Portrait Highlight - Wu Chien-Shiung - Chinese-American particle and experimental physicist

Wu Chien-Shiung (吳健雄; May 31st, 1912 – February 16th, 1997) was a Chinese-American particle and experimental physicist who made significant contributions in the fields of nuclear and particle physics. Her nicknames include the "First Lady of Physics", the "Chinese Madame Curie" and the "Queen of Nuclear Research”. She is best known for conducting the Wu Experiment, which proved that parity is not conserved. This discovery resulted in her (male) colleagues Tsung-Dao Lee and Chen-Ning Yang winning the 1957 Nobel Prize in Physics, while Wu herself was awarded the inaugural Wolf Prize in Physics in 1978.

Chien-Shiung was born in the town of Liuhe, Taicang in Jiangsu province, China, the second of three children. She and her father, Wu Zhong-Yi (吳仲裔), were extremely close, and he encouraged her interests passionately, creating an environment where she was surrounded by books, magazines, and newspapers. He was an engineer who encouraged women's equality and became a notable activist during the revolution led by Sun Zhongshan that modernised the country. He led a local militia that wiped out local bandits and completely modernised the little town of Liuhe, while seeking girls from rich and poor families to join his new school. Chien-Shiung’s mother, Fan Fu-Hua, was a teacher who also valued education for both genders.

As a child Chien-Shiung attended the Ming De School, a school for girls founded by her father. Unlike the other girls, she didn’t play often outside. Instead she would stay inside and listen to the newly invented radio. She also enjoyed poetry and Chinese classics such as the Analects, and western literature on democracy that her father promoted at home. Until she learnt to read she would listen to her father recite paragraphs from scientific journals instead of children's stories. In 1923, at the age of 10, she left her hometown of Liuhe to go to the Suzhou Women's Normal School No. 2, which was fifty miles from her home. This was a boarding school with classes for teacher training as well as for regular high school, and introduced subjects in science that slowly became a growing passion for the young Chien-Shiung. Although she ended up doing scientific research, Chien-Shiung’s writing was considered outstanding thanks to her early training and her Chinese calligraphy was widely praised. In 1929 she graduated at the top of her class and was admitted to National Central University in Nanjing. She spent the summer before starting at the university, preparing for her studies with gusto. She felt that her background and training in Suzhou Women's Normal School were insufficient to prepare her for majoring in science. Her father encouraged her dedication and bought her three books to help with her self-study: trigonometry, algebra, and geometry.

Between 1930-1934, Chien-Shiung studied at National Central University and first majored in mathematics but later transferred to physics. Whilst at the university he became involved in student politics. Relations between China and Japan were tense at this time, and students were urging the government to take a stronger line with Japan. She led protests that included a sit-in at the Presidential Palace in Nanjing, where the students were met by Chiang Kai-shek. Following her graduation, she did graduate-level study in physics and worked as an assistant at Zhejiang University for two years. She then became a researcher at the Institute of Physics of the Academia Sinica where her supervisor was Gu Jing-Wei, a female professor who had earned her PhD abroad at the University of Michigan and encouraged Chien-Shiung to do the same. When she was accepted by the University of Michigan, it was her uncle, Wu Zhou-Zhi, who provided the necessary funds for her to go. In August 1936 she set sail for the United States with her female friend and chemist from Taicang, Dong Ruo-Fen (董若芬). She would never see her parents again for though her family would survive the Second World War, she would be unable to visit China (and the remaining members of her family) again until the 1970s.

On her arrival in the US, Chien-Shiung was shocked at the sexism in American society when she learned that at Michigan women were not even allowed to use the front entrance. She decided instead, that she would prefer to study at the more liberal Berkeley in California where she met physicist Luke Chia-Liu Yuan, who showed her the Radiation Laboratory, where the director was Ernest O. Lawrence, who would soon win the Nobel Prize for Physics in 1939 for his invention of the cyclotron particle accelerator. Her Berkeley classmates included Robert R. Wilson and George Volkoff; her closest friends included post-doctoral student Margaret Lewis and Ursula Schaefer. Chien-Shiung sorely missed Chinese cuisine and was not impressed with the food at Berkeley, so she always dined with her friends at her favourite restaurant, the Tea Garden, where they would get free meals that were not part of the menu due to her friendship with the owner.

