Ruelle–Taylor resonances of Anosov actions

Abstract

Combining microlocal methods and a cohomological theory developed by J. Taylor, we define for Anosov ${\mathbb{R}}^{\kappa }$-actions a notion of joint Ruelle resonance spectrum. We prove that these Ruelle–Taylor resonances fit into a Fredholm theory, are intrinsic and form a discrete subset of ${\mathbb{C}}^{\kappa }$, with $\lambda =0$ being always a leading resonance. The joint resonant states at $0$ give rise to some new measures of SRB type and the mixing properties of these measures are related to the existence of purely imaginary resonances. The spectral theory developed in this article applies in particular to the case of Weyl chamber flows and provides a new way to study such flows.