Spectral gap and quantitative statistical stability for systems with contracting fibers and Lorenz-like maps
Stefano Galatolo, Rafael Lucena
TL;DR
The paper develops a spectral-gap framework for transfer operators of systems preserving a contracting foliation, using anisotropic spaces built from leafwise disintegrations. By proving Lasota-Yorke inequalities and a Perron-Frobenius–type decomposition, it obtains exponential convergence to equilibrium and a spectral gap for the transfer operator on both L^1-like and L^∞-like strong spaces. The framework is then applied to Lorenz-like two-dimensional maps to derive quantitative statistical stability under deterministic perturbations, with an asymptotically optimal modulus of continuity O(δ log δ) in BV-like norms. A uniform BV Lorenz-like family is studied to provide robust stability results and explicit rates, supported by extensive Appendix technicalities on disintegration and operator uniformity. This work advances quantitative understanding of statistical stability for piecewise smooth, fiber-contracting dynamics, with practical implications for Lorenz-like systems and related skew-product models.
Abstract
We consider transformations preserving a contracting foliation, such that the associated quotient map satisfies a Lasota-Yorke inequality. We prove that the associated transfer operator, acting on suitable normed spaces, has a spectral gap (on which we have quantitative estimation). As an application we consider Lorenz-like two dimensional maps (piecewise hyperbolic with unbounded contraction and expansion rate): we prove that those systems have a spectral gap and we show a quantitative estimate for their statistical stability. Under deterministic perturbations of the system of size $δ$, the physical measure varies continuously, with a modulus of continuity $O(δ\log δ)$, which is asymptotically optimal for this kind of piecewise smooth maps.
