Archive of historical materials
Letter from Shin-ichiro Tomonaga to Yukawa (1933)
OU1934-B5 (14 pages) Date: Not indicated
This letter was written on the front and back sides of seven sheets of paper. The letter was a reply to the letter and research paper that Yukawa sent to Shin-ichiro Tomonaga. It was probably sent in early 1933. The back side (page 2) of the first sheet contains Yukawa’s hand calculations. Yukawa became a lecturer (additional post) in the School of Science, Osaka Imperial University in 1933, and then took a position of full-time lecturer the following year in 1934.
During this period, Yukawa and Tomonaga concentrated on elucidating nuclear forces day in and day out, and communicated their thoughts to each other. In this letter, before starting the explanation, Tomonaga wrote “I am presently working on calculations and I believe that the ongoing process is not very interesting, so I omit details.” While analyzing the Heisenberg theory of interactions between neutrons and protons, Tomonaga attempted to explain the mass defects of deuterium by using the hypothesis that is now known as Yukawa potential. The determination of potential was arbitrary and the latest Pegrum’s experiment at that time was taken into consideration. Tomonaga also compared his results with Wigner’s theorem and Majorana’s theory.
In the last page of the letter, he wrote “I am happy to hear that you will move to Osaka and continue your research there. Since the university is newly established, I reckon the place is full of vitality and stimulations. It would be great if Dr. Kikuchi and others join you there.” Yukawa and Tomonaga’s close colleagues anticipated that Osaka Imperial University and RIKEN would be the Japan’s frontier centers for quantum physics. (Written by Yutaka Hosotani)
