Tsung-Dao Lee is a Chinese-American physicist and Nobel Laureate in Physics

Tsung-Dao Lee (November 24, 1926 – August 4, 2024) was a Chinese-American physicist known for his achievements in cosmic non-conservation, Lee Model, relativistic heavy ion (RHIC) physics, and non-topological soliton and soliton stars in quantum field theory. He was Professor Emeritus at the University of Colombia, lecturing from 1953 to 2012.

In 1957, 31-year-old Tsung-Dao Lee and fellow Chinese physicist Yang Chen-ning were awarded the Nobel Prize in Physics for their discovery of non-conservation of universal symmetry under weak action, a theory confirmed by experiments by another Chinese physicist, Chien-shiung Wu.

Lee was the youngest Nobel laureate since World War II, a record that was not broken until Malala · won the 2014 Nobel Peace Prize. He is also the fourth-youngest Nobel laureate in history, behind William · Lawrence· Prague (25, 1915), Werner· Heisenberg (30, 1932) and Malala (17, 2014). Lee Tsung-Dao and Yang Zhenning were the first two Chinese Nobel laureates. Even after naturalizing as a United States citizen in 1962, Lee was the youngest United States Nobel laureate.

Life

Tsung-Dao Lee was born in Shanghai, Republic of China in 1926, his ancestral home is Suzhou, Jiangsu, his father Li Junkang was the first graduate of the Department of Agrochemistry of Jinling University, and his grandfather Li Zhongqin (1870-1941) was the first Chinese senior pastor (rectory) of St. John's Church in Suzhou. Li Zhengdao studied at the Affiliated High School of Soochow University in Suzhou and Xiuzhou Middle School in Jiaxing during the Anti-Japanese War. Ganxian Christian United Middle School (referred to as Ganzhou United High School) established by moving to Ganxian County, Jiangxi Province, but did not graduate from middle school due to the Anti-Japanese War. In 1943, he was admitted to the Department of Physics of Zhejiang University, which moved to Guizhou, with the same academic ability in Guiyang, and embarked on the road of physics, under the supervision of Shu Xingbei and Wang Ganchang. In 1944, the Japanese army entered Guizhou, and Zhejiang University was suspended. In 1945, he transferred to Southwest Associated University in Kunming as a second-year student, under the tutelage of Wu Dayou and Ye Qisun. Wu Dayou commented on Li Zhengdao when he was studying at Southwest Associated University, saying: "Every day he comes to my place and asks me to give him more reading materials and exercises, and his curiosity is really strange to the point", "No matter how difficult the books and topics I give him, he will finish them quickly, and he will come to ask for more." ”

After the end of the Anti-Japanese War, the Southwest Associated University was suspended, and Lee Tsung-dao did not graduate. Later, under the recommendation of his mentor Wu Dayou, he went to the United States in 1946 to enter the University of Chicago under the tutelage of Enrico · Fermi. After receiving his Ph.D. in 1950, he worked with his collaborators on phase transitions in statistical physics and polarons in condensate physics. In 1953, he became an assistant professor at the University of Colombia, where his research was in the field of particle physics and field theory. In October 1956, 30-year-old Li Zhengdao and 34-year-old Yang Zhenning published an article in the United States Physical Review, proposing that the universe is not conserved in weak interactions, and won the Nobel Prize in physics in 1957. In 1958, Lee Tsung-dao was elected as the second academician of the Academia Sinica at the age of 32, and he is still the youngest academician to be elected.

Lee became a United States citizen in 1962. Since the early 1970s, he and his wife, Qin Huixuan, began to visit Chinese mainland. He suggested to the relevant parties that attention should be paid to the cultivation of scientific and technological talents and basic scientific research: to promote cooperation between China and the United States in high-energy physics, and to suggest and assist in the establishment of the Beijing Positron Collider; proposed the establishment of a Natural Science Foundation; In the 1980s, the CUSPEA examination was established to provide scholarships for outstanding undergraduate graduates to pursue a Ph.D. in physics in the United States. It is recommended to establish a postdoctoral system.

In October 1972, Lee returned to China and was received by Zhou Enlai, Premier of the State Council of the People's Republic of China. In 1974, Lee returned to China and was received by Mao Zedong, chairman of the Central Committee of the Communist Party of China. During the meeting, Lee Tsung-dao suggested that Mao Zedong should refer to the model of Chinese sports for athletes to be trained from an early age, and set up a university junior class to scientifically cultivate China's young talents. Mao Zedong nodded in agreement, and soon after, China's first junior class was established at the University of Science and Technology of China.

