Ruelle studied physics at the
Free University of Brussels, obtaining a PhD degree in 1959 under the supervision of
Res Jost. He spent two years (1960–1962) at the
ETH Zurich, and another two years (1962–1964) at the
Institute for Advanced Study in
Princeton, New Jersey. In 1964, he became professor at the
Institut des Hautes Études Scientifiques in
Bures-sur-Yvette,
France. Since 2000, he has been an
emeritus professor at IHES and distinguished visiting professor at
Rutgers University. David Ruelle made fundamental contributions in various aspects of mathematical physics. In quantum field theory, the most important contribution is the rigorous formulation of
scattering processes based on
Wightman's axiomatic theory. This approach is known as the
Haag–Ruelle scattering theory. Later Ruelle helped to create a rigorous theory of
statistical mechanics of equilibrium, that includes the study of the
thermodynamic limit, the equivalence of
ensembles, and the convergence of Mayer's series. A further result is the Asano-Ruelle lemma, which allows the study of the zeros of certain polynomial functions that are recurrent in statistical mechanics. The study of infinite systems led to the local definition of
Gibbs states or to the global definition of
equilibrium states. Ruelle demonstrated with
Roland L. Dobrushin and
Oscar E. Lanford that translationally invariant Gibbs states are precisely the equilibrium states. Together with
Floris Takens, he proposed the description of hydrodynamic
turbulence based on strange attractors with chaotic properties of hyperbolic dynamics. == Honors and awards ==