Probing many-body quantum chaos with quantum simulators

TL;DR

This paper introduces a protocol using randomized measurements to experimentally probe spectral form factors, revealing quantum chaos, thermalization, and localization in many-body systems.

Contribution

It proposes a novel measurement scheme for spectral form factors and partial spectral form factors in quantum simulators, enabling experimental study of many-body quantum chaos.

Findings

Protocol successfully measures SFF and PSFF in spin models

Reveals signatures of quantum chaos and localization

Numerical simulations validate the approach

Abstract

The spectral form factor (SFF), characterizing statistics of energy eigenvalues, is a key diagnostic of many-body quantum chaos. In addition, partial spectral form factors (PSFFs) can be defined which refer to subsystems of the many-body system. They provide unique insights into energy eigenstate statistics of many-body systems, as we show in an analysis on the basis of random matrix theory and of the eigenstate thermalization hypothesis. We propose a protocol that allows the measurement of the SFF and PSFFs in quantum many-body spin models, within the framework of randomized measurements. Aimed to probe dynamical properties of quantum many-body systems, our scheme employs statistical correlations of local random operations which are applied at different times in a single experiment. Our protocol provides a unified testbed to probe many-body quantum chaotic behavior, thermalization and many-body localization in closed quantum systems which we illustrate with numerical simulations for Hamiltonian and Floquet many-body spin-systems.