The bad and rough rotation is Poissonian

Abstract

Motivated by the Berry-Tabor Conjecture and the seminal work of Rudnick-Sarnak, the fine-scale properties of sequences $(a_n\alpha {)}_{n\in \mathbb{N}}\mathrm{mod}1$ with $(a_n{)}_{n\in \mathbb{N}}\subseteq \mathbb{N}$ and $\alpha$ irrational have been extensively studied in the last decades. In this article, we prove that for $(a_n{)}_{n\in \mathbb{N}}$ arising from the set of rough numbers with explicit roughness parameters and any badly approximable $\alpha$, $(a_n\alpha {)}_{n\in \mathbb{N}}\mathrm{mod}1$ has Poissonian correlations of all orders, and consequently, Poissonian gaps. This is the first known explicit sequence $(a_n\alpha {)}_{n\in \mathbb{N}}\mathrm{mod}1$ with these properties. Further, we show that this result is false for Lebesgue almost every $\alpha$, thereby disproving a conjecture of Larcher and Stockinger [Math. Proc. Camb. Phil. Soc. 2020]. The method of proof makes use of an equidistribution result mod $d$ in diophantine Bohr sets which might be of independent interest.

arXiv comment35 pages; added some references and an appendix concerning numerical experiments