To See a World in a Grain of Sand ── The Scientific Life of Shoucheng Zhang Preface Our friend and colleague, Prof. Shoucheng Zhang, passed away in 2018, which was a great loss for the entire physics community. For all of us who knew Shoucheng, it is difficult to overcome the sadness and shock of his early departure. However, we are very fortunate that Shoucheng has left us such a rich legacy and so many memories in his 55 years of life as a valuable friend, a world-leading physicist, a remarkable advisor, and a great thinker. We hope this small exhibition will provide some snapshots of Shoucheng’s wonderful scientific life. ---Biao Lian, Chao-Xing Liu, Xiaoqi Sun, Steven Kivelson, Eugene Demler and Xiao-Liang Qi Shoucheng Zhang A brief history 1963 - 2018 1963 • Shoucheng was born in Shanghai, China to Manfan Ding and Hongfan Zhang 1978 • Admitted to Fudan University 1980 • Began studying at Free University of Berlin 1983 • Graduated from Free University of Berlin • Started Ph.D. at Stony Brook University 1986 • Started working on condensed matter physics 1987 • Received Ph.D. and started postdoc at ITP, UC Santa Barbara • Married his childhood sweetheart, Barbara Yu • Chern-Simons theory of fractional quantum Hall states 1989 • Started at IBM Almaden Research Center, San Jose • Global phase diagram of fractional quantum Hall states 1993 • Joined the faculty of Stanford University • Shoucheng’s son Brian was born 1996 • Shoucheng’s daughter Stephanie was born 1997 • Proposed the SO(5) theory of high Tc superconductors 2001 • Generalized quantum Hall effect to 4 dimensions 2003 • Proposed the intrinsic spin Hall effect 2004 • Early models of quantum spin Hall effect (2004- 2005 2005) 2006 • Predicted the quantum spin Hall effect in HgTe 2007 • Quantum spin Hall effect realized in HgTe Honors and Awards 2008 • Topological magneto-electric effect • Fellow, American Physical Society (2005) 2009 • Prediction and realization of Bi2Te3 family of topological insulators • Guggenheim Fellow (2007) • Prediction of new topological superconductors • Alexander von Humboldt Research Prize (2009) 2010 • Prediction of quantum anomalous Hall effect • Europhysics Prize (2010) 2013 • Quantum anomalous Hall effect realized • Fellow, American Academy of Arts and • Founded venture capital firm DHVC Sciences (2011) • Oliver Buckley Prize (2012) • Celebrated 50th birthday with his friends, • Dirac Medal (2012) current and past group members. • Physics Frontier Prize (2013) 2017 • Experimental evidence of chiral topological superconductor reported • Foreign Member, Chinese Academy of Sciences (2013) 2018 • Founded the Stanford Center for Topological Quantum Physics • Benjamin Franklin Medal (2015) • Passed away on December 1, 2018 • Member, National Academy of Sciences (2015) Early Experience Childhood and School Age Upon observing the equations on the tombstones of Max Planck, Otto Hahn, and Max Born, Shoucheng wrote that Shoucheng Zhang (张首晟) was born in he would “spend my energy on the pursuit of science, 1963 in Shanghai, China. In his hoping that I too would leave behind a life’s work that childhood, Shoucheng already showed could be summed up in a simple equation.” exceptional talent and a strong interest in various fields of knowledge. In the Ph.D. at Stony Brook University attic of Shoucheng’s home there were many books on art, history, philosophy, Shoucheng began his Ph.D. and science left by his grandfather and studies on supergravity at others of his parent’s generation. These Shoucheng at the State University of New included books on the philosophy of age 2 York at Stony Brook in 1983, Russell and Kant and the art of da Vinci and Rodin. advised by Peter van Shoucheng’s favorite activity after school was to read Nieuwenhuizen. In the final books in the attic. In an era when educational resources year of Shoucheng’s Ph.D. were scarce, these books opened a new world to him. In Shoucheng with his advisor (1986-1987), following Prof. Peter van Nieuwenhuizen 1976, Shoucheng’s father bought Shoucheng a set of high Chen-Ning Yang’s suggestion, (middle) and his future wife he started shifting his school textbooks on mathematics, physics, and chemistry. Barbara (left) at their He was immediately attracted by the amazing beauty of graduation ceremony, 1987 science. research direction to College times in Shanghai and Berlin condensed matter physics. He began a collaboration with Steven Kivelson, a In 1977, the National Higher faculty member at Stony Education Entrance Exam of Brook who later became China was restarted after the Barbara, Shoucheng, Chen- Shoucheng’s colleague and end of the Cultural Ning Yang, and Shoucheng’s lifelong friend at Stanford. Revolution. Without father Hongfan, 1987 attending high school, Santa Barbara, IBM and Stanford Shoucheng took the first exam and got admitted to After receiving his Ph.D. in 1987 the Physics Department of Shoucheng (third from