Chien-Shiung Wu

Chien-Shiung Wu was born on May 31, 1912, in Liu He, a small town near Shanghai. Her father, Zhong-Yi WuZhong-Yi WuZhong-Yi Wu (1888–1959) was a Chinese school founder who studied at the Nanyang Public School in Shanghai, took part in the political activities around the 1911 revolution and in 1913 founded and headed the Ming De School for girls in Liuhe, Taicang, Jiangsu. He was the father of the physicist Chien-Shiung Wu.Open the full entry, was an engineer by training who took part in the political activities of 1909–1912 that led to the founding of the Republic of China; her mother was Funhua FanFunhua FanFunhua Fan (died 1962) was a teacher in China and the mother of the physicist Chien-Shiung Wu. She visited families to persuade them to send their daughters to the Ming De School founded by her husband, Zhong-Yi Wu.Open the full entry. She had an older and a younger brother. An article in China Science Daily states that her father had been educated at the Nanyang Public School in Shanghai. The National Women’s History Museum’s biography states that her mother was a teacher. An article in the magazine Mathematical Culture gives the name of her older brother as Wu Jianying and those of two younger brothers as Wu Jianhao and Wu Jianjie, the youngest, who died young.⁠[1][2][3][4]

Her grandfather Yi-Feng WuYi-Feng WuYi-Feng Wu was the father of the school founder Zhong-Yi Wu and the grandfather of the physicist Chien-Shiung Wu.Open the full entry, a junior scholar in the national civil service examination system, was at first more interested in his male heirs but later supported her curiosity.⁠[1]

She first attended the Ming De School, which her father had founded and headed and which was one of the first schools in China to admit girls.⁠[1]

The Atomic Heritage Foundation’s timeline gives her birthplace as Taicang, Jiangsu; BritannicaEncyclopædia BritannicaEncyclopædia Britannica is a general English-language encyclopedia first published in Edinburgh, Scotland, in 1768; the name also refers to its publisher, Chicago-based Encyclopædia Britannica, Inc. (which presents itself as The Britannica Group). The print edition ended in 2012, and the company’s main businesses since then have been the online encyclopedia Britannica.com, digital education products for schools and libraries, and Merriam-Webster dictionaries.Open the full entry’s article gives the date of birth as May 29, 1912, and the place as Liuhe, Jiangsu province. An article by Zhang Chengning on the website of the Nanjing University Archives states that the visa file she completed at the U.S.United StatesThe United States is a federal country in North America made up of 50 states, the District of Columbia as the seat of government, and territories such as Puerto Rico and Guam; its capital is Washington, D.C. The Continental Congress adopted the Declaration of Independence on July 4, 1776. The 2020 census (April 1, 2020) counted a resident population of 331,449,281, and the 435 seats of the House of Representatives are apportioned among the states on the basis of the census.Open the full entry consulate general in Shanghai in 1936 likewise gives her date of birth, by the Western calendar, as May 29, 1912, and her birthplace as Liuhe, China; the article calls May 31, 1912, the widely accepted official date and holds that, as 1912 fell in China’s transition from the traditional lunar calendar to the Western calendar, some discrepancy in recording the date is understandable.⁠[5][6][7]

In 1923 she transferred to the Normal School program of the Soochow School for Girls, graduating in 1929, and then spent a year at the Shanghai Gong Xue (Public School). An article in China Science Daily states that she repeatedly named her father and her teacher Hu Shi as the two people who had influenced her most; an article in the magazine Mathematical Culture states that Hu Shi spoke of her as his student at that school, Zhongguo Gongxue.⁠[1][2][4]

In 1930 she enrolled at the school in Nanjing later known as National Central University, switched from mathematics to physics in her second year and graduated with a B.S. at the top of her class in 1934.⁠[1]

A commemorative article in The Paper and the Atomic Heritage Foundation’s timeline date her admission to the university to 1929.⁠[8][5]

After graduating she taught for a year at National Chekiang (Zhejiang) University in Hangzhou, and in 1935–1936 she carried out her first research, in X-ray crystallography, at the Academia Sinica under Jing-Wei GuJing-Wei GuJing-Wei Gu (1900–1983) was a Chinese physicist and physics educator who received a Ph.D. in physics from the University of Michigan in 1931 and is described by Chinese historians of science and newspapers as the first Chinese woman to earn a doctorate in physics. She taught at Nankai University, Datong University in Shanghai, Guangxi University and the Beijing Steel and Iron Institute, and from 1933 to 1937 was also a research fellow of the Institute of Physics of the Academia Sinica, where she mentored Chien-Shiung Wu.Open the full entry. An article carried by ScienceNet states that Jing-Wei Gu, who received her doctorate from the University of MichiganUniversity of MichiganThe University of Michigan is a university founded in Detroit in 1817 that moved to Ann Arbor, Michigan, in 1837; it is governed by a statewide-elected Board of Regents and also has campuses in Dearborn and Flint.Open the full entry in 1931, was the only woman research fellow of the Academia Sinica’s Institute of Physics, where Chien-Shiung Wu served as an assistant. The education entry of her 1936 visa file, as translated in Zhang Chengning’s article on the website of the Nanjing University Archives, states that the subject she taught at National Chekiang University was chemistry and that during the preceding year she had done research at the Academia Sinica in Shanghai.⁠[1][9][7]

