Kazuhiko Nishijima 1926–2009
The eminent physicist and former director of the Yukawa Institute for Theoretical Physics, Kazuhiko Nishijima, passed away on 15 February. He had been ill for the past year.
Nishijima is well known for his contributions to particle physics. His study of the physics of strange particles and introduction of the quantum number "strangeness" was a decisive step in the development of particle physics. His work played a crucial role in subsequent developments of the quark model and flavour symmetry in particle physics.
He is also well known for his work on the two-component theory of neutrinos, and the axiomatic formulation of bound states in quantum field theory. His interpretation of renormalization in field theory from the point of view of dispersion relations has also been highly influential.
Nishijima had positions at the University of Illinois (1961–6) and the University of Tokyo (1966–86) before becoming director of the Yukawa Institute of Theoretical Physics at Kyoto University in 1986–70. During his directorship at the Yukawa Institute he arranged its unification with the Institute of Theoretical Physics of Hiroshima University. He became a member of the Japan Academy in 1989 and received the order of culture, the highest honour of cultural achievements in Japan, in 2003. We offer our sincere condolences to his family.
Tohru Eguchi, director, Yukawa Institute for Theoretical Physics, Kyoto University.