Chen Ning Yang

• Born: October 1, 1922
• Place of Birth: Hefei, Anhui Province, China

SCIENTIST

Chen Ning Yang and his colleague Tsung-Dao Lee were jointly awarded the 1957 Nobel Prize in physics. Their work helped overturn a fundamental law of physics known as the Conservation of Parity Law, which held that elementary particle reactions always had right and left symmetry. Yang also partnered with Robert Mills to develop the Yang-Mills theory, which became an important fundamental of quantum physics. His research with Rodney J. Baxter resulted in the Yang-Baxter equation for statistical mechanics. In addition to his work as a scientist, Yang was a strong advocate for improving relations between China and the United States.

Full name: Chen Ning Yang

Birth name: Yáng Zhènníng

Early Life

Chen Ning Yang was born on October 1, 1922 in Hefei, in the province of Anhui, China. Growing up, Yang lived in Peking (now Beijing), where he attended Chung Te Middle School before transferring to the Provincial Middle School in Hefei. The family later moved to Kunming, where Yang attended Kun Hua Middle School. He earned his BS from National Southwest Associated University in 1942 and received his MS from Tsinghua University in 1944. After graduating, Yang conducted research at National Southwest Associated University and taught classes at its affiliated middle school. During his early life, Yang read a biography of Benjamin Franklin that inspired him to later select Franklin as a nickname. Eventually Franklin was shortened to Frank.

In 1945, Tsinghua University awarded Yang a fellowship at the University of Chicago, where he studied particle physics and statistical mechanics. In Chicago, he met his colleague Tsung-Dao Lee. Yang completed his doctoral thesis, “On the Angular Distribution in Nuclear Reactions and Coincidence Measurements,” in 1948, and earned his PhD. During the next year, he taught courses at the University of Chicago. He also spent time in Princeton, New Jersey, where he became affiliated with the Institute for Advanced Study in 1949. On August 26, 1950, Yang married Chih Li Tu. Their son, Franklin, was born in 1951. In 1953, Yang accepted an opportunity to work at the Brookhaven National Laboratory in Upton, New York. It was here that he and R. L. Mills devised the Yang-Mills theory. Yang became a full professor at the Princeton Institute for Advanced Study in 1955.

Life’s Work

In 1956, Yan and Lee published an article “The Question of Parity Conservation in Weak Interactions” in the journal Physical Review. Their work with the subatomic particles known as k-mesons, also called the tau-theta puzzle, had surprising results. Yang and Lee projected that the conservation of parity law was invalid, because the particles did not react according to the law, which assumed that their behavior would be symmetrical.

After publishing their findings and suggesting tests that might be conducted to prove their hypothesis, Yang and Lee had their results verified by other scientists and were subsequently awarded the Nobel Prize in Physics in 1957. In 1958, Yang’s second son, Gilbert, was born. That same year, Yang earned an honorary doctorate from Princeton. His daughter Eulee was born three years later, and after several more years, Yang became a US citizen. Yang taught at the Institute for Advanced Study until 1965. He spent the next summer at Brookhaven National Laboratory and became an Albert Einstein Professor of Physics and Director of the Institute of Theoretical Physics at the State University of New York (SUNY), Stony Brook.

In the 1970s, Yang visited China to promote work in the sciences. He helped establish a program that supported visiting scientists’ research at SUNY. He also participated in the launching of the Foundation for the Center for Advanced Research at Zhongshan University. Yang became the first president of the National Association of Chinese Americans and a member of the Asian Pacific Physical Society. He began serving as Distinguished Professor-at-Large at the Chinese University of Hong Kong in 1986.

After his retirement in 1999, Yang returned to Tsinghua University. He was granted permanent residency in China in 2004, and in 2015 renounced his US citizenship to become a citizen of China once more.

Yang’s first wife died in October 2003, and in 2004 he married his second wife, Weng Fan, a graduate student. The fifty-four-year age difference between the couple made headlines in China when news of their engagement was leaked.

In 2022, Yang's story was told in the documentary Yang Chen Ning--The Most Influential Physicist of Our Time. It was directed by Pierre Lergenmuller, Guillaume Tisserant, and Yiqian Zhang; Zhang also wrote it.

Significance

As attested by his many awards, honors, and prizes, and his multiple research articles, Yang’s contributions to physics are many and varied. Yang’s expertise has been applied in the fields of particle physics, nuclear physics, and theoretical physics. In addition to the Nobel Prize he shared with Lee, his public recognitions have included the Liberty Award (1986), the National Medal of Science (1986), the Oskar Klein Memorial Lecture and Medal (1988), the Benjamin Franklin Medal (1993), the Lars Onsager Prize (1999), and the King Faisal International Prize (2001).

Yang’s articles have been published in many science journals, including theBulletin of the American Mathematical Society, Physical Review, theReview of Modern Physics, and theChinese Journal of Physics. Yang has also served as a member of the Board of Trustees at the Woods Hole Oceanographic Institute, the Salk Institute for Biological Studies, the Stony Brook Foundation, and Rockefeller University. He has also served on the Board of Directors for the Neuroscience Institute and for Scientific American, Inc. After regaining Chinese citizenship, he became a member of the Chinese Academy of Sciences, China's highest scientific research organization. The Chen Nin Yang–Wei Deng Endowed Chair in Physics and Astronomy at Stony Brook University, created in 2017, was named in his honor.

Bibliography

Cheng, Yangyang. "For Science, or the 'Motherland'? The Dilemma Facing China's Brightest Minds." The China Project, 30 Jan. 2019, thechinaproject.com/2019/01/30/for-science-or-the-motherland-chinas-brightest-minds/. Accessed 21 Aug. 2024.

"Chen Ning Yang—Facts." Nobelprize.org, 2014, www.nobelprize.org/nobel‗prizes/physics/laureates/1957/yang-facts.html. Accessed 3 May 2018.

Lautz, Terry. "Chen-Ning Yang: Science and Patriotism." In Americans in China, Oxford UP, 2022, pp. 90-111, doi.org/10.1093/oso/9780197512838.003.0005. Accessed 21 Aug. 2024.

Wu, Fa Yueh. “Professor C. N. Yang and Statistical Mechanics.” Exactly Solved Models: A Journey in Statistics Mechanics (Selected Papers with Commentaries (1963–2008). Print. London: World Scientific, 2009.

Yang, Chen Ning. Elementary Particles: A Short History of Some Discoveries in Atomic Physics. Princeton, NJ: Princeton UP, 1962. Print.

Yang, Chen Ning. Selected Papers 1945–80. London: World Scientific, 2005. Print.

Zhang, Zhihao. "Nobel Laureate, Turing Award Winner Become Chinese Citizens, Join CAS." ChinaDaily, 21 Feb. 2017, www.chinadaily.com.cn/china/2017-02/21/content‗28287654.htm. Accessed 3 May 2018.