Jing-Wei Gu encouraged her to continue her studies in the United States.⁠[10]

In 1936 she traveled by ship to San Francisco with money provided by an uncle; the National Park Service’s profile considers it likely that she was processed at the Angel Island Immigration Station. An article in the magazine Mathematical Culture states that the uncle who offered to pay her tuition and living expenses was Wu ZhuozhiWu ZhuozhiWu Zhuozhi (1897–1967) was a Chinese mechanical engineer and bus-company operator who studied and worked in France and in 1931 founded Jiangnan Qiche Gongsi, a motor bus company in Nanjing that later developed into the city’s public transport enterprise. He was a younger brother of Zhong-Yi Wu and gave financial support to his niece, the physicist Chien-Shiung Wu, when she went to study in the United States in 1936.Open the full entry, who ran his own company. The Jinling Dang’an article on Wu Zhuozhi states that he founded the Jiangnan Motor Company, the predecessor of the Nanjing Public Transport Group, on May 5, 1931. The New Dictionary of Scientific Biography states that she boarded the ship President Hoover, bound for the United States, in August 1936. Zhang Chengning’s article sets out the contents of the visa file she completed at the U.S. consulate general in Shanghai, dated July 29, 1936: the visa is a non-quota immigrant visa, her nationality is entered as China, her status as student and her family status as unmarried; a Section 6 certificate was issued by the Shanghai Public Safety Bureau on July 6, 1936, and the visa-issuing office is entered as the U.S. consulate general in Shanghai, with July 13, 1936, as the date of issue; the ship is entered as the President Hoover, sailing on August 11, 1936, with San Francisco, CaliforniaCaliforniaCalifornia is a U.S. state on the Pacific coast; its capital is Sacramento and its largest city is Los Angeles. California was admitted to the Union on September 9, 1850, as the 31st state. Its population at the 2020 Census (April 1, 2020) was 39,538,223, the largest of any state.Open the full entry, as the port of entry; the entry on financial guarantee states that she would be financed in full by her father, Zhong-Yi Wu, described in the article’s translation as manager of the traffic department of a Wuxi–Shanghai motor transport company in Shanghai; and the consul’s note records that she submitted a letter from the president of National Central University certifying that she had graduated from it, a letter from her father promising full support and guaranteeing that the purpose of her journey was study, and a letter of introduction, which the article attributes to Chen Bulei (B.L. Chen), translating his title as director of the National Construction Commission in Shanghai; the letter introduced her and her travel companion, Dong Ruofen, attested to the good social standing of both families and vouched for their financial means. The article does not mention the uncle.⁠[10][4][11][12][7]

She had originally planned to attend the University of Michigan. The visa file, as set out in Zhang Chengning’s article, states that she would study physics for four years at the University of Michigan in Ann Arbor to obtain a doctorate, and the consul’s note records that she submitted the University of Michigan’s formal notice admitting her as a student.⁠[13][7]

She visited the University of California, BerkeleyUniversity of California, BerkeleyThe University of California, Berkeley (UC Berkeley) is a campus of the University of California system; the University of California was founded in 1868 through a merger of two institutions and moved to Berkeley, California, in 1873.Open the full entry, first, and the physicist Ernest LawrenceErnest LawrenceErnest Lawrence (in full Ernest Orlando Lawrence, 1901–1958) was an American physicist who invented the cyclotron and received the 1939 Nobel Prize in Physics for its invention and development and for the results obtained with it. He founded and directed the Radiation Laboratory at the University of California, Berkeley, and led the electromagnetic separation of uranium isotopes for the Manhattan Project; Lawrence Berkeley National Laboratory, Lawrence Livermore National Laboratory and element 103, lawrencium, are named after him.Open the full entry persuaded her to stay. Her doctoral research dealt with the fission products of uranium, with Lawrence as her official adviser and Emilio Segrè as her direct supervisor, and she received her Ph.D. in 1940.⁠[1]

She did her graduate work at the Radiation Laboratory directed by Lawrence. Lawrence and Segrè recommended her for faculty posts, but she could not secure one and stayed at the laboratory as a postdoctoral fellow after her degree.⁠[14]

The American Institute of Physics’ record lists her posts there in 1940–1942 as resident fellow and lecturer.⁠[15]

In May 1942 she married the physicist Luke Chia-Liu YuanLuke Chia-Liu YuanLuke Chia-Liu Yuan (1912–2003) was a Chinese-born American experimental physicist and the husband of the physicist Chien-Shiung Wu; he worked mainly at Brookhaven National Laboratory, where he was a senior physicist. He was elected an academician of Academia Sinica in 1959 and chaired the steering committee of Taiwan’s Synchrotron Radiation Research Center from 1983 to 2002.Open the full entry, whom she had met during her studies at Berkeley, in the garden of Robert A. Millikan’s home; because of the fighting in the Pacific, neither family could attend the wedding.⁠[10][16][17]

