A remark on unique ergodicity and the contact type condition

Abstract

We prove that for a broad class of exact symplectic manifolds including \({\mathbb{R}^{2m}}\), the Hamiltonian flow on a regular compact energy level of an autonomous Hamiltonian cannot be uniquely ergodic. This is a consequence of the Weinstein conjecture and the observation that a Hamiltonian structure with non-vanishing self-linking number must have contact type. We apply these results to show that certain types of exact twisted geodesic flows cannot be uniquely ergodic.