Tsung-Dao Lee Biography

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Tsung-Dao Lee was born in Shanghai, China, on November 24, 1926. He was the third of six children born to Tsing-Kong Lee, a businessman, and Ming-Chang Chang. Lee attended the Kiangsi Middle School in Kanchow and, after graduation, entered the National Chekian University in Kweichow. After the invasion of Japanese troops in 1945, Lee fled to the south, where he continued his studies at the National Southwest Associated University in Kunming.

In 1946, Lee was presented with an unusual opportunity. One of his teachers at Kunming was the theoretical physicist Ta-You Wu. When Wu decided to return to the United States (where he had worked toward his Ph.D. degree), he invited Lee to accompany him. Lee accepted the offer and subsequently enrolled at the University of Chicago, the only American university that would accept him for graduate study without an undergraduate degree.

At Chicago, Lee selected a topic in astrophysics for his doctoral research. Working under physicist Enrico Fermi, he completed that research and was awarded his Ph.D. in 1950 for his dissertation, on the hydrogen content of white dwarf stars. While at Chicago, Lee also renewed his friendship with physicist Chen Ning Yang. Lee and Yang had been acquaintances at Kunming. They were separated in 1950 when Lee went to the Yerkes Astronomical Observatory at Lake Geneva, Wisconsin, and Yang went to the Institute for Advanced Studies at Princeton University. Lee then spent the next year (1950-51) as a research associate at the University of California at Berkeley. The two friends were reunited in 1951, however, when Lee accepted an appointment at the Institute for Advanced Studies.

Lee's departure from Princeton in 1953 for a post as assistant professor of physics at Columbia University seems to have had little effect on his collaboration with Yang. By the spring of 1956, they had begun to focus on a particularly interesting subject, a subatomic particle known as the K-meson. Discovered only a few years earlier, the K-meson puzzled physicists because it appeared to be a single particle that decayed in two different ways. The decay schemes were so different that physicists had become convinced that two distinct forms of the K-meson existed, forms they called the tau meson and theta meson.

The single difference between these two mesons was that one form had even parity and the other form had odd parity. The term parity refers to the theory that the laws of nature are not biased in any particular direction. That is, if one has two sets of interactions that are mirror images of each other, the physical laws describing those interactions are identical. This concept is known as the conservation of parity.

The problem that Lee and Yang attacked was that vast amounts of experimental evidence suggested that the theta and tau mesons were one and the same particle. The only contrary evidence was that the two mesons had opposite parity and, therefore, supposedly could not be identical. During an intense three-week period of work in the spring of 1956, Lee and Yang solved this puzzle. Their solution was to suggest, simply enough, that in some types of reactions, parity is not conserved. The beta decay of the (one and only) K-meson was such a reaction. They then devised a series of experiments by which their theory could be tested.

About six months later, the experiments suggested by Lee and Yang were carried out by one of their colleagues, Chien-Shiung Wu, first at Columbia and then at the National Bureau of Standards. The experiments confirmed the Lee-Yang prediction in every respect. Less than a year later, the two theorists were awarded the 1957 Nobel Prize in physics for their work.

After promotions to associate professor (1955) and professor (1956) at Columbia, Lee returned to the Institute for Advanced Studies in 1960 for three years. He then was appointed Enrico Fermi Professor of Physics at Columbia in 1963. In 1984, he was made University Professor at Columbia. Beginning in 1981, Lee held appointments as honorary professor at a number of Chinese universities, including the University of Science and Technology (1981), Jinan University (1982), Fudan University (1982), Quinghua University (1984), Peking University (1985), Nanjing University (1985), and Zhejiang University (1988). He married Hui-Chung Chin (also known as Jeanette) on June 3, 1950, while they were both students at Chicago. The Lees have two sons.