That year Luke Chia-Liu Yuan took an appointment at RCA in Princeton to work on radar, and the couple moved to the East. She accepted a teaching position at Smith CollegeSmith CollegeSmith College is a liberal arts college for women in Northampton, Massachusetts, United States. Chartered in 1871 under the bequest of Sophia Smith and opened in 1875, it is one of the Seven Sisters schools.Open the full entry in 1942 and in 1943 moved to Princeton UniversityPrinceton UniversityPrinceton University is a private university and Ivy League member in Princeton, New Jersey. Chartered on October 22, 1746 as the College of New Jersey, it moved to Princeton in 1756 and adopted its present name in 1896. Undergraduate education leads to A.B. and B.S.E. degrees and emphasizes small-group discussion, independent research and residential college life. Graduate education spans the humanities, social sciences, natural sciences and engineering. As of October 2026, Christopher L. Eisgruber was president. Its 2026–27 operating budget was $3.407 billion, including $342 million for undergraduate aid.Open the full entry, where she became the first female instructor.⁠[1]

The American Institute of Physics’ record lists her as assistant professor at Smith College (1942–1943) and instructor at Princeton University (1943–1944).⁠[15]

In March 1944 she was invited to join the Manhattan Project at Columbia University as a senior scientist, working first on gaseous diffusion processes for separating uranium isotopes and then on time-of-flight techniques for measuring neutron reaction cross-sections.⁠[1]

She worked at the Substitute Alloy Materials (SAM) Lab, where her tasks included radiation detectors and improved Geiger counters; the gaseous diffusion process was later replicated on a large scale at the K-25 Plant in Oak Ridge. The Atomic Heritage Foundation’s profile states that she is believed to have been the only Chinese person to work on the Manhattan Project.⁠[5]

When the Hanford reactor began shutting down, Enrico FermiEnrico FermiEnrico Fermi (1901–1954) was an Italian-American physicist who received the 1938 Nobel Prize in Physics and in 1942 led the team that achieved the first controlled nuclear chain reaction in Chicago.Open the full entry was asked to explain why and thought that her work on xenon isotopes might help; asked to comment, she pointed out that xenon-135 has a huge affinity for neutron capture and a short lifetime.⁠[1]

After the war Columbia University kept her on. The American Institute of Physics’ record shows her as a scientist in the university’s Division of War Research in 1944–1946 and as a research associate in 1946–1952.⁠[5][15]

Fermi had outlined his theory of beta decay in 1933, but by 1945 the existing experiments disagreed with it. She traced the problem to the experiments themselves: electrons scattered as they left thick sources, and magnetic spectrometers with iron cores gave wrong field values because of hysteresis. Using an old iron-free solenoid spectrometer at Columbia University and ever thinner sources, she obtained results that confirmed Fermi’s theory in detail.⁠[1]

In 1949 she and her student Irving ShaknovIrving ShaknovIrving Shaknov (died 1952) was a physicist who studied under Chien-Shiung Wu at Columbia University, where he received his doctorate. Their experiment on the angular correlation of annihilation photons, carried out in 1949 and published in 1950, has since been described by several writers as the first to clearly demonstrate quantum entanglement; he then joined the Operations Evaluation Group, which carried out studies for the United States Navy, and was killed on a flight mission in the Korean War.Open the full entry carried out an experiment in the basement of Pupin Hall at Columbia University. The Atomic Heritage Foundation’s profile describes it as a quantum entanglement experiment and judges that its significance was not officially recognized in her lifetime and was underscored by the 2022 Nobel PrizeNobel PrizeThe Nobel Prize is an international award established under the will of Alfred Nobel, comprising five prizes in physics, chemistry, physiology or medicine, literature and peace, awarded since 1901; its funds are managed by the Nobel Foundation, whose Board is based in Stockholm. The Sveriges Riksbank Prize in Economic Sciences in Memory of Alfred Nobel, established in 1968, is not a Nobel Prize.Open the full entry for work on entanglement. An article published in Physics Today in 2024 states that the measurement was made in November 1949, that accelerated deuterons were used to bombard copper foil and the resulting copper-64 served as the positron source, and that the whole measurement ran continuously for 30 hours; the results appeared on January 1, 1950, as a letter in the Physical Review (volume 77, page 136), giving an asymmetry ratio of 2.04 ± 0.08 against a theoretical prediction of 2.00, and the article calls this “the first conclusive verification of photon entanglement.” Pupin Hall is named for the physicist Michael I. PupinMichael I. PupinMichael I. Pupin (born 1854 or 1858, died 1935) was a Serbian American physicist and inventor who taught at Columbia University from 1889 to 1931 and is known for extending the range of long-distance telephony by placing loading coils along telephone lines. His autobiography, From Immigrant to Inventor, won the 1924 Pulitzer Prize for biography.Open the full entry, a former member of the university’s physics faculty. After completing his Ph.D., Irving Shaknov joined the Operations Evaluation Group, which served the United States Navy; he was killed in the Korean War on the night of May 14, 1952, at the age of 30. An article of the American Institute of Physics states that David Bohm later came upon the paper published in 1950, that its results agreed with a calculation by Yakir Aharonov, and that this led to a paper the two published in 1957. The Physics Today article adds that she later carried out, with her graduate students Leonard Kasday and John Ullman, a new experiment on the angular distribution of Compton-scattered photons, published in Nuovo Cimento B in 1975.⁠[5][18][19][20]

The Wolf Foundation’s biography states that she demonstrated that the two photons produced in electron–positron annihilation are polarized at right angles to each other, as Dirac’s theory predicts, which showed that the electron and the positron have opposite parity.⁠[21]

