Quantum recurrences and the arithmetic of Floquet dynamics

TL;DR

This paper develops an algebraic framework to identify and analyze exact quantum recurrences in finite-dimensional Floquet systems, revealing conditions under which such recurrences occur or are ruled out.

Contribution

It introduces a novel arithmetic approach using algebraic field theory to precisely determine recurrence times in quantum Floquet systems, extending beyond approximate methods.

Findings

Enumerates all candidate recurrence times using cyclotomic spectrum analysis.

Rigorously rules out exact recurrences for certain Hamiltonian parameters.

Shows rational parameters do not generally guarantee exact recurrence.

Abstract

The Poincar\'e recurrence theorem shows that conservative systems in a bounded region of phase space eventually return arbitrarily close to their initial state after a finite amount of time. An analogous behavior occurs in certain quantum systems where quantum states can recur after sufficiently long unitary evolution, a phenomenon known as quantum recurrence. Periodically driven (i.e. Floquet) quantum systems in particular exhibit complex dynamics even in small dimensions, motivating the study of how interactions and Hamiltonian structure affect recurrence behavior. While most existing studies treat recurrence in an approximate, distance-based sense, here we address the problem of exact, state-independent recurrences in a broad class of finite-dimensional Floquet systems, spanning both integrable and non-integrable models. Leveraging techniques from algebraic field theory, we construct an arithmetic framework that identifies all possible recurrence times by analyzing the cyclotomic structure of the Floquet unitary's spectrum. This computationally efficient approach yields both positive results, enumerating all candidate recurrence times and definitive negative results, rigorously ruling out exact recurrences for given Hamiltonian parameters. We further prove that rational Hamiltonian parameters do not, in general, guarantee exact recurrence, revealing a subtle interplay between system parameters and long-time dynamics. Our findings sharpen the theoretical understanding of quantum recurrences, clarify their relationship to quantum chaos, and highlight parameter regimes of special interest for quantum metrology and control.