Sir William Lawrence Bragg CH OBE MC FRS was born on this date in 1890. He was an Australian-born British physicist and X-ray crystallographer, discoverer (1912) of the Bragg law of X-ray diffraction, which is basic for the determination of crystal structure. He was a joint winner (with his father, Sir William Henry Bragg) of the Nobel Prize in Physics in 1915: “For their services in the analysis of crystal structure by means of X-ray.” This was an important step in the development of X-ray crystallography. He was knighted in 1941. To date, Lawrence Bragg is the youngest Nobel Laureate, having received the award at the age of 25. He was the director of the Cavendish Laboratory, Cambridge, when the discovery of the structure of DNA was reported by James D. Watson and Francis Crick in February 1953.
Hans Fischer died on this date 1945. He was a German organic chemist and the recipient of the 1930 Nobel Prize in Chemistry. Sin’ichirō Tomonaga was born on this date in 1906. He was a Japanese physicist, influential in the development of quantum electrodynamics for which he was jointly awarded the Nobel Prize in Physics in 1965 along with Richard Feynman and Julian Schwinger.Born in Tokyo, 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 Prize winner, was one of his classmates during undergraduate school. During graduate school at the same university, he worked for three years as a lab assistant. After graduate school, he joined Nishina’s group in Riken. In 1937, while working at Leipzig University, he collaborated with the Werner Heisenberg research group. Two years later, he returned to Japan due to the outbreak of the Second World War, but finished his doctoral degree in the study of nuclear materials with his thesis extending work done while in Leipzig.In Japan, he was appointed to a professorship at the Tokyo University of Education. During the war, he studied the magnetron, meson theory, and his “super-many-time” theory. In 1931, he became a researcher in Yoshio Nishina’s laboratory at RIKEN. 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 QED can be cancelled 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 the next year, he was invited by Robert Oppenheimer to work at the Institute for Advanced Study in Princeton. He studied a many-body problem on the collective oscillations of a quantum-mechanical system. In the following year, he returned to Japan and proposed the Tomonaga-Luttinger liquid. In 1965, he was awarded the Nobel Prize in Physics, with Julian Schwinger and Richard P. Feynman, for the study of QED, specifically for the discovery of the renormalization method. He died of throat cancer in Tokyo in 1979.He was awarded the Order of Culture in 1952 and the Grand Cordon of the Order of the Rising Sun in 1976.