On the distribution of Sudler products and Birkhoff sums for the irrational rotation

Fuente: arXiv
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Main Author: Borda, Bence
Format: Preprint
Published: 2021
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author Borda, Bence
author_facet Borda, Bence
contents We study the value distribution of the Sudler product $\prod_{n=1}^N |2 \sin (πn α)|$ and the Diophantine product $\prod_{n=1}^N (2e\| n α\|)$ for various irrational $α$, as $N$ ranges in a long interval of integers. At badly approximable irrationals these products exhibit strong concentration around $N^{1/2}$, and at certain quadratic irrationals they even satisfy a central limit theorem. In contrast, at almost every $α$ we observe an interesting anticoncentration phenomenon when the typical and the extreme values are of the same order of magnitude. Our methods are equally suited for the value distribution of Birkhoff sums $\sum_{n=1}^N f(n α)$ for circle rotations. Using Diophantine approximation and Fourier analysis, we find the first and second moment for an arbitrary periodic $f$ of bounded variation, and (almost) prove a conjecture of Bromberg and Ulcigrai on the appropriate scaling factor in a so-called temporal limit theorem. Birkhoff sums also satisfy a central limit theorem at certain quadratic irrationals.
format Preprint
id arxiv_https___arxiv_org_abs_2104_06716
institution arXiv
publishDate 2021
record_format arxiv
spellingShingle On the distribution of Sudler products and Birkhoff sums for the irrational rotation
Borda, Bence
Dynamical Systems
11K60, 37A50, 37E10
We study the value distribution of the Sudler product $\prod_{n=1}^N |2 \sin (πn α)|$ and the Diophantine product $\prod_{n=1}^N (2e\| n α\|)$ for various irrational $α$, as $N$ ranges in a long interval of integers. At badly approximable irrationals these products exhibit strong concentration around $N^{1/2}$, and at certain quadratic irrationals they even satisfy a central limit theorem. In contrast, at almost every $α$ we observe an interesting anticoncentration phenomenon when the typical and the extreme values are of the same order of magnitude. Our methods are equally suited for the value distribution of Birkhoff sums $\sum_{n=1}^N f(n α)$ for circle rotations. Using Diophantine approximation and Fourier analysis, we find the first and second moment for an arbitrary periodic $f$ of bounded variation, and (almost) prove a conjecture of Bromberg and Ulcigrai on the appropriate scaling factor in a so-called temporal limit theorem. Birkhoff sums also satisfy a central limit theorem at certain quadratic irrationals.
title On the distribution of Sudler products and Birkhoff sums for the irrational rotation
topic Dynamical Systems
11K60, 37A50, 37E10
url https://arxiv.org/abs/2104.06716