Markov Extensions and Conditionally Invariant Measures for Certain Logistic Maps with Small Holes

TL;DR

This paper investigates quadratic maps with small holes, establishing the existence of conditionally invariant measures with bounded densities, and demonstrating exponential escape rates and convergence to SRB measures.

Contribution

It introduces a Markov extension method to prove the existence of conditionally invariant measures for quadratic maps with holes, a novel approach in this context.

Findings

Existence of absolutely continuous conditionally invariant measure with bounded density.

Exponential escape rate of Lebesgue measure from the system.

Convergence of the measure to the SRB measure as the hole size decreases.

Abstract

We study the family of quadratic maps f_a(x) = 1 - ax^2 on the interval [-1,1] with a between 0 and 2. When small holes are introduced into the system, we prove the existence of an absolutely continuous conditionally invariant measure using the method of Markov extensions. The measure has a density which is bounded away from zero and is analogous to the density for the corresponding closed system. These results establish the exponential escape rate of Lebesgue measure from the system, despite the contraction in a neighborhood of the critical point of the map. We also prove convergence of the conditionally invariant measure to the SRB measure for f_a as the size of the hole goes to zero.