22 September 1922 - Birth of Chen Ning Yang, winner of the Nobel Prize in Physics for his theories on parity violation in weak interactions

Chen Ning Yang, also known by his English name Frank Yang, was born in Hefei, China, on 1 September 1922.

Yang began his studies in physics in 1938 at the Southwest China Associated University. He then received a scholarship to the University of Chicago, where he completed his doctorate in 1948. During the following year, he taught physics at the same university and worked as an assistant to Enrico Fermi, the Italian physicist who became famous after creating the first nuclear chain reaction with the Chicago Pile-1 reactor.

In 1949 he was invited to carry out research at the Institute for Advanced Study at Princeton, where he published his work "Elementary Particles and Weak Interactions", a book that compiled much of the knowledge in particle physics that had been available up to that time. In 1952 he became a permanent member of the Institute and, in 1955, a full professor.

Yang's contributions to physics were numerous and very important, especially in the fields of statistical mechanics, particle physics, quantum field theory, and condensed matter physics.

Together with his colleague Lee Tsung Dao, Yang showed experimentally that one of the basic laws of quantum mechanics, called parity conservation, is broken in so-called weak nuclear reactions, nuclear processes that occur, for example, in the emission of beta or alpha particles. In recognition of this achievement, Yang and Lee shared the 1957 Nobel Prize in Physics.

Yang is also recognized for his collaboration with the American physicist Robert Mills, with whom he developed a new type of non-abelian gauge theory, the Yang-Mills theory. These theories eventually formed the basis of the Standard Model and modern particle physics.

In 1965 he was appointed Albert Einstein Professor of Physics at the State University of New York at Stony Brook.

In 1999 he retired from Stony Brook University as professor emeritus to return to Tsinghua University in Beijing as honorary director.

In addition to the Nobel Prize in Physics in 1957, he received other awards such as the National Medal of Science in 1986, the Benjamin Franklin Medal of the American Philosophical Society in 1993, and the Albert Einstein Medal in 1995.