneva. The scholars were privileged to witness first-hand data produced by the LHC experiments as it reached collision energy of 13 TeV on 20 May 2015.

rom 17 to 21 May 2015, 38 CN Yang Scholars from This educational visit was hosted by Prof Emmanuel the Nanyang Technological University (NTU) Tsesmelis of CERN and sponsored by the Institute of Fvisited the European Organisation for Nuclear Advanced Studies (IAS) and CN Yang Scholars Research (CERN) in Geneva, Switzerland. It was a major Programme (CNYSP) Director’s Office at NTU. The four- milestone for the CN Yang Scholars Programme (CNYSP) day programme was named after CERN’s iconic tagline despite its relatively brief history. “ACCÉLÉRATEUR de SCIENCE”, which means “Accelerator Science” [sic].

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The visit sought to expose CN Yang scholars to a unique as well as to interact with the scientists at CERN that and enriching overseas learning experience at a research motivate and guide such research to fruition. institute unlike any. CERN was naturally the most desirable target for this visit because of the sheer breadth The four-day programme, put together by Natalia Nina and depth of cutting-edge research conducted at its Trajdos of CERN, took us through a series of discussions, premises. The most widely known breakthrough is the lectures, and visits to four major experiments. We were confirmation of the existence of the Higgs Boson particle fascinated by the theory, applications and experimental in 2012 that reconciled our current understanding of the techniques of the works that took place at the world’s Standard Model. The subject of particle physics appealed largest particle physics laboratory. Through conversations greatly to us, both Science and Engineering majors alike, with the guides, we were able to get an insight into the because of its vast variety of theoretical and practical lives, interests and motivations of a CERN researcher. applications — from understanding the very origins of our universe to predicting future trends in climate The first experimental visit was to the Antimatter Factory change. The opportunity to visit CERN was probably that serves as the source of Antiprotons to the LHC and once in a lifetime experience for us to observe the other experiments at CERN. We were introduced to the engineering marvels that made such research possible, existence of antimatter and Charge, Parity and Time

The group of 38 CN Yang scholars gathered in front of the Globe of Science and Innovation, the iconic landmark greeting every visitor to CERN. The Globe houses exhibitions to educate the public on the significant research conducted at this cutting-edge facility.

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(CPT) Symmetry, and the ongoing research that seeks to probe the characteristics of anti-particles and the possibility of parallel universes. The Antimatter Factory, as its name suggests, is also the facility which supplies antiprotons to other experiments at CERN.

