Hitting statistics for $φ$-mixing dynamical systems
Saeed Shaabanian
TL;DR
This work derives a unifying L_{α,s}(Λ) limit for hitting-time statistics and localized escape rates in φ-mixing and Gibbs-Markov dynamical systems, with Λ a nested intersection of shrinking sets of measure tending to zero. The main result expresses L_{α,s}(Λ) as 1 in the absence of short returns (π_{ess}(U_n)→∞) or as the extremal-index-based value θ_1 when short returns persist, for α in a broad range (including α=0) and under explicit decay and regularity assumptions. The authors extend these recurrence results to Gibbs-Markov systems, metric-ball observables, and provide concrete examples: a singleton, a Cantor set, and a submanifold of an Anosov map (cat map), illustrating how the extremal index and short-return structure control recurrence. Overall, the paper broadens hitting-time and escape-rate theory to zero-measure targets in polynomially φ-mixing and Gibbs-Markov settings, with implications for hyperbolic dynamics and Young tower frameworks.
Abstract
Hitting rate and escape rate are two examples of recurrence laws for a dynamical system, and a general limit connects them. We show that for both Gibbs-Markov systems or any systems with the $φ$-mixing measure, for a sequence of nested sets whose intersection is a measure zero set, this general limit equals one in the absence of short returns and less than one otherwise, which is given by an explicit formula called extremal index. One of the applications of this result is to dynamical systems on Riemannian manifolds such as hyperbolic maps and expanding maps, and it can be applied to any system with a suitable Young tower.
