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Chen Ning Yang

 
Chen Ning Yang
(born Sept. 22, 1922, Hofei, Anhwei, China) Chinese-born U.S. theoretical physicist. He immigrated to the U.S. in 1945 and studied with Edward Teller at the University of Chicago. He showed that parity is violated when elementary particles decay. This and other work in particle physics earned him and Tsung-Dao Lee (b. 1926) a 1957 Nobel Prize. His research focused mostly on interactions involving the weak force among elementary particles. He also worked in statistical mechanics.

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Scientist:

Chen Ning Yang

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Chinese–American physicist (1922–)

Yang, who was born the son of a mathematics professor at Hefei in China, graduated from the National Southwest Associated University in Kunming and received an MSc from Tsinghua. A fellowship enabled him to travel to America, where he studied for his PhD at the University of Chicago, under Enrico Fermi. After teaching at Chicago he joined the Institute for Advanced Study, Princeton, becoming professor of physics in 1955. In 1965 he was appointed Einstein Professor of Physics and director of the Institute of Theoretical Physics at the State University of New York, Stony Brook.

Yang collaborated with Tsung Dao Lee, and in 1956 they made a fundamental theoretical breakthrough in predicting that the law of conservation of parity would break down in the so-called weak interactions. Their startling prediction was quickly confirmed experimentally, by Chien-Shiung Wu, and in 1957 Yang and Lee were awarded the Nobel Prize for physics.

Yang has also made other advances in theoretical physics. In collaboration with R. L. Mills he proposed a non-Abelian gauge theory – also known as the Yang–Mills theory – a mathematical principle describing fundamental interactions for elementary particles and fields. Yang has also made contributions to statistical mechanics.

Biography:

Chen Ning Yang

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The Chinese-born American physicist Chen Ning Yang (born 1922) codiscovered the nonconservation of parity in weak interactions.

Academically inclined from childhood Chen Yang was born September 22, 1922, in Hotei, Anhwei, in China, enjoying what he later categorized as "a tranquil childhood that was unfortunately denied most of the Chinese of my generation." His father was a professor of mathematics at Tsinghua University, where Yang came to do post-graduate study after earning his bachelor's degree in 1942.

In 1944 Yang completed his master's degree, after which he taught in a Chinese high school for a time and then traveled to the United States on a fellowship. Determined to benefit from direct contact with Enrico Fermi (the 1938 Nobel laureate who later built the world's first nuclear reactor), Yang enrolled at the University of Chicago in 1946. He completed his doctoral degree in less than two years, his thesis being supervised by Edward Teller.

Soaring to the Top

Yang remained a year at the University of Chicago as instructor in physics, and in 1949 went to the Institute for Advanced Study in Princeton; in 1955 he became one of the very small number of professors on the institute's permanent staff. In 1950 he married Chih Li Tu, a former student of his in China, who was studying in Princeton. The Yangs had two sons and one daughter.

Although Yang consistently made very significant contributions to statistical mechanics and symmetry principles, he is best known for his and Lee's joint work demonstrating the limitations of the principle of conservation of parity. This principle, although tacitly assumed for centuries to be valid, took on entirely new significance with the birth of relativity, with an empirical rule discovered by O. Laporte in 1924, the advent of quantum mechanics, and E.P. Wigner's 1927 proof that Laporte's rule follows from the "right-left symmetry" of the electromagnetic forces in the atom. Conservation of parity, along with, for example, conservation of energy and momentum, seemed to be a general law of nature. Indeed, its consequences - for example, that the same experiment carried out on an object and its mirror image should yield the same result - seemed to be so obviously true that its universal validity was unquestioned.

Lee and Yang came to feel otherwise in the course of their attempts to understand what was known as the "thetatau puzzle"; two particles, the theta meson and the tau meson, having the same mass and lifetime, would ordinarily have been considered to be one and the same particle, except that while the former decayed into two pions ("even parity"), the latter decayed into three ("odd parity") - and the same particle decaying into two states of different parity would constitute a violation of conservation of parity. Only after intensive study and an extensive survey of the relevant experimental evidence did Lee and Yang conclude in early 1956 that for interactions like the ones described - the so-called "weak interactions," in contrast to the "strong" nuclear interactions, the electromagnetic interactions, and the gravitational interactions - there was absolutely no conclusive experimental basis for conservation of parity. This astonishing fact had escaped all their contemporaries. Indeed, in the words of O.B. Klein, it had been revealed to Lee and Yang only as a consequence of their "consistent and unprejudiced thinking."

