Metric entropy and homoclinic growth rate

Abstract

In this paper, we investigate the relationship between chaos and homoclinic orbits from a quantitative perspective. Let f be a C^r diffeomorphism (r > 1) on a compact Riemannian manifold preserving an ergodic hyperbolic measure. We show that the homoclinic growth rate is bounded below by the metric entropy. This result generalizes the work of Mendoza from surfaces to higher-dimensional systems from a measure-theoretic viewpoint. We also examine the sharpness of this estimate by demonstrating that, in the Newhouse domain, C^r-generic diffeomorphisms exhibit a superexponential growth in the number of homoclinic points.