On November 29, 1996, Lee Tsung-dao's wife, Qin Huiyan, passed away from lung cancer. In 1997, Lee Tsung-Dao and his relatives and friends donated $300,000 to the "Qin Hui-yin and Lee Tsung-Dao Chinese College Student Internship and Training Fund", referred to as the Cheng Cheng Fund. The Foundation now supports outstanding university students from six universities, including Peking University, Shanghai Jiao Tong University, Fudan University, Soochow University, Lanzhou University and National Tsinghua University, to conduct basic scientific research.

The cosmic symmetry is not conserved under weak action

Cosmology is a quantum mechanical quantity. In quantum mechanics, particles are represented by a wave function. Under spatial inversion (x → -x, y → -y, z → -z), if the wave function is unchanged, the cosmic symmetry of the particle is positive, and if the transformed wave function is one negative sign away from the original wave function, the cosmic symmetry of the particle is negative. Spatial inversion invariance can also be called mirror invariant, or left-right invariant, because spatial inversion is only one 180-degree rotation about the x-axis from the mirror transformation or left-right transformation (x → -x, y → y, z → z). And rotational invariance is strictly established, so there is no essential difference between the two. The universe scale can only take two values, 1 and -1. The total symmetry of a system consisting of two or more particles is equal to the product of the cosmic symmetry of each particle in the system, multiplied by the orbital cosmetry. The law of conservation of cosmic symmetry refers to the fact that under interaction, the total cosmic symmetry of the particle system after action is equal to the total cosmic symmetry of the particle system before the interaction. Before 1956, it was accepted in the physics community that the universe was conserved under any kind of interaction. The conservation of cosmic symmetry essentially means that the left and right are symmetrical.

In the early 50s, two new particles, θ and τ, were observed from cosmic rays. θ decays into two π mesons, and τ decays into three π mesons. The cosmic symmetry of the π meson is negative, and the orbital symmetry of both systems before and after decay is positive, according to the Dalitz diagram. Since the symmetrical product of even-numbered π mesons is positive, while the product of the odd π mesons is negative, we can inversely extrapolate that the symmetry of θ is positive and the symmetry of τ is negative. Whereas, θ and τ have exactly the same lifetime and mass. Are θ and τ different particles, or the same particle? This was the famous θ-τ mystery that puzzled the physics community back then. How to solve this mystery? There are only two answers. One acknowledges the law of conservation of universal symmetry that τ and θ are two different particles, but this does not answer why the properties of theta and τ particles are so identical. Another affirmation that τ and θ are the same kind of particle means that the law of conservation of universal symmetry will not hold.

In 1956, Tsung-Dao Lee and Chen-Ning Yang published the famous article "Questioning the Conservation of Cosmic Symmetry in Weak Interactions". In this article, they argue that the problem of cosmic non-conservation caused by the θ-τ mystery is not an isolated event, and that cosmic non-conservation is likely to be a universal basic scientific principle. At the same time, they found that in the field of strong interactions, the law of conservation of cosmic symmetry has been rigorously proven, but in the field of weak interaction, although the assumption of conservation of cosmic symmetry is widely used, in fact, the law of conservation of cosmic symmetry has never been verified by real experiments.

To measure the symmetry correctly, it is necessary to combine a new pseudoscalar that can be produced by weak action. With this pseudoscalar, it is possible to test whether the symmetry is conserved. And these pseudoscalars have never been measured by any previous experiment. They believe that the solution to the τ-θ riddle must be found outside τ-θ. If the conservation of universal symmetry is broken, then this disruption should also be observed in other experiments with weak effects, for example, in the process of β decay of polarized nuclei. The experimental setup is strictly set to mirror each other, and then the pseudoscalar <σ·p > values during the decay process of the β under different polarizations are measured separately, where p is the momentum of the electron and σ is the spin of the nucleus. If the measurements are different, it is confirmed that the symmetry is not conserved.

At their suggestion, Wu Chien-shiung and United States National Bureau of Standards scientist E. Ambera Ambler) and others to verify their conjectures with concise and clear experiments. This is an experiment on the decay β polarized cobalt-60 nuclei. In this experiment, they showed with conclusive evidence that the law of conservation of cosmic symmetry does not hold during weak interactions. The discovery and experimental verification of the non-conservation of cosmic symmetry under weak interaction was an extremely important discovery after the Second World War. It was for this outstanding contribution that shocked the physics community that Lee Tsung-dao and Yang Chen-ning jointly won the 1957 Nobel Prize in Physics.

