Res Wilhelm Jost (born 10.01.1918) is a Swiss theoretical physicist. He was born in Bern. He graduated from the University of Bern (1943). In 1946 — 49 he was an assistant and from 1955 professor at the Zurich Polytechnic (in 1949 — 55 he worked at the Institute for Advanced Study in Princeton).
His research was in the field of mathematical physics, quantum field theory, the physics of elementary particles and quantum electrodynamics. Independently of H. Lehmann and F. Dyson he gave an integral representation for causal commutators (the Jost — Lehmann — Dyson representation), and together with A. Pais he formulated (1952) a selection rule for G-parity. He calculated the radiative corrections for the scattering of a photon by a particle of zero spin. He gave a proof and a generalisation of the CPT theorem and of the universal nature of local commutativity. He introduced (1947) functions that are important in scattering theory (the Jost functions).
A member of a number of academies.