Single-site measurements as probes of many-body quantum chaos

This talk is based on our recent paper [1], where 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. The long-time dynamics of both quantities exhibit the correlation hole (ramp-plateau structure), indicating many-body quantum chaos. These results show that the experimental detection of dynamical fingerprints of many-body quantum chaos are within reach of existing technology.

[1] I. Vallejo-Fabila, A. Kumar Das, S. Choudhury, and L. F. Santos, “Single-site measurements as probes of many-body quantum chaos”, Phys. Rev. E 112, 044208 (2025).