Walter Eduard Thirring (born 29.04.1927) was an Austrian theoretical physicist and a member of the Austrian Academy of Sciences. He was born in Vienna. He graduated from the University of Vienna (1949). In 1952-59 he worked at the University of Berne (professor from 1958). From 1959 he was professor at the University of Vienna and director of the Institute of Theoretical Physics.
His research was in the fields of quantum electrodynamics, quantum field theory, elementary-particle physics, the theory of gravitation and solid-state physics. Together with M. Goldberger he studied the scattering of mesons by nucleons in the limiting case of low meson energy, and with M. Gell-Mann and Goldberger he developed (1954) the method of dispersion relations in quantum field theory. He considered the Compton scattering of photons of very low energy by an electron in order to clarify the meaning of charge renormalisation in quantum electrodynamics. He studied the convergence of the S-matrix for scattering processes (1953) and proved the divergence of the perturbation expansion in the case of scalar meson theory with a nonlinear perturbation.