Chen Ning Yang, a world-renowned and Nobel Prize-winning scientist who made revolutionary contributions to our understanding of the laws of physics and the nature of particles, died Oct. 18 in Beijing at age 103.<\/p>\n
After earning his Ph.D. from the University of Chicago in 1948, Yang embarked upon a pioneering research career in which he made numerous field-defining discoveries. He is best remembered for his groundbreaking Yang-Mills theory, which explained the behavior of elementary particles; and his landmark paper on the symmetry of parity laws with UChicago alum Tsung-Dao Lee, PhD\u201950\u2014a discovery that earned them the Nobel Prize in Physics<\/a> in 1957.<\/p>\n Since the late 1990s Yang had served as a professor at Tsinghua University, which in announcing Yang\u2019s passing<\/a>, called him \u201cone of the greatest physicists of the 20th century.\u201d In recent decades he maintained his links with UChicago, engaging with scholars and students at the University\u2019s Center in Beijing. Revered by scientists around the world, Yang had deep impact on fields including particle physics, quantum field theory, and statistical and condensed matter physics.\u00a0<\/p>\n \u201cYang\u2019s pioneering work in theoretical physics revolutionized our understanding of nature\u2019s fundamental laws and laid the groundwork for the Standard Model of particle physics,\u201d said Ka Yee C. Lee, the interim dean of the Physical Sciences Division and the David Lee Shillinglaw Distinguished Service Professor at UChicago. \u201cWe are honored that the University of Chicago played a part in his enduring legacy.\u201d<\/p>\n Physics, brick by brick<\/p>\n Born Sept. 22, 1922 in Hofei, China, Yang grew up near the campus of Tsinghua University, where his father was a professor of mathematics. In January 1946, Yang came to UChicago, drawn to its active research atmosphere and the opportunity to learn from eminent scientists, including Enrico Fermi. Yang told the New Yorker in 1962<\/a> that Fermi taught him \u201cthat physics should not be a specialist\u2019s subject; physics is to be built from the ground up, brick by brick, layer by layer. We learned that abstractions come\u00a0after\u00a0detailed foundation work, not before.\u201d<\/p>\n Yang first worked at UChicago on an accelerator in the lab of Prof. Samuel Allison, but quickly realized his future was not in experimental physics. \u201cI was clumsy in the laboratory, and all my fellow graduate students laughed at me,\u201d Yang told the Simons Foundation<\/a> in 2011,\u201d but they liked me as a person, especially because I could solve theoretical problems.\u201d<\/p>\n Prof. Edward Teller encouraged Yang to turn one of his promising research ideas into a Ph.D. dissertation, which explored the concepts of symmetry and natural phenomenon. \u201cThat became one of the main themes, or perhaps the\u00a0main theme of my subsequent work,\u201d Yang said.<\/p>\n Examining symmetry in nature<\/p>\n Yang served for a year as an instructor at UChicago before joining the Institute for Advanced Study at Princeton, where he worked alongside Robert Oppenheimer. In 1954, Yang worked with Robert Mills to develop the Yang-Mills theory<\/a>, which describes the behavior of elementary particles and is the basis of our understanding of the Standard Model of particle physics.\u00a0<\/p>\n Two years later Yang collaborated with fellow UChicago alum Lee, PhD 1950, on landmark research<\/a> that would revolutionize the field of physics. Exploring long-held assumptions that the laws of physics were the same in a mirror image as in reality\u2014and that all forces conserved parity\u2014Yang and Lee proposed that parity might not hold for interactions with weak forces. A team led by\u00a0Chien-Shiung Wu\u00a0of Columbia University confirmed Lee and Yang’s theory, observing that the decay of cobalt-60 did not happen in the exact same way as its mirror image\u2014and that the left-right symmetry law was violated by the weak interaction.<\/p>\n For their breakthrough, Yang and Lee shared the 1957 Nobel Prize in Physics for their research on parity laws, which the Foundation wrote \u201cled to important discoveries regarding the elementary particles.\u201d\u00a0<\/p>\n \u201cThrough your consistent and unprejudiced thinking,\u201d said one official at the Nobel Prize award ceremony<\/a>, \u201cyou have been able to break a most puzzling deadlock in the field of elementary particle physics where now experimental and theoretical work is pouring forth as the result of your brilliant achievement.\u201d<\/p>\n