Ishihara Jun

Ishihara Jun ( Japanese 石 原 純 , Ishiwara / Ishihara Atsushi / Jun ; born January 15, 1881 in Tokyo , † January 19, 1947 in Chiba Prefecture) was a Japanese theoretical physicist .

Ishihara was a son of a Christian clergyman (Ryo Ishiwara). He was a student of Nagaoka Hantarō at the University of Tokyo, where he graduated in 1906 and studied for two years before he became a teacher at the artillery and pioneer school in 1908. In 1911 he became an assistant professor at the Imperial University of Tokyo. He studied from April 1912 to May 1914 among others with Max Planck in Berlin and then with Arnold Sommerfeld in Munich, visited Albert Einstein in Zurich in 1913 and received in 1914 a full professor of physics at the newly founded University of Tōhoku .

Ishihara was one of the first important Japanese theoretical physicists and dealt with, among other things, quantum theory, nuclear physics and relativity theory. He met Einstein in Berlin in 1912 and accompanied him on his Japan lecture tour in 1922, among other things as an interpreter. He is co-author of a Japanese dictionary of physics and chemistry. Due to a love affair, he had to end his university career in 1921 and switched to writing. He edited four volumes of Einstein's collected works in Japanese translation and wrote popular science works.

Pyenson mentions it as an example for gifted physicists in the early days of modern physics in the 20th century, who were hampered in their effectiveness by the fact that they came from the scientific periphery. He dealt with electron theory of metals, (older) quantum theory and special and general relativity theory. In the theory of relativity, he dealt with the principle of smallest action and thus derived the energy-momentum tensor independently of Hermann Minkowski . This work also caught the attention of Einstein. He developed his own theory of gravity at the time when Einstein was also developing his general theory of relativity. He himself wanted to loosen the principle of the constancy of the speed of light c by making the time scale variable and only the product c dt constant. He later developed a five-dimensional theory that was supposed to combine gravity and electrodynamics. In 1915 he introduced a quantization of the phase space.

He was also a moralist and poet, and wrote waka and tanka poems and was one of the authors of Araragi magazine . Before World War II, he wrote essays criticizing state control over science.

In 1919 he received the prize of the Imperial Academy of Sciences for his physical work on quantum and relativity theory.

literature

• Tetu Hirosige, Article in Dictionary of Scientific Biography

Fonts

• On the principle of the smallest effect in electrodynamics of moving ponderable bodies, Annalen der Physik, Series 6, Volume 42, 1913, 986–1000
• On the relativistic theory of gravitation, Science Reports of Tohoku Imperial University, Volume 4, 1915, 111-160
• Universal meaning of the quantum of action, Proceedings of the Mathematico-physical Society, Volume 8, 1915, pp. 106-116
• Sōtaisei Genri (Principle of Relativity), Tokyo 1921

Individual evidence

1. ↑ He co-wrote Einstein's lecture How I created the theory of relativity in Kyoto 1922 and published it in Japanese in the newspaper Kaizo 1923, republished as Einstein Ko-en Roku , Tokyo-Toshu, Tokyo 1971, English translation by Ono in Physics Today, August 1982
2. ^ Review of Friedrich Hund's History of Quantum Theory , Historia Mathematica, Volume 2, 1975, p. 371

Japanese name: As is common in Japan, the family name comes before the first name in this article . So Ishihara is the family name, Jun is the first name.