The next experimental visit was the Cosmics Leaving Outdoor Droplets (CLOUD) facility. The guides walked us through the detailed process of how an artificial atmosphere could be created in a special chamber from a myriad of adjustable parameters such as humidity, pressure and aerosol content. The guides were passionate in their explanation on how CLOUD investigates the role of different types of aerosols and Galactic Cosmic Rays (GCRs) in cloud formation and ultimately, to obtain a more accurate prediction on the Earth’s climate patterns in the future. The scholars had the opportunities to interact with the scientists The Isotope Separator On-Line Device (ISOLDE) from CERN during the mesmerising visit. experiment was next on the list. ISOLDE is one of the world’s leading laboratories dedicated to the production and investigation of radioactive nuclei. Extensive experiments in the fields of solid-state physics, atomic physics, medical physics, nuclear physics, and secrets the world of particle physics may hold. semiconductors are also conducted at ISOLDE. Incidentally, the final day of the trip coincided with the initial run-up of the LHC at the new, higher energies and What gives matter its mass? This question was answered we were thrilled to be able to observe in real-time the by the visit to the Compact Muon Solenoid (CMS) and A data generated by the LHC on screens mounted in the Toroidal LHC Apparatus (ATLAS), the two famous common cafeteria. particle detectors of the Large Hadron Collider (LHC). It was a humbling experience indeed as we were taken on The trip impressed upon us that years of cooperation a tour through the massive cavern which houses the CMS have allowed CERN to mature into a highly efficient detector. The sheer size of the machinery and the organisation with one purpose: to probe the fundamental dizzying complexity of electronics that sustained the structure of the universe through the study of high- CMS were proof to us of the infinite possibilities energy particle collisions. Through the visit, we were achievable by mankind. Armed with instruments to given a comprehensive walkthrough of the theoretical detect the energies and trajectories of the particles breakthroughs and engineering marvels that with emerging from the collisions in the LHC, these detectors harmonious collaboration, enabled mankind to make were able to independently confirm the existence of the ground-breaking discoveries such as the Higgs boson. Higgs boson particle in 2012 from the indirect observation of decay signatures of resultant daughter particles. We One major lesson learnt from the CERN trip is that got the answer: The newly discovered Higgs boson is a scientists and engineers are never mutually exclusive. It fundamental particle which accompanies an energy field is clear that the manpower equilibrium observed at known as the Higgs Field which is responsible for CERN and the efficiency of research could only be assigning mass to particles. The Higgs mechanism is attained after decades of cooperation. This runs parallel hypothesised to give mass to the elementary particles, to the objective of the CNYSP, to develop its scholars — giving rise to the differences between the weak force and regardless of major — into well-rounded professionals electromagnetism by giving the W and Z bosons mass proficient in both science and engineering. Through this while leaving the photon massless. Beyond the Higgs visit, we have developed fresh insights into the world of boson, both ATLAS and CMS are gearing up to investigate research and are better equipped and inspired to aim collisions at record energy of 13TeV, to see what further high in our own research work in the future.

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International Workshop on Higher Spin Gauge Theories

by Lars Brink Chalmers University of Technology

he four fundamental interactions in Nature are examples of massless higher-spin particles having a self- described by forces mediated by either massless interaction. The calculations were not complete and Tparticles of spin-1 (quantum electrodynamics and further studies showed that if you have one of them you quantum chromodynamics) or massless particles of spin- might need an infinity of them. 2 (gravity) or massive spin-1 particles via spontaneous symmetry breaking, the BEH effect (the weak There was a precursor to this from string theory. There interactions). It was long a question if Nature only allows we have a new length scale and early on, it was asked for these force particles or if interacting theories with what happens if you take this scale to zero. It was then higher spins could also be constructed. In 1983 I found that one gets a Yang-Mills theory coupled to a constructed with my students at the time, Anders gravity theory, i.e. a theory with massless spin-1 and Bengtsson and Ingemar Bengtsson (unrelated) the first spin-2 particles. What happens if one lets this scale go to

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infinity instead? Then it ought to be a theory with an infinity of massless higher-spin fields. No one has ever managed to construct this limit in a satisfactory way but the question is still very much alive.

Higher-spin theories was a dormant field until the end of the 80’s when Mikhail Vasiliev managed to find a new way of studying such theories. He considered them in an anti-de Sitter world which then has a new parameter (like a cosmological constant). He has then found systematic ways of studying the equations of motions for such higher-spin theories and this development has gone on since then and in recent years many new results have been obtained. Prof Murat Gunaydin (Pennsylvania State University) explaining In the late 90’s Juan Maldacena discovered that the his concept to the audience. Superstring Theory is dual to the N=4 supersymmetric Yang-Mills theory in the sense that a small coupling in one of the theories correspond to a large coupling in the other, and this idea has been dominating fundamental physics since then. Maldacena’s paper is the most cited paper in physics. A few years later Bo Sundborg and later, Edward Witten asked the question what happens when the string parameter goes to infinity discussed above and found dualites between higher spin theories and non-interacting Yang-Mills theories. This created a new venue to use higher-spin theories to study dynamical systems on the dual side. This has been a very fruitful way to use the new knowledge in higher-spin theories.

