Rigidity of equilibrium states and unique quasi-ergodicity for horocyclic foliations
Pablo D. Carrasco, Federico Rodriguez-Hertz
TL;DR
The paper establishes a rigidity result for equilibrium states of topologically mixing metric Anosov flows with Hölder potentials, showing that such states are completely determined by their disintegration along unstable leaves and a transverse quasi-invariant structure. It develops a symbolic-model framework and Marcus-type averaging operators to transfer the problem to a shift system, proving convergence of averaging operators to constants and obtaining a unique equilibrium state from the unstable conditional data. This leads to unique quasi-ergodicity of horocyclic foliations under a Hölder Jacobian and provides an analytic, non-differential proof of Babillot-Ledrappier's result. The work connects transfer-operator methods with foliation holonomy and offers a broader perspective on rigidity phenomena beyond one-dimensional unstable distributions.
Abstract
In this paper we prove that for topologically mixing metric Anosov flows their equilibrium states corresponding to Hölder potentials satisfy a strong rigidity property: they are determined only by their disintegrations on (strong) stable or unstable leaves. As a consequence we deduce: the corresponding horocyclic foliations of such systems are uniquely quasi-ergodic, provided that the corresponding Jacobian is Hölder, without any restriction on the dimension of the invariant distributions. This gives another proof of a result of Babillott-Ledrappier.
