Born: 31 March 1906, Kyoto, Japan
Died: 8 July 1979, Tokyo, Japan
Affiliation at the time of the award: Tokyo University of Education, Tokyo, Japan
Prize motivation: "for their fundamental work in quantum electrodynamics, with deep-ploughing consequences for the physics of elementary particles"
Field: quantum electrodynamics, quantum mechanics
Prize share: 1/3
Following the successes of the theory of relativity and quantum mechanics, a first relativistic theory was formulated for the interaction of charged particles with electromagnetic fields. However, partly because of the so called Lamb shift observed in 1947 in hydrogen, where two energy levels that were supposed to have the same energy instead was shown to have a small difference in energy, the theory must be reformulated. Sin-Itiro Tomonga solved this problem 1948 by so called renormalization and consequently contributed to a new quantum electrodynamics.