Feedback: One physicist started it all

This is an English translation of a "Readers digest" which I published in the Swedish popular science journal "Forskning och Framsteg" (F&F, in English: Research and Progress) in 2009 (F&F 2/2009; in Swedish). It was written as a reflection on a side-line of a previous article in F&F about the four Japanese Nobel prize winners in 2008 with the title "Nothing is perfect" (Ingenting är perfekt). The side-line is called "The Japanese wonder".

Japan's scientific development which, among others, led to four Nobel prizes last fall, could have hardly been possible without the country's first great scientist of international dimensions, the physicist Yoshio Nishina (1890-1951). However, he is only mentioned indirectly in F&F's chronicle.

Nishina worked in Niels Bohrs institute in Copenhagen during the years 1921-28, an unusually long stay in a foreign land for a Japanese at that time. The visit took place while the new quantum mechanics took shape. Towards the end of his visit Nishina derived, together with the Swedish physicist Oskar Klein, a quantum mechanical formula for the scattering of photons on electrons. This came to be the famous Klein-Nishina formula, which even today is the standard tool in the calculations for e.g. radiation protection.

After returning back to Japan in 1928, he built up modern physics research in Japan with many young researchers, and he established contact with overseas research in the west. He invited several of the world's most prominent researchers to Japan, e.g. Paul Dirac, Werner Heisenberg and Niels Bohr, all three being Nobel Laureates in physics. Their lectures inspired the young Japanese physicists enormously.

To his research in nuclear physics, he built a gigantic Wilson chamber, and later two cyclotrons. With these equipment he positioned himself at the frontline of international research. Among others, he could have received the Nobel prize for his discovery of the meson in a measurement with the Wilson chamber. Due to a misunderstanding, his publication of the discovery got delayed, and during the delay other competing groups managed to publish their results. On the other hand two of his students received the Nobel prize: Hideki Yukawa (1949) for his meson theory, and Sin-Ichiro Tomonaga (1965) for quantum electrodynamics. Yukawa was the very first Japanese Nobel prize winner ever.

During WW2 Nishina was ordered to work on Japan's atomic bomb project, but as it was mentioned in the article in F&F, the project did not get especially far with the meager resources he had access to. When the bombs were dropped on Hiroshima and Nagasaki was he ordered by the military to visit both places, to confirm whether it was indeed atomic bombs that were dropped. He collected a large number of samples, and the visit probably contributed to the fact that a few years later he died in an aggressive lever cancer.

Despite protests from the international scientific community, straight after the war Nishina had to witness that the American War Department dumped both of his cyclotrons in the deep waters of the Bay of Tokyo, because they suspected (erroneously) that they could be used to generate material for nuclear weapons.

In 2004, together with Kojiro Nishina, the son of Yoshio Nishina and just like his father, himself a professor in physics, and article in the annual booklet "Kosmos" of the Swedish Physical Society:

Yoshio Nishina and the birth of modern physics in Japan.

Imre Pázsit
Professor in Nuclear Engineering
Chalmers University of Technology