In 1952 she was promoted to associate professor at Columbia University, becoming the first woman with tenure in its physics department.⁠[1]

In 1954 she became a citizen of the United States.⁠[10]

In 1958 she was promoted to full professor, was elected to the National Academy of Sciences, received the Research Corporation Award and was awarded an honorary Sc.D. by Princeton University, the first time the university had given that degree to a woman.⁠[1]

The National Park Service’s profile describes her as only the seventh woman elected to the National Academy of Sciences.⁠[10]

The Rochester conference on high-energy physics in April 1956 discussed the so-called θ–τ puzzle. That year Tsung-Dao LeeTsung-Dao LeeTsung-Dao Lee (1926–2024) was a Shanghai-born American physicist who taught for decades at Columbia University. In 1956 he and Chen Ning Yang proposed that parity might not be conserved in weak interactions, for which they shared the 1957 Nobel Prize in Physics; from the 1970s he helped advance high-energy physics and the training of physicists in China.Open the full entry of Columbia University and Chen Ning YangChen Ning YangChen Ning Yang (1922–2025) was a theoretical physicist born in Hefei, Anhui, China, who shared the 1957 Nobel Prize in Physics with Tsung-Dao Lee for their investigation of the parity laws. In 1954 he and Robert L. Mills formulated non-Abelian gauge theory (Yang–Mills theory), and he worked in turn at the Institute for Advanced Study, Stony Brook University and Tsinghua University.Open the full entry of the Institute for Advanced Study proposed that parity might not be conserved in weak interactions.⁠[1][6]

Tsung-Dao Lee sought her advice on experiments, and she chose the beta decay of cobalt-60 as the test because the spin of that nucleus could be polarized in a well-determined direction. She worked with Ernest AmblerErnest AmblerErnest Ambler (1923–2017) was a British-born American physicist who joined the National Bureau of Standards in 1953 to work in low-temperature physics and was one of the four bureau physicists who carried out the cobalt-60 parity experiment of 1956–1957 with Chien-Shiung Wu. He became the bureau’s acting director in 1975 and its director in 1978, presided over its change into the National Institute of Standards and Technology in 1988 and retired in 1989.Open the full entry, Raymond W. HaywardRaymond W. HaywardRaymond W. Hayward (1921–2001) was a nuclear physicist at the National Bureau of Standards of the United States. In 1956–1957, with Chien-Shiung Wu, Ernest Ambler, Dale D. Hoppes and Ralph P. Hudson, he carried out the cobalt-60 beta-decay experiment that showed parity is not conserved in weak interactions.Open the full entry, Dale D. HoppesDale D. HoppesDale D. Hoppes (born 1928) was a nuclear physicist at the National Bureau of Standards of the United States (later the National Institute of Standards and Technology), where he later led the Radioactivity Group. In 1956–1957, with Chien-Shiung Wu, Ernest Ambler, Raymond W. Hayward and Ralph P. Hudson, he carried out the cobalt-60 beta-decay experiment that showed parity is not conserved in weak interactions.Open the full entry and Ralph P. HudsonRalph P. HudsonRalph P. Hudson (1924–2016) was a British-born American low-temperature physicist who joined the National Bureau of Standards in 1951, headed its Cryogenic Physics Section and then its Heat Division, and was one of the four bureau physicists who carried out the cobalt-60 parity experiment of 1956–1957 with Chien-Shiung Wu. From 1980 to 1989 he was Director of Publications at the Bureau International des Poids et Mesures in France and editor of the journal Metrologia.Open the full entry of the National Bureau of Standards in Washington and spent the summer of 1956 testing the setup. Ralph P. Hudson recounted that she first approached Henry Boorse of Columbia University and Mark W. Zemansky of the City College of New York, who suggested that she contact Ernest Ambler. Magdolna Hargittai writes in Physics World that she met Ernest Ambler in Washington in September 1956 and that the two invited three of his colleagues to join them: Ralph P. Hudson, an expert in cryogenics, and the radiation-detection experts Raymond W. Hayward and Dale D. Hoppes. A National Institute of Standards and Technology blog article quotes Ernest Ambler as saying in an oral history that she contributed to the beta-particle detection and counting side of the experiment, as did Raymond W. Hayward and Dale D. Hoppes, and that he and Ralph P. Hudson contributed the low-temperature side.⁠[1][22][23][24]

The cobalt-60 nuclei were embedded in a cerium magnesium nitrate crystal kept at 0.01 K; electrons were detected with an anthracene crystal attached to a 4-foot-long light pipe, the anisotropy of the gamma rays measured the polarization of the sample, and the asymmetry was measured by reversing the polarizing field. By the end of December 1956 a large effect had been observed. The National Institute of Standards and Technology’s account gives the temperature to which the sample was cooled as about 0.003 K; the figure of 0.01 K is that of the National Academy of Sciences’ memoir. Hargittai’s article states that she had teaching duties at Columbia University and could not be at the National Bureau of Standards all the time, and that she was not present on December 27, 1956, when her colleagues there saw the first signs of the asymmetry. The National Institute of Standards and Technology has published page 90 of Ernest Ambler’s notebook, which records that day’s experiment, and notes that the first of two successful runs began at 12:04 and that Ralph P. Hudson later added “PARITY NOT CONSERVED!” at the top of the page.⁠[1][25][23]

