31 March 1906, Tokyo (Japan) - 8 July 1979, Tokyo (Japan)
Tomonaga was born into a wealthy family. From an early age, he received a strong cultural education from his father, Sanjuro Tomonaga, a philosopher and teacher.
After completing his secondary education at the High School in his hometown, Tomonaga entered Kyoto Imperial University in 1926, graduating with a degree in physical science in 1929. There, he coincided with Hediki Yukawa, who was to win the Nobel Prize in Physics in 1949 for formulating the hypothesis of mesons (particles of intermediate mass between the electron and the neutron), based on theoretical work on nuclear forces.
After graduating, he continued his research at Kyoto Imperial University for three years, and in 1931 he moved to the Research Institute of Physics and Chemistry in Tokyo, where he worked under the supervision of Dr. Yoshio Nishina, who introduced him to the world of quantum physics.
In 1937, he began working at the University of Leipzig, collaborating with Werner Heisenberg's research group. Two years later, due to the outbreak of the Second World War, he returned to Japan, where he completed his doctoral thesis on the study of nuclear materials at the University of Tokyo.
From 1940 onwards, he began to study mesons in-depth, which allowed him, between 1942 and 1943, to introduce a series of fundamental corrections in the theory of quantum electrodynamics. While carrying out this work, he began a brilliant teaching career at the University of Bunrika (Tokyo), later absorbed by the University of Tokyo, where Tomonaga continued to teach physics.
In 1948, together with his students, he re-examined a paper by Sidney Dancoff on quantum electrodynamics and discovered the renormalisation method, independently obtaining the same results as Julian Schwinger. The following year Tomonaga was invited by Robert Oppenheimer to work at the Institute for Advanced Study in Princeton Town (New Jersey), where he led a team devoted to the study of another quantum particle, the fermion.
In 1955, back in Japan, Tomonaga became Director of the Nuclear Institute of the University of Tokyo, and a year later he was appointed Rector of the University of Tokyo, a position he held until 1962. Shortly afterward, he was appointed President of the Science Council of Japan by his nation's political authorities, an institution from which he issued numerous proclamations in defence of the peaceful use of nuclear energy. He was also director of the Institute of Optics at the University of Tokyo.
In 1965, together with Julian Seymour Schwinger and Richard Phillips Feynman, he was awarded the Nobel Prize in Physics for his fundamental work in the study of quantum electrodynamics, which led to an in-depth study of the physics of elementary particles.
Además, Tomonaga recibió el Premio de la Academia de las Ciencias de Japón, la Orden de Cultura del Gobierno Japonés y la Medalla Lomonosov, otorgada por las autoridades políticas y culturales de la Unión Soviética. Miembro de la Academia de las Ciencias de Japón, perteneció, además, a otras sociedades científicas internacionales tan prestigiosas como la Academia Leopoldina (Alemania), la Real Academia Sueca de la Ciencia, la Bayerische Akademie der Wissenschaften (Alemania) y la Academia Nacional de la Ciencia de los Estados Unidos de América.
Publicó varios artículos y tratados en los que difundió sus descubrimientos, la mayor parte de ellos relacionados con la dinámica cuántica. Entre sus obras principales, cabe destacar las tituladas Producción fotoeléctrica de electrones positivos y negativos (1934), Formación relativista invariante de la teoría cuántica de los campos de ondas (1946) y, sobre todo, Mecánica cuántica (1962).