At the end of her first year she applied for a scholarship, but there was prejudice against Asian students from the department head Birge, and both Chien-Shiung and Luke were instead offered a readership with a lower stipend. Luke then applied for, and secured, a scholarship at Caltech. Chien-Shiung made rapid progress in her education and her research. Although Lawrence was officially her supervisor, she also worked closely with the famous Italian physicist Emilio Segrè and quickly became his favourite student. Together they conducted studies on beta decay, including xenon, which would provide important results in the future of nuclear bombs. According to Segrè, Chien-Shiung was a popular student who was talented and attractive. In his autobiography, Nobel laureate Luis Alvarez said of Chien-Shiung, "I got to know this graduate student in this idle time. She used the same room next door, and was called 'Gee Gee (her nickname at Berkeley)'. She was the most talented and most beautiful experimental physicist I have ever met.” Segrè recognised Chien-Shiung's brilliance and compared her to her own heroine, Marie Curie, whom she always quoted, but said that Chien-Shiung was more "worldly, elegant, and witty." Meanwhile, Lawrence described her as "the most talented female experimental physicist he had ever known, and that she would make any laboratory shine.”

On completing her PhD in June 1940, Chien-Shiung was elected to Phi Beta Kappa, the US academic honour society. In spite of Lawrence and Segrè's recommendations, she could not secure a faculty position at a university, so she remained at the Radiation Laboratory as a post-doctoral fellow.

In May 1942, Chien-Shiung and Luke were married at the home of Robert Millikan, Luke's academic supervisor and the President of Caltech. Due to the outbreak of the Pacific War, neither the bride's nor the groom's families were able to attend. After the wedding Chien-Shiung and Luke moved to the East Coast of the US, where Chien-Shiung became an assistant professor at Smith College, a private women's college in Northampton, Massachusetts, while Luke worked on radar for RCA. However, she found the job frustrating as her duties involved teaching only, and there was no opportunity for research. She appealed to Lawrence, who wrote letters of recommendation to a number of universities. Smith responded by making Chien-Shiung an associate professor and increasing her salary. She then accepted a job from Princeton University in New Jersey as the first female faculty member in the history of the physics department, where she taught for officers of the navy.

In March 1944, Chien-Shiung joined the Manhattan Project's Substitute Alloy Materials (SAM) Laboratories at Columbia University. The role of the SAM Laboratories, headed by Harold Urey, was to support the Manhattan Project's gaseous diffusion (K-25) program for uranium enrichment. Chien-Shiung worked alongside James Rainwater in a group led by William W. Havens, Jr., whose task was to develop radiation detector instrumentation. Chien-Shiung, like most involved physicists in their later years, distanced herself from the Manhattan Project due to its destructive outcome and recommended to the Taiwanese president Chiang Kai-shek in 1962 to never build nuclear weapons.

After the end of the war in August 1945, Chien-Shiung accepted an offer of a position as an associate research professor at Columbia. She would remain at Columbia for the rest of her career, and was first named associate professor in 1952, which made her the first woman to become a tenured physics professor in university history. It was only after the second world war that communication with China was restored, and Chien-Shiung received a letter from her family. However, plans to visit China were disrupted by the civil war and communist takeover, led by Mao Zedong, and Chien-Shiung would not be able to return to China until decades later to meet her surviving uncle and younger brother. Due to the war, many were displaced and younger students would leave for the United States, while scholars in America could not return home. She missed China deeply and would often go with Luke to buy fabric to make her own qipao (also known as a cheongsam) as a way to remember the country, which she always wore under her lab coat. In 1947 Chien-Shiung gave birth their her son, Vincent (袁緯承) who would later grow up to become a physicist like his parents and attend Columbia to follow his mother’s footsteps.

