Yukawa, Hideki (hēˈdĕkē yōkäˈwä) [key], 1907–81, Japanese physicist, grad. Kyoto Univ., 1929, Ph.D. Osaka Univ., 1938. He was professor of physics at Kyoto Univ. from 1939 to 1970. He received the 1949 Nobel Prize in Physics for predicting (1935) the existence of the meson. After further developing the meson theory of nuclear forces, he began (1947) work on his "nonlocal field" theory for elementary particles. In 1948 he came to the United States, where he spent a year at the Institute for Advanced Study and was (1949–53) visiting professor at Columbia.