But nonconservation of parity in weak interactions was still only a hypothesis. Lee and Yang therefore suggested a number of specific experimental tests for it, all of which yielded positive results. Perhaps the most famous of the tests was the cobalt-60 beta-decay experiment carried out by Madame C.S. Wu of Columbia University and her National Bureau of Standards collaborators. Since Lee and Yang's discovery led to a reexamination of all of the conservation laws, it shook the very foundations of physics, opening up entirely new and unanticipated vistas. For it, they received a number of honors, the highest of which was their shared Nobel Prize for 1957.

A New Life at Stony Brook

In the summer on 1965 Yang was invited, as he often was, to spend a summer worrking at the Brookhaven National Laboratory near the new Stony Brook-based State University of New York. He met many of the physics faculty there, and the following year he was appointed Albert Einstein Professor of Physics and Director of the Institute of Theoretical Physics, which was established especially to attract other top physicists who wished to work with Professor Yang.

By 1997 Yang had been at Stony Brook for 31 years. A man with a strong moral conscience, he had done whatever he could to promote friendship between his adopted home-land and his native China. In 1971 he beecame the first President of the National Association of Chinese Americans, following up with encouragement in every possible quarter to establish the diplomatic relationship between the two countries that finally came to pass in 1979. He also raises an ongoing fund of money, that allows scholars from China to visit the Stony Brook campus for study purposes. Most of them are aware of his many trailblazine papers, which were collected together in a book called Selected Papers 1945-1980, published in 1983 by W.H. Freeman. In honor of Professor Yang's 70th birthday, another volume, Chen Ning Yang: A Great Physicist of the Twentieth Century, was produced by several former students. Obviously, all of them have great respect and affection for him. As many of the pieces in the book note, it is Yang's warmth and sensitivity as much as his reputation which have elevated the Physics Department of the State University of New York to great heights in the world of scientific research.

Further Reading

Yang discussed his and Lee's discovery in his Nobel lecture, reprinted in Nobel Foundation, Nobel Lectures in Physics, vol. 3 (1967). A detailed account of the discovery is also in Jeremy Bernstein, A Comprehensible World (1967).

Additional Sources

Selected Papers 1945-1980 W. H. Freeman, 1983.

Liu, C. S., ed. Chen Ning Yang: A Great Physicist of the Twentieth Century.

 
Columbia Encyclopedia:

Chen-ning Yang

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Yang, Chen-ning (chĕn-nĭng yäng), 1922-, American physicist, b. China, Ph.D. Univ. of Chicago, 1948. Yang was a member of the Institute for Advanced Study at Princeton, N.J. from 1949 to 1955, and a professor of physics there from 1955 to 1965. In 1965 he was appointed Albert Einstein Professor of Physics of the State Univ. of New York at Stony Brook. He is known for his researches in statistical mechanics and particle physics. With American physicist T. D. Lee he shared the 1957 Nobel Prize in Physics for research refuting the law of parity, which stated that, at the subatomic level, nature does not distinguish between left-and right-handed configurations: if a nuclear reaction or decay occurs in nature, then so does its mirror image and with equal frequency.
Wikipedia:

Chen Ning Yang

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This is a Chinese name; the family name is Yang (杨).
Chen-Ning Franklin Yang

Born 1 October 1922 (1922-10-01) (age 87)
Hefei, Anhui, China.
Residence China
Nationality  United States (1964–)
Fields Physics
Institutions Institute for Advanced Study
State University of New York at Stony Brook
Chinese University of Hong Kong
Tsinghua University
University of Chicago
Alma mater National Southwestern Associated University
Tsinghua University
University of Chicago
Doctoral advisor Edward Teller
Known for Parity violation
Yang-Mills theory
Yang-Baxter equation
Notable awards Nobel Prize in Physics (1957)

Rumford Prize (1980)
National Medal of Science (1986)
Benjamin Franklin Medal (1993)

Albert Einstein Medal (1995)

Chen-Ning Franklin Yang (simplified Chinese: 杨振宁traditional Chinese: 楊振寧pinyin: Yáng Zhènníng) (born October 1, 1922)[1] is a Chinese-American physicist who worked on statistical mechanics and particle physics. He, together with Tsung-dao Lee, received the 1957 Nobel prize in physics for their work on parity nonconservation of weak interaction. Yang naturalized as United States citizen in 1964.

