# Hideki Yukawa

Hideki Yukawa (Japanese: 湯川 秀樹; né Ogawa; 23 January 1907 – 8 September 1981) was a Japanese physicist who received the Nobel Prize in Physics in 1949 for his successful prediction of the existence of the meson.

## Biography

   Physics is a science that has made rapid progress in the twentieth century ... I desire, as I did in the past, to be a traveler in a strange land and a colonist in a new country. (from the foreword to his autobiography)
He was born as Hideki Ogawa in Tokyo and grew up in Kyoto with two older brothers, two older sisters, and two younger brothers. He read the Confucian Doctrine of the Mean, and later Lao-Tzu and Chuang-Tzu. His father, for a time, considered sending him to technical college rather than university since he was "not as outstanding a student as his older brothers". However, when his father broached the idea with his middle school principal, the principal praised his "high potential" in mathematics and offered to adopt Ogawa himself in order to keep him on a scholarly career. At that, his father relented.
Ogawa decided against becoming a mathematician when in high school; his teacher marked his exam answer as incorrect when Ogawa proved a theorem but in a different manner than the teacher expected. He decided against a career in experimental physics in college when he demonstrated clumsiness in glassblowing, a requirement for experiments in spectroscopy.
In 1929, after receiving his bachelor's degree at Kyoto Imperial University, he stayed on as a lecturer for four years. After graduation, he was interested in theoretical physics, particularly in the theory of elementary particles.
In 1932, he married Sumi Yukawa (スミ). In accordance with Japanese customs (see mukoyoshi), since he came from a family with many sons but his father-in-law Genyo had none, he was adopted by Genyo and changed his family name from Ogawa to Yukawa. The couple had two sons, Harumi and Takaaki. In 1933 he became a lecturer at Osaka Imperial University, at 26 years old.
In 1935 he published his theory of mesons, which explained the interaction between protons and neutrons at Osaka Imperial University, and was a major influence on research into elementary particles.
In 1938, he received his Ph.D. degree at Osaka Imperial University for his predictions regarding the existence of mesons and his theoretical work on the nature of nuclear forces. These research achievements were the reason he was later awarded the Nobel Prize in Physics.
In 1940 he became a professor in Kyoto Imperial University. In 1940 he won the Imperial Prize of the Japan Academy, in 1943 the Decoration of Cultural Merit from the Japanese government. In 1949 he became a professor at Columbia University, the same year he received the Nobel Prize in Physics, after the discovery by Cecil Frank Powell, Giuseppe Occhialini and César Lattes of Yukawa's predicted pi meson in 1947. Yukawa also worked on the theory of K-capture, in which a low energy electron is absorbed by the nucleus, after its initial prediction by G. C. Wick.
   [Once I had published my seminal 1934 paper on particle interaction] I felt like a traveler who rests himself at a small tea shop at the top of a mountain slope. At that time I was not thinking about whether there were any more mountains ahead. [conclusion of his autobiography]
Yukawa became the first chairman of Yukawa Institute for Theoretical Physics in 1953. He received a Doctorate, honoris causa, from the University of Paris and honorary memberships in the Royal Society, Royal Society of Edinburgh, the Indian Academy of Sciences, the International Academy of Philosophy and Sciences, the United States National Academy of Sciences, the American Academy of Arts and Sciences, the American Philosophical Society, and the Pontificia Academia Scientiarum.
He was an editor of Progress of Theoretical Physics, and published the books Introduction to Quantum Mechanics (1946) and Introduction to the Theory of Elementary Particles (1948).

## Activism

In 1955, he joined ten other leading scientists and intellectuals in signing the Russell–Einstein Manifesto, calling for nuclear disarmament.
He was one of the signatories of the agreement to convene a convention for drafting a world constitution; subsequently, a World Constituent Assembly convened to draft and adopt a Constitution for the Federation of Earth.

## Retirement and death

Yukawa retired from Kyoto University in 1970 as a Professor Emeritus. Owing to increasing infirmity, in his final years he appeared in public in a wheelchair. He died at his home in Sakyo-ku, Kyoto, on 8 September 1981 from pneumonia and heart failure, aged 74. His tomb is in Higashiyama-ku, Kyoto.
Solo violinist Diana Yukawa (ダイアナ湯川) is a close relative of Hideki Yukawa.

## Recognition

* 1940 – Imperial Prize of the Japan Academy
* 1941 – Academic Noma Award
* 1943 – Order of Culture
* 1949 – Nobel Prize in Physics
* 1963 – Elected a Foreign Member Royal Society (ForMemRS)
* 1964 – Lomonosov Gold Medal
* 1967 – Pour le Mérite
* 1967 – Medal of the Pontifical Academy of Sciences
* 1977 – Grand Cordon of the Order of the Rising Sun
* 1981 – Junior Second Rank (8 September; posthumous)
There is a street, Route Yukawa, named after Yukawa at CERN, Geneva, Switzerland.