The experiment found that more electrons were emitted downward than upward, and that when the field was reversed more were detected in the upward direction, which showed that parity is violated in the weak interaction.⁠[26]

The paper “Experimental Test of Parity Conservation in Beta Decay” appeared in the Physical Review in 1957. Leon Lederman, Richard Garwin and Marcel Weinrich at Columbia University’s Nevis cyclotron laboratory then detected the asymmetry in muon decay, and Telegdi and Friedman in Chicago ran a similar experiment with emulsions. Wolfgang PauliWolfgang PauliWolfgang Pauli (1900–1958) was a Vienna-born theoretical physicist who received the 1945 Nobel Prize in Physics for the discovery of the exclusion principle, also called the Pauli principle, and who in 1930 proposed the neutral particle later named the neutrino; he was professor of theoretical physics at ETH Zurich from 1928 until his death.Open the full entry wrote to congratulate her on January 19, 1957. In that letter he wrote, “I congratulate you (to the contrary of myself).” Four days earlier, on January 15, 1957, she and her colleagues, among them Tsung-Dao Lee, had announced the discovery at a press conference held at Columbia University. A National Institute of Standards and Technology blog article states that the team was finally convinced at about 2 a.m. on January 9, 1957, and that the paper was published in the February 15, 1957, issue of the Physical Review. Magdolna Hargittai writes that the paper listed her as first author, followed by the National Bureau of Standards authors in alphabetical order, and that this arrangement was suggested by the National Bureau of Standards team; she quotes Ernest Ambler as saying in correspondence with her, “I invited her to go first in the list of names out of courtesy,” because she had brought the preprint of the paper by Tsung-Dao Lee and Chen Ning Yang before its publication. The team then ran a second experiment with cobalt-58, a positron emitter, in which the positrons were emitted preferentially along the direction of the nuclear spin. In 1957 she traveled to Israel by plane with Wolfgang Pauli, who afterward wrote to his sister, “Frau Wu is as obsessed with physics as I was in my young years.”⁠[1][8][24][23][25]

The 1957 Nobel Prize in Physics was awarded jointly to Chen Ning Yang and Tsung-Dao Lee “for their penetrating investigation of the so-called parity laws which has led to important discoveries regarding the elementary particles.”⁠[27]

She was not among the laureates. The National Park Service’s profile states that by 1966 she had received at least seven Nobel Prize nominations.⁠[28]

Columbia News writes that some attribute the committee’s omission of her to gender bias, while others point to the committee’s rules.⁠[29]

In 1958 Richard P. FeynmanRichard FeynmanRichard Feynman (Richard Phillips Feynman, 1918–1988) was an American theoretical physicist who rebuilt quantum electrodynamics with the path-integral formulation and Feynman diagrams, for which he shared the 1965 Nobel Prize in Physics with Julian Schwinger and Sin-Itiro Tomonaga. He took part in the Manhattan Project during World War II and then taught for decades at the California Institute of Technology, where his introductory physics course became The Feynman Lectures on Physics; in 1986, as a member of the presidential commission investigating the space shuttle Challenger accident, he used ice water to demonstrate that the O-ring lost its resilience at low temperature.Open the full entry and Murray Gell-Mann proposed the conservation of the vector current (CVC) in nuclear beta decay. In 1963 she and two other research physicists at Columbia University confirmed the theory experimentally.⁠[6]

The experiment, on the decays of boron-12 and nitrogen-12, was carried out at Columbia University with Luke Mo and students and demonstrated weak magnetism.⁠[1]

In 1964 she received the Cyrus B. Comstock Award; in 1962 she had received the John Price Wetherill Medal of the Franklin Institute. Ralph P. Hudson recorded that the 1962 medal was awarded to the full team of the parity experiment, that the National Bureau of Standards honored the members of its own staff on the team with the Department of Commerce’s Gold Medal for exceptional service, and that in 1964 the bureau added its Samuel Wesley Stratton Award.⁠[1][22]

The Museum of Chinese in America’s profile describes her as the first woman to win the Comstock award.⁠[13]

At a symposium at the Massachusetts Institute of Technology in 1964 she addressed gender bias in science, asking “whether the tiny atoms and nuclei, or the mathematical symbols, or the DNA molecules have any preference for either masculine or feminine treatment.”⁠[10]

From 1966 to 1971 she made a thorough study of the X-ray spectra of muonic atoms and became interested in biological problems, especially the structure of hemoglobin; her Mössbauer studies of hemoglobin clarified its structure.⁠[21]

Her later work also included double-beta-decay experiments on calcium-48 and selenium-82, tests of time-reversal symmetry using the Mössbauer effect, condensed-matter studies and research on sickle-cell hemoglobin.⁠[1]

In 1972 she led an ad hoc committee that presented Columbia University’s administration with demands for equal opportunity, including that the salaries of minority and women faculty match those of their male colleagues; the university had 11 women on its full-time faculty that year.⁠[30]

In 1973 she was appointed the first Michael I. Pupin Professor of Physics. Columbia News lists Columbia’s Pupin Medal among her awards.⁠[1][29]