Contents

Biography

Yang was born in 1922 in Hefei, Anhui, China, his father Yang Ko-Chuen (simplified Chinese: 杨武之pinyin: Yáng Wǔzhī) (1896–1973) was a mathematician and his mother Luó Mènghuà (罗孟华) was a housewife. Yang attended elementary school and high school in Beijing, and in the autumn of 1937 his family moved to Hefei after Japanese invaded China. In 1938 they moved to Kunming, Yunnan, where the National Southwestern Associated University was located. In the same year, as a second year student, Yang passed the entrance examination and studied at the National Southwestern Associated University. He received his bachelor's degree in 1942, the thesis being about the application of group theory to molecular spectra, under the supervision of Wu Ta-you (吴大猷) (1907–2000). He continued to study graduate courses there for two years under the supervision of Wang Zhuxi (王竹溪) (1911–1983), working on statistical mechanics. In 1944 he received his master's degree was awarded a scholarship known as the Boxer Indemnity (simplified Chinese: 庚子赔款traditional Chinese: 庚子賠款pinyin: Gēngzǐ péikuǎn), a scholarship set up by the United States government using the funds raised from the money China was forced to pay out following the Boxer Rebellion. He was delayed for one year, during which time he taught in a middle school as a teacher and studied field theory.

From 1946, Yang studied at The University of Chicago with Edward Teller (1908–2003), where he received his doctorate in 1948 and remained for a year as assistant to Enrico Fermi. In 1949 he moved to the Institute for Advanced Study where he began a period of fruitful collaboration with Tsung-Dao Lee. In 1966 he moved to the State University of New York at Stony Brook and became the Albert Einstein Professor of Physics and the first director of a newly founded Institute for Theoretical Physics which is now known as C. N. Yang Institute for Theoretical Physics. He retired from Stony Brook in 1999 as Emeritus Professor.

He has been elected a Fellow of the American Physical Society, the Chinese Academy of Sciences (中国科学院, Beijing ), the Academia Sinica (中央研究院, Taiwan), the Russian Academy of Sciences, the Royal Society, etc. and was awarded an honorary doctorate by Princeton University (1958), Moscow State University (1992), Chinese University of Hong Kong (1997), etc.

Yang visited the Chinese mainland in 1971 for the first time after the thaw in China-US relations, and has subsequently made great efforts to help the Chinese physics community to rebuild research atmosphere which was destroyed by the radical political movements during the Great Proletarian Cultural Revolution. After retiring from Stony Brook he returned as honorary director of Tsinghua University, Beijing, where he is the Huang Jibei – Lu Kaiqun professor at the Center for Advanced Study (CASTU).

Yang married Chih-li Tu (traditional Chinese: 杜致禮pinyin: Dù Zhìlǐ), a teacher, in 1950 and has two sons and a daughter: Franklin Jr., Gilbert, and Eulee (in order of age). His father-in-law was the Kuomintang General Du Yuming. His wife died in the winter of 2003. At the age of 82, Yang became engaged to 28-year old Weng Fan (simplified Chinese: 翁帆pinyin: Wēng Fān) who was studying for her master's degree at Guangdong University of Foreign Studies. They married in early 2005. Due to his flaunting "marriage of the century" to a very conservative Chinese society, respect for Yang has deteriorated considerably in China. Currently, he is also facing some emabarrasing scrutiny on his academic integrity, or lack of, based on a new book just published in Beijing. (Check websites and newspapers in Beijing and Shanghai for the month of Dec 2009).

Awards

See also

Notes

  1. ^ Bing-An Li, Yuefan Deng. "Biography of C.N. Yang" (PDF). http://insti.physics.sunysb.edu/~yang/yangbio.pdf. Retrieved 2007-09-11. "His birth date was erroneously recorded as September 22, 1922 in his 1945 passport. He has used this incorrect date on all subsequent official documents." 

References

  • Yang, C.N. (1952) [1952]. Special problems of statistical mechanics. Seattle: University of Washington Press. ASIN B0007FZHH4. 
  • Yang, C.N. (1963) [1961]. Elementary Particles: A Short History of Some Discoveries in Atomic Physics. Princeton: Princeton University Press. ASIN B000E1CBGG. 
  • Yang, C.N. (1983) [1983]. Selected papers 1945-1980, with commentary (Chen Ning Yang). San Francisco: W.H. Freeman. ISBN 071671406X. 
  • "C.N. Yang Institute for Theoretical Physics (YITP)". http://insti.physics.sunysb.edu. Retrieved 2008-01-05. 

External links


 
 
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