Single-site measurements as probes of many-body quantum chaos
Phys. Rev. E 112, 044208 – Published 7 October, 2025
DOI: https://doi.org/10.1103/9tt6-fkf6
Abstract
We demonstrate that the dynamics of an observable localized at a single-site is sufficient to determine whether a many-body quantum system exhibits level statistics characteristic of random matrix theory, which is a widely used diagnostic of quantum chaos. Specifically, we analyze the spin autocorrelation function at a single site evolving under a disordered spin-1/2 chain, a setup realizable in ongoing experimental platforms. We also investigate the partial (subsystem) survival probability, recently measured in cold-atom experiments, thereby broadening discussions on detecting many-body quantum chaos via survival probability [Phys. Rev. Res. 7, 013181 (2025)]. Given the precision and timescales currently achievable, our results indicate that the detection of many-body quantum chaos through dynamical observables is feasible but constrained to small system sizes.
