Shinichiro Tomonaga

, usually cited as Sin-Itiro Tomonaga in English, was a Japanese physicist. He shared the 1965 Nobel Prize in Physics with Richard Feynman and Julian Schwinger "for their fundamental work in quantum electrodynamics (QED), with deep-ploughing consequences for the physics of elementary particles".

Biography Tomonaga was born in Tokyo in 1906. He was the second child and eldest son of a Japanese philosopher, Tomonaga Sanjūrō. He entered the Kyoto Imperial University in 1926. Hideki Yukawa, also a Nobel laureate, was one of his classmates during undergraduate school. During graduate school at the same university, he worked as an assistant in the university for three years. In 1931, after graduate school, he joined Nishina's group in RIKEN. In 1937, while working at Leipzig University (Leipzig), he collaborated with the research group of Werner Heisenberg. Two years later, he returned to Japan due to the outbreak of the Second World War, but finished his doctoral degree (Dissertation PhD from University of Tokyo) on the study of nuclear materials with his thesis on work he had done while in Leipzig.

In Japan, he was appointed to a professorship in the Tokyo University of Education (a forerunner of Tsukuba University). During the war he studied the magnetron, meson theory, and his super-many-time theory. In 1948, he and his students re-examined a 1939 paper by Sidney Dancoff that attempted, but failed, to show that the infinite quantities that arise in quantum electrodynamics (QED) can be canceled with each other. Tomonaga applied his super-many-time theory and a relativistic method based on the non-relativistic method of Wolfgang Pauli and Fierz to greatly speed up and clarify the calculations. Then he and his students found that Dancoff had overlooked one term in the perturbation series. With this term, the theory gave finite results; thus Tomonaga discovered the renormalization method independently of Julian Schwinger and calculated physical quantities such as the Lamb shift at the same time.

In 1949,

Recognition 1946 – Asahi Prize 1948 – Japan Academy Prize 1951 – Member of the Japan Academy

1964 – Lomonosov Gold Medal 1965 – Nobel Prize in Physics 1965 – elected to the United States National Academy of Sciences 1966 – elected to the American Philosophical Society

1975 – elected to the American Academy of Arts and Sciences

Selected publications Books

Articles

Tomonaga, S. "On a Relativistically Invariant Formulation of the Quantum Theory of Wave Fields." Prog. Theor. Phys. 1, 27–42 (1946). Koba, Z., Tati, T. and Tomonaga, S. "On a Relativistically Invariant Formulation of the Quantum Theory of Wave Fields. II." Prog. Theor. Phys. 2, 101–116 (1947). Koba, Z., Tati, T. and Tomonaga, S. "On a Relativistically Invariant Formulation of the Quantum Theory of Wave Fields. III." Prog. Theor. Phys. 2, 198–208 (1947). Kanesawa, S. and Tomonaga, S. "On a Relativistically Invariant Formulation of the Quantum Theory of Wave Fields. IV." Prog. Theor. Phys. 3, 1–13 (1948). Kanesawa, S. and Tomonaga, S. "On a Relativistically Invariant Formulation of the Quantum Theory of Wave Fields. V." Prog. Theor. Phys. 3, 101–113 (1948). Koba, Z. and Tomonaga, S. "On Radiation Reactions in Collision Processes. I." Prog. Theor. Phys. 3, 290–303 (1948). Tomonaga, S. and Oppenheimer, J. R. "On Infinite Field Reactions in Quantum Field Theory." Phys. Rev. 74, 224–225 (1948).