Chen Ning Franklin YANG (楊振寧 pinyin: Yáng Zhènníng) (born September 22, 1922) is a Chinese American physicist, who worked on statistical mechanics and symmetry principles. He received the Nobel Prize in Physics in 1957 at the age of 35, with Tsung-Dao Lee, for a theory in which, to the surprise of theoretical physicists, the weak force between elementary particles did not have parity (mirror-reflection) symmetry. The theory was experimentally verified by Chien-Shiung Wu. Yang is also well known for his collaboration with Robert Mills in developing a gauge theory of a new class. Such "Yang-Mills theories" are now a fundamental part of the Standard Model of particle physics.
Born in Hefei, Anhui, China Yang attended elementary school in Beijing and middle school first in Beijing, then in Kunming.
He received his Bachelor of Science degree from National Southwest Associated University (西南聯合大學) in Kunming in 1942. Two years later, he studied for his Master of Science degree with a full scholarship at Tsinghua University, at the time also in Kunming. He attended University of Chicago on a Tsinghua University Fellowship in January 1946. There he studied for his Ph.D. with Edward Teller and after receiving it in 1948, remained for a year as an assistant to Enrico Fermi. In 1949 he moved to the Institute for Advanced Study and in 1965 to Stony Brook University.
He has been elected a Fellow of the American Physical Society and the Academia Sinica, and was awarded an honorary doctorate by Princeton University (1958).
Yang married Chih-li Tu (杜致禮 Dù Zhìlǐ), a teacher, in 1950 and has two sons and a daughter: Franklin Jr., Gilbert, and Eulee (in order of age).
He retired from Stony Brook University in 1999 and returned to Tsinghua University. His wife died in the winter of 2003. At the age of 82, Yang became engaged to 28-year old Weng Fan, is studying for a masters at Guangdong University, and expects to marry her in early 2005.