Academic achievements Yang has worked on statistical mechanics, condensed matter theory, particle physics and gauge theory/quantum field theory. At the University of Chicago, Yang first spent twenty months working in an accelerator lab, but he later found he was not as good as an experimentalist and switched back to theory. His doctoral thesis was about angular distribution in nuclear reactions. Later he worked on particle phenomenology; a well-known work was the Fermi–Yang model treating pion meson as a bound nucleon–anti-nucleon pair. In 1956, he and Tsung Dao (T.D.) Lee proposed that in the weak interaction the parity symmetry was not conserved, Chien-shiung Wu's team at the National Bureau of Standards in Washington experimentally verified the theory. Yang and Lee received the 1957 Nobel Prize in Physics for their parity violation theory, which brought revolutionary change to the field of particle physics. Yang has also worked on neutrino theory with Tsung Dao (T.D.) Lee, 1957, 1959, CT nonconservation (with Tsung Dao (T.D.) Lee and R. Oheme, 1957), electromagnetic interaction of vector mesons (with Tsung Dao (T.D.) Lee, 1962), CP nonconservation (with Wu Tai-Tsun, 1964). Yang is also well known for his collaboration with Robert Mills in developing non-abelian gauge theory, widely known as the Yang–Mills theory. Subsequently, in the last three decades, many other prominent scientists have developed key breakthroughs to what is now known as gauge theory. In the 1970s Yang worked on the topological properties of gauge theory, collaborating with Wu Tai-Tsun to elucidate the Wu–Yang monopole. Unlike the Dirac monopole, it has no singular Dirac string. The Yang-Mills theory set the template for the Standard Model and modern physics in general, as well as the work towards a Grand Unified Theory; it was called by The Scientist, "the foundation for current understanding of how subatomic particles interact, a contribution which has restructured modern physics and mathematics." The idea was generally conceived by Yang, and the novice scientist Mills assisted him in this endeavor as Mills said,"During the academic year 1953-1954, Yang was a visitor to Brookhaven National Laboratory...I was at Brookhaven also...and was assigned to the same office as Yang. Yang, who has demonstrated on a number of occasions his generosity to physicists beginning their careers, told me about his idea of generalizing gauge invariance and we discussed it at some length...I was able to contribute something to the discussions, especially with regard to the quantization procedures, and