Tsung-Dao Lee's great-grandfather, Li Ziyi, was one of the founders of Suzhou Boxi Academy, the predecessor of Soochow University (now Soochow University) in Jiangsu. Lee's grandfather was a provost at Soochow University for decades, and his uncle also served at Boxi Hospital and Soochow University for decades.

Lee and Yang began a close and fruitful collaboration in the late 1940s, with a total of 32 papers published, but this collaboration ended in the early 1960s. Since then, the two have parted ways, which has become a regrettable affair for the Chinese academic community. As for the reasons for the split in their personal relationship, Li and Yang occasionally publicly stated, but each had its own explanation, so that the outside world still does not know the real reason.

In his 1986 essay "The Broken Universe", Lee Tsung-dao has a vivid analogy for the relationship between Li and Yang: "One dark and foggy day, two children were playing on the beach, and one of them said, 'Hey, do you see that flickering light?' The other replied: 'See, let's take a closer look.' The two children were so curious that they ran shoulder to shoulder towards the light. Sometimes one is in front, sometimes the other is in front.

Like a race, they do their best and run faster and faster. Their effort and speed made the two of them so excited that they forgot everything. The first child to arrive at the door said: 'Found it!' He opened the door. The other rushed in, dazzled by the extraordinary beauty inside, and exclaimed, 'How wonderful! How splendid! As a result, they discovered the treasury of the Yellow Empire. This merit of theirs has led them to receive a great award and is the envy of the people. They are famous all over the world. As many years passed, they grew old and became quarrelsome. Memories are blurry, life is monotonous. One of them decided to engrave his epitaph in gold: 'Here rests the man who first discovered the treasure.' The other then said: 'But it was I who opened the door.' ’”

In addition, Lee said: "My cooperation with Yang ended more than 20 years ago. Its value, which needs no more explanation, stands the test of time, as shown by the scientific papers we have published. Lee also mentioned in 2003 that the two had disagreed views on who discovered that the universe was not conserved.

Family

· Wife Qin Huijun (1925-1996): On Christmas Day 1948, Lee Tsung-dao went to the train station to pick up his friend Ling Ning's sister Ling Nancy. arrived in Chicago with Nancy for a vacation, and there was also a slender and dignified and beautiful girl Qin Huixuan. Lee Tsung-do fell in love at first sight and wrote a letter to court. The couple has 2 sons;

· The eldest son, James Lee (1952-), received a bachelor's degree in history from Yale University in United States in 1974; He received a master's degree in history from the University of Chicago in United States in 1975. He received his Ph.D. in History from the University of Chicago in United States in 1983. He has been a professor at the California Institute of Technology; Frederick Heutwell Professor of History and Sociology, University of Michigan; Research Professor, Center for Population Research, University of Michigan; Fellow, Intercollegiate Association for Political and Social Studies, University of Michigan; Director of the Institute of Chinese Studies, University of Michigan; Peking University-University of Michigan College Co-Dean; Changjiang Scholar Chair Professor, Peking University; He is currently the Dean of the School of Humanities and Social Sciences at the Hong Kong University of Science and Technology and a Visiting Chair Professor at Shanghai Jiao Tong University.

· Stephen Lee (born November 24, 1956) received his B.A. from Yale University in 1978 and his Ph.D. from the University of Chicago in 1985. He then taught at the University of Michigan and became an assistant professor in 1993. He was awarded the MacArthur Fellowship in 1994. In 1995, he went to Cornell University as a visiting scholar. He joined Cornell University in 1999 as a tenured professor in the Department of Chemistry and Chemical Biology.

honor

· 1957: Nobel Prize in Physics

· 1969: Medal of the G. Bude of the National Academy of France

· 1977: Medal of the G. Bude of the National Academy of France

· 1979: Galileo Medal

· 1994: Peace Science Prize

· 1995: People's Republic of China International Science and Technology Cooperation Award

· 1997: Named asteroid 3443 as Lee Tsung-do

· 1997: New York City Science Prize

· 1999: Pope John Paul Medal

· 1999: Medal of the Ministry of the Interior of the Government of Italy

· 2000: New York Academy of Sciences Prize