Typical orbits of quadratic polynomials with a neutral fixed point: non-Brjuno type

TL;DR

This paper explores the dynamics of quadratic polynomials with neutral fixed points, focusing on measure-theoretic attractors and linearization domains, using near-parabolic renormalization techniques for irrational rotation numbers.

Contribution

It introduces new quantitative and analytic methods to study the fine-scale structure of attractors and bounds on linearization domains for these maps.

Findings

Established an optimal upper bound on the size of the linearization domain.

Analyzed the measure-theoretic properties of attractors.

Connected the size of domains to the Siegel-Brjuno-Yoccoz series.

Abstract

We investigate the quantitative and analytic aspects of the near-parabolic renormalization scheme introduced by Inou and Shishikura in 2006. These provide techniques to study the dynamics of some holomorphic maps of the form $f(z) = e^{2\pi i \alpha} z + \mathcal{O}(z^2)$, including the quadratic polynomials $e^{2\pi i \alpha} z+z^2$, for some irrational values of $\alpha$. The main results of the paper concern fine-scale features of the measure-theoretic attractors of these maps, and their dependence on the data. As a bi-product, we establish an optimal upper bound on the size of the maximal linearization domain in terms of the Siegel-Brjuno-Yoccoz series of $\alpha$.