the from Stony Brook, Shoucheng Fudan University in Shanghai right in the second row) and became a postdoctoral fellow at in 1978. At the age of 15, he his roommates at Fudan the Institute of Theoretical was the youngest student in University, 1978 Physics (ITP) in UC Santa his class. One year later, in Barbara. In 1987, he married his recognition of his excellent academic performance, childhood sweetheart Barbara Shoucheng and J. Robert Shoucheng was selected for an exchange program to study Yu. He then joined IBM Almaden Schrieffer at Santa Barbara, abroad at the Free University of Berlin, where he received Research Center as a Research 1989 his Diplom-Physiker (Bachelor of Science degree) in 1983. Staff Member from 1989 to 1993. Thereafter, he joined the During his college time in faculty of Stanford University, which remained his academic Germany, besides studying home for the rest of his life. physics, Shoucheng also had During the early years of his rich exposure to German career, Shoucheng focused culture. On a trip back from primarily on the theory of Bonn to Berlin in 1981, he and fractional quantum Hall some friends visited the states and high temperature Stadtfriedhof cemetery in superconductivity. His Shoucheng in front of the Göttingen that houses the scientific achievements in grave of nuclear physicist different areas of physics Otto Hahn in Göttingen, 1981 graves of many scientists. Even A group photo of Shoucheng and after many years, Shoucheng his students after a class at will be overviewed in the often remembered this visit as a source of inspiration. Stanford in 1994 following pages. Fractional Quantum Hall Effect The Fractional Quantum Hall Effect The key idea of this theory is flux attachment, which When Shoucheng began to study condensed matter is achieved by introducing physics in the late 1980s, one of the first topics he became a gauge field with a interested in was the fractional quantum Hall effect Chern-Simons term. The (FQHE). dynamics of this gauge field attaches 2푘 − 1 magnetic fluxes to each The FQHE, experimentally discovered in 1982 by D. C. Tsui, Shoucheng with James H. electron, which H. L. Stormer, and A. C. Gossard, is a remarkable quantum Simons (middle), one of the phenomenon of two dimensional (2D) metals near the founders of Chern-Simons transmutes them into absolute zero of temperature in a strong magnetic field 퐵, theory, and Edward Witten bosons. The FQHE is then where the Hall resistance 푅 is quantized at values (right) at Stanford in 2010. interpreted as the 푥푦 condensate of this boson. ℎ In an interview with Stanford News after Shoucheng’s 푅 = 푥푦 휈푒2 death, Steven Kivelson described this discovery: “One day Shoucheng came to visit and he said, ‘Look what I figured Here 휈 is one of a particular set of rational fractions, ℎ is out.’ He then sketched Planck’s constant, and 푒 is the electron charge. out a basic idea of the theory and all of these mysterious features of the fractional quantum Hall effect just dropped in your lap incredibly simply,” Kivelson said. “That’s not how physics usually works. You usually Shoucheng with Per Bak, slave away at things. But The experiment of Hall Steven Kivelson, and Steven’s The FQHE with 푅 = ℎ/휈푒2, from resistance 푅 = 푉/퐼, from 푥푦 on that day Shoucheng’s wife Pamela Davis at Stony 푥푦 Eisenstein, Stormer, Science 1990 Kosmos 1986 idea was just so focused Brook in 1987, celebrating and so perfect.” Shoucheng’s thesis defense The understanding of the FQHE fundamentally challenged Global phase diagram conventional condensed matter theory. In 1983, Robert B. Laughlin proposed the Laughlin wavefunction which Along the same direction, in 1992 Shoucheng successfully described the ground state of fractional 1 collaborated with Steven Kivelson and Dung-Hai Lee to quantum Hall fluids with 휈 = (푘 = 1,2, ⋯); this laid 2푘−1 propose a global phase diagram of the FQHE, which the foundation for the theory of the FQHE. derived a set of interrelations among various FQHE states. The Chern-Simons Chern-Simons Ginzburg-Landau Theory effective theory and the global phase diagram also Shoucheng was interested in looking for a quantum field revealed the relation theory (QFT) for the FQHE. The presence of the between fractional background magnetic field 퐵 implies that this field theory quantum Hall physics must be quite different from those that were familiar in and various forms of high energy physics. The field theory needed to capture particle-vortex essential features of the FQH state such as the quantized Global phase diagram of FQHE, from S. duality, which still Hall conductance, fractional charged excitations, etc. Kivelson, D.-H. Lee, and S. C. Zhang remains an active Phys. Rev. B 46, 2223 (1992) research topic after In 1989, Shoucheng and his collaborators Thors Hans 30 years. Hansson and Steven Kivelson, proposed the Chern- Simons-Landau-Ginzburg field theory of the FQHE: References S.