The Institute of Advanced Studies (IAS) at Nanyang Technological University (NTU) organised the International Workshop on Higher Spin Gauge Theories Prof Anders Bengtsson (University of Borås) delivering his talk from 4 to 6 November 2015 in Singapore. on “Revisiting the light-front: Can the full quartic higher helicity vertex be computed” at the workshop.

There were 20 speakers and about 40 participants from overseas and local who attended the workshop, where all the new developments were discussed. Among the speakers were Mikhail Vasiliev from the Lebedev Institute in Moscow and Bo Sundborg from Stockhom University mentioned earlier. Among the other speakers were Marc Henneaux from Université Libre in Brussels, Rajesh Gopakumar from ICTS-TIFR in Bangalore, Arkady Tseytlin from Imperial College in London, Antal Jevicki from Brown University in Providence, USA, Murat Günaydin from Penn State University, University Park, PA, USA and Soo-Jong Rey, Director at the new Center for Theoretical Physics of the Universe in Daejeon, South Korea and Anders Bengtsson from University of Borås in Sweden. The meeting was a great success and the participants were very pleased with the outcome of the workshop. Prof Mikhail Vasiliev (Lebedev Physical Institute) discussing with the audience during the Q&A session.

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Quantum Physics in Modern Technology by Ngee-Pong Chang City College of New York and Institute of Advanced Studies, NTU

s technology has progressed over the ages, it has When quantum mechanics was born in the 1920’s, the often been the leader for scientific breakthroughs. atomic scale of an Angstrom or so was not within reach ANobody is sure when the telescope was first of technology, so scientists could only infer about atomic invented, and yet with the telescope came the exploration structure by x-ray scattering with wavelengths of an of the night sky, leading to deduction that planetary Angstrom or so. But today, nanotechnology allows the orbits are elliptical by Kepler and the subsequent manipulation of matter with at least one dimension sized breakthrough by Newton on the universal law of from 1 to 100 nanometres. gravitation. Today, the Hubble Space Telescope provides a window into the cosmic big bang. Likewise, with the In electrical and electronic engineering, the technology technology breakthrough in achieving low temperatures today enables scientists to use nanoscale chips to explore of a few Kelvins came the Onnes discovery of one-dimensional quantum mechanical systems, and this superconductivity. With the breakneck speed in low has in turn led to the development of quantum devices temperature technology, physicists are able to explore such as SQUID, ballistic conductors, nanowires and Bose-Einstein condensation and properties of matter in quantum dots. In the same direction, precision technology the nanokelvin temperature range. allowed the measurement of Quantum Hall Effect, and Fractional Quantum Hall Effect.

It was a privilege for me to be invited to give a short intensive course on Quantum Physics in Modern Technology to the PhD graduate students at the School of Electrical and Electronic Engineering School at NTU. The course was conducted from 2 to 5 June 2015, with four hours of lecture on each weekday, lasting the entire 40 hours of a 3 credit academic course. There were 7 enthusiastic graduate students who participated in the course.

While it was a heavy load for the lecturer to prepare and to pontificate in front of these students, it was an even heavier load for the students to sit through it all, day after day. I was very much encouraged by their interest and their perseverance.

As a physicist, with no background in engineering, it was a challenge to present the basics of Quantum Physics to A scanning microscope image of platinum-lace nanoballs. Liposomes aggregate, providing a foamlike template for a these engineering graduate students. But perhaps platinum sheet to grow. because it is a different perspective, it held their attention.

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Prof Ngee-Pong Chang (third from left) and the students of the EE9902 course on Quantum Physics In Modern Technology.

With a judicious mix and emphasis on how discoveries in fundamental science relied so much on the technology available, it was rewarding to start from the Planck era of 1905 and to cover the birth of Quantum Mechanics, and wave-particle duality, and through it to understand the use and properties of the Schrodinger wave function. The topics included Electron Spin, Pauli Exclusion Principle, Fermi gas, Bose gas, Superconductivity, Josephson junction, SQUID, Quantum Hall Effect, Quantum Transmission & Reflections, Spintronics and Quantised Conductance of Landauer Ballistic Conductors. And the course ended, appropriately, with a brief excursion to the distant galaxies with the Big Bang.

