Ryogo Kubo (born 15.02.1920) is a Japanese theoretical physicist. He graduated from the University of Tokyo (1941), where he has worked ever since (professor from 1954).
His research concerned mainly the quantum theory of magnetism and the statistical theory of irreversible processes. In 1957 he developed a general statistical-mechanical method of calculating thermodynamic equilibrium and kinetic coefficients (the Kubo method). Independently of M. Green he developed the formalism of the statistical thermodynamics of irreversible processes, and independently of L. Van Hove he was the first to begin (1955) research on the quantum theory of irreversible processes. He carried out (1963) a general calculation of spin fluctuations, including critical ones.
In 1964-65 he was president of the Physical Society of Japan. An honorary member of a number of academies of sciences and scientific societies. The Y. Nishina (1957), Japan Academy (1969) and L. Boltzmann (1977) Prizes.