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YANG Chen Ning




YANG Chen Ning

Doctor of Science
honoris causa

Mr Pro-Chancellor,

Professor YANG Chen Ning celebrated his centennial birth last year. We gather here today to honour a remarkable career that has spanned nearly eight decades across two continents, with its impact felt by several generations of aspiring young scientists and intellectuals in Chinese-speaking communities and beyond. A modern master of physics with significant contributions to elementary particle physics, statistical mechanics and condensed matter physics, Professor Yang’s work has further transcended the boundaries of physics. He is a beloved living legend, an eloquent spokesperson for global higher education, and a true icon of our time.

Professor Yang’s scientific journey began in wartime China when he was a science major at the  National Southwestern Associated University (Xinan Lianda or Lianda). A cluster of prestigious universities from the North displaced because of the war, Lianda was a shining beacon of higher learning and cutting-edge research built on a makeshift campus in a remote region of a war-ravaged country. Yang received his BSc from Lianda in 1942 and an MSc from Tsinghua University in 1944 and would later credit this foundational work as the source of everything. If first-rate young researchers could be fostered in the midst of a long and devastating war and in such a harsh environment, what can we not accomplish in today’s world of abundance, connectivity, and advancement? Throughout his career, and amid all of his acclaim and successes, Yang has never lost sight of his intellectual beginnings. That beacon of light never fades in his brand of idealism; it has consistently illuminated his path, as well as those of many others.

Professor Yang went on to receive a PhD from the University of Chicago in 1948. He joined the Institute of Advanced Study in Princeton in 1949, became a permanent member there in 1952, and was promoted to a Full Professorship in 1955, at the young age of 33. The Nobel Prize in Physics in 1957 was one for a special record book. He won it together with Professor LEE Tsung Dao for the discovery of non-conservation of parity in weak interactions. Yang and Lee were the first Chinese to be awarded the Nobel Prize. A landmark discovery in modern physics, their work furthered our understanding of the structure of matter at the smallest scales.

Symmetry has long been a keyword in Professor Yang’s conceptual framework. While he destroyed parity conservation, he also established the non-Abelian gauge field theory. His collaboration with Robert Mills gave rise to what is known as the Yang-Mills theory, a bold breakthrough that has reshaped physics and modern geometry in the latter half of the twentieth century. To many physicists, Yang’s gauge field theory has an even bigger impact than his Nobel discovery. The Franklin Institute presented the 1994 Bower Award and Prize for Achievement in Science to Professor Yang and highlighted Yang’s gauge field theory in their citation: “This theoretical model, already ranked alongside the works of Newton, Maxwell, and Einstein, will surely have a comparable influence on future generations.” Other distinguished physicists of our time such as Freeman Dyson and Samuel C. C. Ting have also ranked Yang as the preeminent architect of modern physics after Albert Einstein and Paul A. M. Dirac.

In 1966, Professor Yang joined Stony Brook University as Albert Einstein Professor of Physics and the first Director of the Institute for Theoretical Physics, known today as the CN Yang Institute for Theoretical Physics. At the present, he is Emeritus Professor of Stony Brook University, Distinguished Professor-at-large of the Chinese University of Hong Kong, and Professor of Tsinghua University. His mile-long list of accolades include memberships of the US National Academy of Sciences and the Chinese Academy of Sciences, the US National Medal of Science, and honorary degrees from over 20 universities worldwide.

If symmetry is a keyword in Professor Yang’s conceptual framework, style and stylistic analysis are repeatedly evoked in his numerous scientific writings that are read by a diverse readership. In 1983 he famously wrote this: “In every field of creativity, it is one’s taste, together with ability, temperament, and opportunity, that determines one’s style and through it one’s contribution.” It is poignant moments like this that we see Professor Yang as more than a great scientific mind; he is, in fact, a humanist at heart.

Two thick volumes titled Selected Papers of Chen Ning Yang stand as classics in scientific writings. In the preface to the first volume published in 1983, Professor Yang cites the eminent nineth-century Chinese poet Du Fu’s famous lines “文章千古事/得失寸心知,” which he has rendered as “A piece of literature/Is meant for the millennium/But its ups and downs are known/Already in the author’s heart.” There is a poet, a philosopher, and an aestheticist behind Yang Chen Ning the great scientist.

Yang’s friend and fellow physicist Freeman Dyson loved the first volume of Selected Papers. To Dyson, “(Yang) was trying to show us in five hundred pages the spirit of a great scientist, and he magnificently succeeded.” Dyson was struck by how Yang “cherished the past and demolished as little as possible” and how he “cherished with equal reverence the great intellectual tradition of Western science and the great cultural tradition of his ancestors in China.” In calling Yang “a conversative revolutionary,” Dyson then highlighted Yang’s unique quality as a synthesizer, a unifier, and a bridge builder, someone who consistently negotiates between various cultures, between different moments in history, between different scientific schools, between different belief systems, and between sciences and the humanities.

A second volume of Selected Papers of Chen Ning Yang was published in 2013, which collected Yang’s more recent writings, many of which fuse scientific discussions with philosophical reflections. I am particularly drawn to an essay titled “Werner Heisenberg,” which was Yang’s tribute to modern physics’ famed forerunner. In this piece, Yang writes like a poet, depicting, in vivid terms, the heated scientific debates in the interwar years where Heisenberg shared the same stage with other physics giants of the time such as Wolfgang Pauli, Enrico Fermi, and Paul A. M. Dirac. Yang’s scientific papers supplemented by his insightful commentaries serve to contextualise scientific debates in larger social, cultural, and political debates of our time. Containing a remarkable personal as well as professional chronicle, these writings are gems.

Poetry is never far from Professor Yang’s scientific meditations. Also in the Heisenberg piece, Yang ascribes each of the physics giants a poetic quality that is drawn from his reading of classical Chinese poetry. Pauli to Yang stands for “power,” Fermi for “solidarity and strength,” Heisenberg for “deep insight,” and Dirac is for “cartesian purity.” We can see that it is Yang himself who combines all these qualities, power and strength balanced with sensitivity and inward thinking. In his scientific journey as well as his life-long career as an inspirational leader, Professor Yang has consistently practiced this exquisite word—symmetry.

Mr Pro-Chancellor, it is my great honour and tremendous privilege to present to you Professor YANG Chen Ning, for the award of Doctor of Science honoris causa.

Citation written and delivered by Professor Nicole Huang, Public Orator, the University of Hong Kong.

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