It was interesting also to have covered the beautiful experiment of Tonomura on the Aharanov-Bohm effect, how it confirmed that the quantum mechanical electron responds to the vector potential even when the magnetic Quantum Dots field is vanishing.

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Critical Point From Wrong to Right

by Robert P Crease Stony Brook University

The Yang–Mills theory is central to particle physics, but why did something that was once thought to Changing tide A 1954 theory of particle physics has gone from be so wrong prove to be so right? Robert P Crease ridicule to a central tenet. investigates. (Photo credit: Mikkel Juul Jensen/Science Photo Library)

he early 1950s was the start of new period for What fascinates me about the genesis of Yang–Mills physics. The first accelerators to surpass energies theory, though, is how it could go from being wrong to Tof 1 GeV were coming online. No longer would being right – even indispensable – in a mere 20 years. In experimentalists have to climb mountains or set sail in an attempt to get a grip on the answer, and to become hot-air balloons to hunt cosmic rays and strange particles; acquainted with the possibilities of Yang–Mills in post- they could now create and study them conveniently and Standard Model theories, I attended an international copiously in the safety of the laboratory. The experimental conference entitled “60 Years of Yang–Mills Gauge Field workplace in particle physics was suddenly booming, Theories” held in May at the Nanyang Technological which made it a thrilling time for theorists as well. University in Singapore. Attended by Yang himself (Mills died in 1999), the conference made it clear how and why What sense, the theorists wanted to know, did the new Yang–Mills has become such a seminal event in the particles all make? What schemes could be devised to history of physics. organise a particle equivalent of the periodic table? It wasn’t clear which path to take, and a variety of tools The Pauli snag were developed for handling the strong, weak and Yang–Mills theory did not have an auspicious beginning. electromagnetic interactions. Theorists spoke different In 1953 Yang went to Brookhaven National Laboratory mathematical languages, making their workshop a kind for a year, where his officemate was Mills, who was then of Babel. in his last year of getting his PhD at Columbia University. Yang shared with Mills his fascination with the possible Then, in 1954, Chen-Ning “Frank” Yang and Robert Mills connection between symmetries and particle interactions; proposed a mathematical scheme that might be useful for might forces in nature, in other words, arise somehow the strong interaction, which (among other things) binds from the conservation of symmetries? protons and neutrons together in the nucleus. The two theorists – and anyone acquainted with the details of Others had also explored this thought. In 1918, for field theory – knew that the scheme contained a glaring instance, Hermann Weyl had tried to explain defect, which I’ll mention in a moment. But over six electromagnetism as arising from a symmetry of the decades Yang–Mills, as it is known, has become phase of the wave function. Yang and Mills now fundamental not only to the Standard Model of particle wondered if they could find some symmetry among physics – which describes all known particles and forces particles that would dictate their interactions, and found bar gravity – but also to efforts to go beyond it. Yang– a promising-looking candidate called “isotopic spin”, Mills is the loom on which modern particle physics is first described by Werner Heisenberg in 1932. Just as the woven. High-energy physics is unthinkable without it. phase of the wave function in electromagnetism can be

