Shin'ichiro Tomonaga

Shin'ichirō Tomonaga was a Japanese physicist who made significant contributions to the development of quantum electrodynamics, the theory that describes the interactions of light and matter. He was awarded the Nobel Prize in Physics in 1965, along with Richard Feynman and Julian Schwinger, for his work on renormalization, a method of dealing with the infinities that arise in quantum field theory. Tomonaga was born in Tokyo in 1906, the son of a philosopher. He studied physics at Kyoto Imperial University, where he was a classmate of Hideki Yukawa, another Nobel laureate. He obtained his PhD in 1939 and became a professor at Bunrika University (later Tokyo University of Education). During World War II, he worked on the Japanese atomic bomb project, but also continued his research on quantum electrodynamics. He developed the idea of covariant perturbation theory, which allowed him to formulate the renormalization procedure independently of Feynman and Schwinger. He also introduced the concept of Tomonaga–Luttinger liquid, a model of interacting electrons in one dimension. After the war, he visited the Institute for Advanced Study in Princeton, where he met Albert Einstein and other prominent physicists. He became the president of Tokyo University of Education in 1956 and the president of the Science Council of Japan in 1963. He received many honors and awards, including the Asahi Prize, the Lomonosov Gold Medal, and the Order of Culture. He died of cancer in Tokyo in 1979, at the age of 73. He was survived by his wife and three daughters.