Since her passport had been issued by the Kuomintang government, now overthrown by the communists, Chien-Shiung found it difficult to travel abroad as places such as Switzerland did not recognise her passport. Sometimes her friend in Switzerland, physicist Wolfgang Pauli, had to secure her special visas just to enter the country. This eventually led to her decision to stay in the United States. With the help of Columbia chairman Charles H. Townes, Chien-Shiung would become a US citizen in 1954.

Chien-Shiung became a full professor in 1958, and later on was named the first Michael I. Pupin Professor of Physics in 1973. Her discoveries proved to be important in physics and her work even crossed over to biology and medicine, where her contributions became extremely influential to certain studies on the molecular changes in red blood cells that caused sickle-cell disease or anaemia. She later wrote a textbook with Steven Moszkowski entitled Beta Decay, which was published in 1966. It was the first comprehensive study on beta decay, and the book quickly became the standard reference textbook on the subject; it remains one of the standard references in the 21st century.

In 1958 her older brother died. Her father followed him the very next year, and her mother would follow him in 1962. The United States State Department had imposed severe restrictions on travel to Communist countries by its citizens, so Chien-Shiung was not permitted to visit mainland China to attend their funerals. She was only able to see her uncle, Wu Zhou-Zhi, and younger brother, Wu Chien-Hao, on a trip to Hong Kong in 1965. After the 1972 Nixon visit to China, relations between the two countries improved, and she visited China again in 1973. By the time she returned, her uncle and brother had perished in the Cultural Revolution, and the tombs of her parents had been destroyed.

During the late 20th century, Chien-Shiung continued to be seen as the top experimental physicist in the world and many continued to ask for her guidance in proving certain hypotheses. In later life, she became more outspoken. She protested the imprisonment in Taiwan of the in-laws of physicist Kerson Huang in 1959 and of the journalist Lei Chen in 1960. With the help of her teacher Hu Shih, Huang's in-laws were eventually released on bail and Lei's sentence was reduced to ten years by President Chiang Kai-shek. In 1964, she spoke out against gender discrimination at a symposium at the Massachusetts Institute of Technology. "I wonder," she asked her audience, "whether the tiny atoms and nuclei, or the mathematical symbols, or the DNA molecules have any preference for either masculine or feminine treatment," which garnered heavy applause from the audience. When men referred to her as Professor Yuan, she immediately corrected them and told them that she was Professor Wu.

In 1975, physics department chairman Serber discovered that Chien-Shiung had a much lower pay than her male colleagues but that she had never reported on it, so he adjusted her pay to make it equal to that of her male counterparts. Chien-Shiung later quipped, "In China there are many, many women in physics. There is a misconception in America that women scientists are all dowdy spinsters. This is the fault of men. In Chinese society, a woman is valued for what she is, and men encourage her to accomplishments, yet she remains eternally feminine.”

Chien-Shiung's advocacies and conviction maintained a strong priority for the advancement of the sciences. Later in 1975 as the first female president of the American Physical Society, she met with President Gerald Ford to formally request him to create an advisory scientific body for the president, which President Ford granted and signed into law the formation of the Office of Science and Technology Policy. She also continued to be an advocate for human rights issues as she protested the crackdown in China that followed the Tiananmen Square massacre of 1989. Chien-Shiung would spend most of her time in her later years visiting China, Taiwan, and different American states. She became renowned for her steadfast promotion of teaching STEM subjects to all students regardless of gender or any other discriminating cause. Her granddaughter, Jada Wu Hanjie, remarked, “I was young when I saw my grandmother, but her modesty, rigorousness and beauty were rooted in my mind. My grandmother had emphasised much enthusiasm for national scientific development and education, which I really admire.”

Wu Chien-Shiung, pen on paper (2021)

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