After the Second World War she had planned a trip to China, but the civil war prevented it and her father advised her not to return. She was not able to go back until 1973, by which time her parents had died. An article in China Science Daily states that in 1957 the Chinese government had asked her father to write inviting her to return. The article in Mathematical Culture states that her older brother died of illness in 1958, her father in 1959 and her mother in 1962. A column by Chen Siyi on the China Times news site states that because the U.S. government at the time strictly limited its citizens’ travel to communist countries, she could not return to China for the funerals of her relatives. The Mathematical Culture article states that on their journey of 1965 she and Luke Chia-Liu Yuan met in Hong Kong her uncle Wu Zhuozhi, who had paid for her studies abroad, and Wu Jianhao, her only surviving brother; the China Science Daily article states that in 1965 the authorities concerned arranged for her uncle, her younger brother and others to travel to Hong Kong and meet the couple in secret. A 2024 article in The Paper states that when a delegation of Chinese high-energy physicists toured the five main high-energy physics laboratories of the United States in June 1973, Tsung-Dao Lee, Luke Chia-Liu Yuan, she and other physicists of Chinese descent received it. The commemorative article in The Paper states that she and Luke Chia-Liu Yuan returned to China in October 1973 and were received by Premier Zhou Enlai; the article in Mathematical Culture dates their return to mainland China to September 1973, gives the length of the trip as 53 days and adds that Zhou Enlai gave a dinner for them in the Anhui Room of the Great Hall of the People. The New Dictionary of Scientific Biography states that her meeting with Zhou Enlai lasted six hours. Bai Junhe, a son-in-law of Yuan KehuanYuan KehuanYuan Kehuan was the sixth son of Yuan Shikai; he went to Europe in 1913 and attended Cheltenham College in England. His son-in-law Bai Junhe says in an oral account that he entered industry in North China in 1926, served as assistant manager and then general manager of Qixin Yanghui Gongsi (the Qixin cement company), and died in 1956.Open the full entry, says in an oral account that on this visit the couple went to Tianjin to see relatives and called on Chen Zheng, the wife of Yuan Kehuan. The Mathematical Culture article states that the uncle and the younger brother whom she had met in Hong Kong were persecuted to death, one after the other, during the Cultural Revolution and that her parents’ graves were destroyed; the National Park Service’s profile states that her uncle and brother were “killed in the Chinese Cultural Revolution” and that her parents’ tombs had been destroyed. The New Dictionary of Scientific Biography, by contrast, states that she mourned never having seen her parents and brothers again before they died in the 1950s and 1960s. The Jinling Dang’an article on Wu Zhuozhi states that he died of illness in Nanjing in 1967. A report by the archives of Southeast University states that from her first return in 1973 she went back to China nine times in her life, visited the Mingde school on five of those trips, and paid for a laboratory building, equipment and teacher training at the school.⁠[10][2][4][31][8][12][32][11][33][34]

In 1975 she became president of the American Physical Society, the first woman to hold the office; that year she also received the National Medal of Science and the society’s Tom Bonner Prize.⁠[1]

In 1975 her pay as a professor was raised to equal that of her male colleagues.⁠[10]

From 1975 to 1982 she was a member of the Advisory Committee to the Director of the National Institutes of Health. In December 1977 she, Tsung-Dao Lee and Luke Chia-Liu Yuan wrote jointly to Zhang Wenyu, director of the Institute of High Energy Physics of the Chinese Academy of Sciences, proposing that China build an electron–positron collider and choose an economical design with rich physics goals.⁠[15][35][8]

In 1978 she became the first recipient of the Wolf Prize in Physics, awarded “for her persistent and successful exploration of the weak interaction which helped establish the precise form and the non conservation of parity for this new natural force.” The Wolf Foundation’s biography states that her experimental work on beta decay and weak interactions was mostly carried out from 1948 to 1963.⁠[21][1]

She retired in 1981 and afterward devoted much effort to educational programs in mainland China and Taiwan. In 1981 she and Luke Chia-Liu Yuan proposed that a synchrotron radiation accelerator be built in Taiwan, and in 1983 the Executive Yuan agreed to establish a synchrotron radiation research center. A publication of the National Synchrotron Radiation Research Center states that she served on the center’s steering committee from its creation by the Executive Yuan in 1983 until her death. The commemorative article in The Paper states that early in 1981, after China’s high-energy proton accelerator project was cancelled, she and Luke Chia-Liu Yuan conferred with Tsung-Dao Lee on how to advance a base for experimental high-energy physics in China; soon afterward Zhu Hongyuan and Xie Jialin of the Institute of High Energy Physics of the Chinese Academy of Sciences came to the United States and met Tsung-Dao Lee, W. K. H. Panofsky, her, Luke Chia-Liu Yuan and experts from several American high-energy physics laboratories, and the meeting agreed that a 2 × 2.2 GeV electron–positron collider was the best plan for China. A 2024 article in The Paper states that from June to October 1982 a design team led by Xie Jialin and Zhang Houying completed the design of the main parts of the Beijing Electron–Positron Collider in the United States, where it was received by Tsung-Dao Lee, her and other Chinese American high-energy physicists.⁠[1][17][36][8][31]

After retirement she held the title of Michael I. Pupin Professor Emeritus.⁠[15]