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Years later in his Selected Papers, trying to express their “ High-energy physics is unthinkable rationale for doing so despite the obvious defect, Yang wrote simply: “The idea was beautiful and should be without Yang–Mills.” published.” The paper appeared in October 1954 (Phys. Rev. 96 191). In it, the authors wrestled with the nature of the B field in the final section, which in hisSelected Papers Yang wrote was “more difficult to write than all earlier shifted arbitrarily in space and time because the sections”. In regard to its mass, the authors added, “we interaction with the electromagnetic field cancels out the do not have a satisfactory answer”. Small wonder that effect of the alteration, so Yang and Mills proposed to do their work was initially regarded as merely a mathematical the same for isotopic spin, hypothesising the existence of curiosity. a “B field” to counteract the change. Overcoming the snag In February 1954 Robert Oppenheimer invited Yang to Today, the phrase “Yang–Mills” can be used in two ways: present the work at a seminar at the Institute for to refer (1) to the specific scheme proposed by Yang and Advanced Study (IAS) in Princeton, New Jersey. Mills in 1954, or (2) as shorthand for any non-Abelian Wolfgang Pauli was present. He had been pursuing a gauge theory of the sort that is now fundamental to the similar thought, but had quit after encountering what Standard Model. The Pauli snag had to be overcome for seemed to be a show-stopping issue: in such theories, the (1) to turn into (2). Precisely how this transformation mass of such a field has to be zero. Pauli knew that in happened is a complicated, 20-year saga with unexpected “Abelian” theories, such as quantum electrodynamics twists, dramatic moments, and tangled plots and sub- (QED), it’s alright if the force-carrying particle is zero; plots. For example, in electroweak theory, which unifies this is indeed what lies behind our understanding of the the electromagnetic and weak interactions, spontaneous zero mass of the photon. But extending field theory to symmetry breaking – discovered in the 1960s – was hadrons required a “non-Abelian theory”, in which found to create a loophole around the Pauli snag. Still, nature requires that the force-carrying particles are Yang–Mills theories of the electroweak interaction were massive. not taken seriously until the 1970s, when they were shown to be “renormalisable”, meaning essentially that The cranky perfectionist interrupted Yang’s presentation they were mathematically sound with no unwanted demanding to know the mass of the B field. Yang said he infinities. didn’t know, and resumed the presentation. Pauli cut him off again with the same demand, to which Yang Meanwhile, in the physics of the strong interaction, a responded that he and Mills had reached “no definite Yang–Mills-like theory had long been assumed to be a conclusions”. Pauli snapped back, “That is not sufficient useless tool. In 1968, however, the results of “deep” excuse”, in such a hostile way that Yang, distressed and inelastic electron–proton scattering at the Stanford Linear uncertain, sat down. An awkward silence ensued, with Accelerator Laboratory suggested that quarks, the the seminar effectively at a halt. Oppenheimer then said, constituents of hadrons, were not mere mathematical “We should let Frank proceed.” He did, but with the rest entities but free particles at short distances. This work of the presentation having an awkward flavour in the motivated physicists to take the possibilities of quantum shadow of Pauli’s unanswered, and obviously all- field theory for the strong interaction more seriously, important, question. provided that a version of quantum chromodynamics could be developed in which the coupling gets weaker at Pauli may have been abrupt and inconsiderate, but he short distances. was merely channelling the voice of the quantum field theory of the day, and his question was on the money. After yet more plot twists, such an “asymptotically free” Yang–Mills theory required massless force-carrying field theory was eventually found in 1973. Here the Pauli particles. But nature said that such particles are massive. snag was overcome because while Pauli’s question was This defect meant that the Yang–Mills theory was about things that today we’d call quarks and gluons, obviously wrong. quantum chromodynamics showed that the relevant physical states are actually “colour singlets”. These are When Yang returned to Brookhaven following his IAS pairs or trios of quarks bearing a quantum number called talk, he and Mills decided to publish their work anyway. colour, the combination of which cancels out. A non-