In 1984 the University of PaduaUniversity of PaduaUniversity of Padua (Italian: Università degli Studi di Padova) is a state university in Padua, Italy, which dates its foundation to 1222, when a group of students and teachers moved there from the University of Bologna. Galileo Galilei taught there for 18 years, and in 1678 it awarded a degree to Elena Lucrezia Cornaro Piscopia, whom the university describes as the first woman in the world to receive a university degree.Open the full entry awarded her an honorary Sc.D. The degree was conferred in the university’s Galileo Galilei Aula Magna. In 1988 she returned to her hometown to preside over the commemoration of the centenary of her father’s birth and set up the scholarship foundation named after him; the article in Mathematical Culture describes the gift as nearly US$1 million of her and Luke Chia-Liu Yuan’s personal savings, while an article on the website of the China Zhi Gong Party describes it as US$1 million from the prize money she had received over the years.⁠[1][4][37]

In 1990 an asteroid was named 2752 Wu Chien-Shiung; it had been discovered by astronomers at the Zijinshan Astronomical Observatory in Nanjing. A Xinhua report states that in 1992 she set up a laboratory bearing her name at Southeast University. The same report places the founding of the foundation named after her father after that date, which differs from the 1988 given by the other two sources.⁠[10][30][38]

In 1994 she was elected one of the first foreign members of the Chinese Academy of Sciences. In the autumn of 1995 Chen Ning Yang, Tsung-Dao Lee, Samuel C. C. Ting and Yuan T. Lee, celebrating her birthday in Taiwan, jointly initiated an academic foundation bearing her name.⁠[8][17]

She died in New York City on February 16, 1997, following a stroke. Luke Chia-Liu Yuan carried her ashes to China to rest at the Ming De School, where the memorial was designed by Tsung-Dao Lee. On April 5, 2004, his ashes were buried with hers. An article on the website of the China Zhi Gong Party states that, in accordance with her wishes, her ashes were buried on the school grounds beneath a crape myrtle planted by her father, that the name of the memorial garden was inscribed by Chen Ning Yang and that the epitaph was written by Tsung-Dao Lee; a China Daily report states that the epitaph was written by her biographer Chiang Tsai-chien. The Zhi Gong Party article also states that the inscription on Luke Chia-Liu Yuan’s tombstone was written by Yuan T. Lee and its epitaph by Samuel C. C. Ting.⁠[1][37][39][40]

Columbia News gives her age at death as 84. The release that Columbia University issued at the time states that she died on the afternoon of Sunday, February 16, in Manhattan, aged 84. The release reports Luke Chia-Liu Yuan as saying that she had suffered a stroke almost two years earlier and another on that Sunday.⁠[29][41]

Her husband, Luke Chia-Liu Yuan, worked at Brookhaven National Laboratory from 1949. The National Academy of Sciences’ memoir dates his Ph.D. from the California Institute of Technology to 1937, while Brookhaven National Laboratory’s 1958 bulletin and his Academia Sinica record give 1940; in 1946 he became a research associate at Princeton University.⁠[1][42][43]

Luke Chia-Liu Yuan was a grandson of Yuan ShikaiYuan ShikaiYuan Shikai (1859–1916) was a Chinese army leader and reformist minister of the late Qing dynasty and the first president of the Republic of China, from 1912 to 1916. The modern army he trained at Xiaozhan, Tianjin, grew into the Beiyang Army; in 1915–1916 he proclaimed a monarchy with himself as emperor, cancelled it in March 1916 and died on June 6 of that year.Open the full entry. Her father-in-law, Yuan KewenYuan KewenYuan Kewen (1890–1931), art name Hanyun, was the second son of Yuan Shikai, known as a poet, calligrapher and collector of Song and Yuan printed books, old coins and stamps, and as an amateur performer of Peking opera and Kunqu. He remonstrated in verse when his father prepared to take the throne; the physicist Luke Chia-Liu Yuan was his son.Open the full entry, was the second son of Yuan Shikai; an article by Wang Zhenliang lists his four sons, of whom Luke Chia-Liu Yuan was the third. She and Luke Chia-Liu Yuan gave nearly US$1 million of their personal savings to set up a scholarship foundation named after her father, Zhong-Yi Wu, which rewards outstanding teachers and students of the Mingde school. An article by Shan Jia in the Southeast University alumni magazine Dongnan Daxue Dongli Dianqi Ren (2016, no. 8) states that she said she always found it incomprehensible to see couples constantly at odds; the article attributes this to her parents’ devotion to each other and sees in it the root of her own close marriage to Luke Chia-Liu Yuan. The article also states that in 1960 she wrote to an old friend that someone had just telephoned to say the next day was the Chinese lunar New Year, that at every holiday and festival she could not help missing her home town, all the more because her father and her elder brother had both died and her mother was old and often ill.⁠[44][16][4][40][45][46]