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Abelian gauge theory of the sort Yang and Mills were try world, to which the Yang–Mills proposal itself contributed trying to build turned out to apply to entities different and even made possible. Sometimes, it seems, the world from the neutrons and protons and pions that had has to change before a theory will fit it. inspired their effort. Theory-making is therefore not always a matter of The most remarkable aspect of the tortured transformation seeking something provable and applicable to the world. story of how Yang and Mills went from their original It involves articulating a sense of the world that’s yet to 1954 proposal to an indispensable tool of modern physics take shape. In some cases, therefore, theory-making is – to paraphrase Lochlainn O’Raifeartaigh in his book involves summarising and organising some pre-existing The Dawning of Gauge Theory – not that it took so much sense of the world that is not yet explicitly stated, before time, but that it came together at all. any proof or evidence. (Afterwards, of course, we can say it was this way all along.) The 1954 Yang–Mills theory A new era laid out what would make it possible for the resources of The development had a tremendous impact on high- quantum field theory to apply. It illustrates that some energy theory. In the 1950s theorists were segmented into perfectly respectable theories can be open to being filled different ethnicities, with those who worked on strong, in rather than matching the world in every detail – the weak and electromagnetic interactions each using theory of evolution being another, though rather different tools and speaking different mathematical different, illustration. languages. Just 20 years later, all had changed. Yang– Mills established field theory as the dominant theoretical The critical point language and unified the mathematical Babel. It also had On the last day of the Singapore conference, Da Hsuan longer-term structural effects, kick-starting the era when Feng of the University of Macau asked me an intriguing looking at constraints at low energies let you make question. “Sixty years after Maxwell’s equations,” he predictions at very high energies. Over time the landscape said, “you could easily get the public to appreciate the of high-energy or short-distance physics has been importance and relevance of his work. The same is true dramatically reshaped by Yang–Mills theory and is likely of general relativity and quantum mechanics. But how to remain a key part of future developments. can we get the public to share the same appreciation for Yang–Mills?” Some discoveries not only contribute to science but can also tell us about science, and Yang–Mills is one. How The obvious snappy comeback is that Yang–Mills is just was it possible for a theory to be not yet true of the world? impossibly obscure and arcane. But to non-physicists, so It is impossible to pin down to any specific date between are the other theories that Feng mentioned. Part of the 1954 and, say, 1975 the exact moment when Yang–Mills answer is surely that those theories relate differently to went from a theory that did not apply to the world to one public interests. Maxwell’s theory has many practical that did. It required a gradual shift in ideas about the applications – from mobile phones to radio. General relativity has fewer applications, but a dramatic discovery story and a charismatic discoverer (Einstein). Quantum mechanics has weirdness, as well as a cast of interesting co-discoverers and esoteric devices on the horizon.

Feng’s question left me with the feeling that one of the biggest unsolved challenges of Yang–Mills theory is simply finding ways for outsiders to get a hint, at least, of the stunning achievement it represents.

______Robert P Crease is a professor in the Department of Philosophy, Stony Brook University, US. He is the co- author of The Quantum Moment, e-mail [email protected] Prof Robert Crease delivering his talk on “Yang-Mills for Historians and Philosophers” at the Conference on 60 Years of Yang-Mills Gauge Field Theories, May 2015. This article first appeared inPhysics World October 2015.

JANUARY 2016 | 35 FORTHCOMING EVENTS

17 to 21 January 2016 8th International Science Youth Forum with Nobel Laureates in Singapore Hwa Chong Institution

17 to 22 January 2016 4th Global Young Scientists Summit Organised by National Research Foundation, supported by IAS

18 to 29 January 2016 IAS-ICTP School on Quantum Information Processing Nanyang Executive Centre, NTU

25 to 28 January 2016 Memorial Meeting for Nobel Laureate Professor Abdus Salam’s 90th Birthday Nanyang Executive Centre, NTU

1 to 6 February 2016 Workshop on the Evolution of Cells, Genomes and Proteins Nanyang Executive Centre, NTU

29 February to Conference on New Physics at the Large Hadron Collider 4 March 2016 Nanyang Executive Centre, NTU

21 to 24 March 2016 4th International Workshop on Solar Energy for Sustainability: Photosynthesis and Bioenergetics Nanyang Executive Centre, NTU

23 to 24 May 2016 Workshop on Sustainable Chemistry Nanyang Executive Centre, NTU

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