The couple’s son, Vincent YuanVincent YuanVincent Yuan (born 1947) is a physicist whose research has been carried out at Los Alamos National Laboratory and the son of Chien-Shiung Wu and Luke Chia-Liu Yuan; he took part in the TRIPLE Collaboration’s research on parity violation in neutron resonances and was first author of an experiment that measured the temperature of a shock wave by neutron resonance spectroscopy.Open the full entry (Wei-Cheng Yuan), was born in Princeton in 1947 and also became a physicist; she also had a granddaughter, Jada YuanJada YuanJada Yuan is a journalist who was a contributing editor at New York magazine, served in 2018 as the first “52 Places Traveler” of The New York Times and was afterward a reporter at The Washington Post until February 2026; she is a granddaughter of the physicists Chien-Shiung Wu and Luke Chia-Liu Yuan.Open the full entry. On December 13, 2021, The Washington PostThe Washington PostThe Washington Post is an American daily newspaper founded in Washington in 1877, known for its role in the Pentagon Papers case and the Watergate investigation. Run by the Meyer–Graham family for eighty years from 1933, it has been owned personally by Jeff Bezos since 2013.Open the full entry published a long essay by Jada Yuan about her grandmother, in which she writes that her father studied physics and received his Ph.D. at Columbia University; NPR refers to the essay by the title “Discovering Dr. Wu.”⁠[1][47][48]

At the stamp dedication on February 11, 2021, the United States Postal Service identified Vincent Yuan as a scientist at Los Alamos National Laboratory. The release that Columbia University issued on her death describes Vincent Yuan as living in Albuquerque, New MexicoNew MexicoNew Mexico is a state in the Southwestern United States. Its capital is Santa Fe and its largest city is Albuquerque. It was admitted to the Union on January 6, 1912, as the 47th state, and had a population of 2,117,522 in the 2020 census (April 1, 2020).Open the full entry, and as a research scientist at Los Alamos National Laboratory. The release adds that he earned his bachelor’s degree in 1967 and a doctorate in physics in 1977, both from Columbia University. The meetings archive of the American Physical Society lists, under its April 2006 meeting, his invited talk “Chien-Shiung Wu as a Person and a Scientist,” given with the affiliation Los Alamos National Laboratory; the abstract says that he would discuss his view of her from his vantage point as her son. A Los Alamos National Laboratory publication reporting on the stamp calls him a scientist in the laboratory’s Applied and Fundamental Physics group. In her 2021 essay Jada Yuan writes that her father, at 74, was still working on classified nuclear physics projects.⁠[49][41][50][51][47]

Her book Beta Decay, written with S. A. Moszkowski, was published by John Wiley in New York in 1966; in 1950 she had published the review “Recent investigation of the shapes of beta-ray spectra.” The chronology of the Tsung-Dao Lee Library at Shanghai Jiao Tong University records that in 1965–1966 she and Tsung-Dao Lee completed a review article on weak interactions.⁠[1][35]

The Atomic Heritage Foundation’s profile dates Beta Decay to 1965 and calls it still a standard reference for nuclear physicists.⁠[5]

In 1998 she was inducted into the National Women’s Hall of Fame. On November 9, 2011, an American Physical Society “historic site” plaque was unveiled at the University of the District of Columbia in Washington; it records that in 1956 she, Ernest Ambler, Raymond W. Hayward, Dale D. Hoppes and Ralph P. Hudson performed an experiment at the site, which was then on the campus of the National Bureau of Standards.⁠[1][52][53]

For the 100th anniversary of her birth in 2012, Shanghai held a week of festivities and a bronze statue of her was unveiled in the courtyard of Mingde Middle School in her hometown of Liuhe. A Xinhua report on the centenary events held in Taicang states that nearly 500 people attended the commemorative meeting on May 30, 2012, and that an exhibition hall devoted to her opened on the morning of May 31. An article in China Science Daily states that Southeast University, her alma mater, has built a Chien-Shiung Wu Memorial Hall that keeps and displays her belongings and the record of her life; the New Dictionary of Scientific Biography states that many of her unpublished papers are deposited there. The play Chun Shi, staged in 2020, draws on an episode in the lives of Jing-Wei Gu, her and Ding Xielin, the director of the Institute of Physics.⁠[29][38][2][12][9]

On February 11, 2021, the United States Postal Service issued the Chien-Shiung Wu Forever stamp, with New York City as the first-day-of-issue city and a virtual dedication ceremony. The original art was by Kam Mak and the design by art director Ethel Kessler; it shows her in a black-and-white high-collared qipao. The release calls her “one of the most influential nuclear physicists of the 20th century” and notes that the name on the stamp follows the Wade-Giles spelling.⁠[49]

Columbia News notes that she was the first Chinese American physicist, and after Maria Goeppert Mayer and Sally Ride the third female physicist, to be honored on a U.S. commemorative stamp.⁠[29]

The National Park Service’s profile judges that her parity experiment contributed significantly to particle physics and the development of the Standard Model.⁠[28]

An article in Physics World argues that she should have shared the 1957 Nobel Prize in Physics, while noting that two other groups were carrying out similar experiments at the time. In December 2012 Chen Ning Yang published “Weighing in on Wu’s Legacy,” on the parity nonconservation experiment of 1956–1957, in Physics World. Ralph P. Hudson wrote that afterward hardly a speaker or writer referred to the event as anything but “the Wu experiment.” The National Academy of Sciences’ memoir quotes Tsung-Dao Lee: “C. S. Wu was one of the giants of physics. In the field of beta-decay, she had no equal.”⁠[26][54][22][1]

Manhattan Project National Historical Park: Official website: https://www.nps.gov/mapr/ (opens in a new window).⁠[55]

Wolf Foundation: Official website: https://wolffund.org.il/ (opens in a new window).⁠[56]