Signatures of bath-induced quantum avalanches in a many-body--localized system

TL;DR

This study experimentally investigates quantum avalanches in a many-body-localized system coupled to a thermal bath, revealing how localized systems can delocalize through bath-induced dynamics and thermalization.

Contribution

We experimentally demonstrate bath-induced quantum avalanches in a many-body-localized system and analyze their dynamics and impact on localization.

Findings

Evidence of accelerated transport indicating quantum avalanches

Site-resolved entropy measurements show avalanche propagation

Multipoint correlations reveal bath-system interaction dynamics

Abstract

Strongly correlated systems can exhibit surprising phenomena when brought in a state far from equilibrium. A spectacular example are quantum avalanches, that have been predicted to run through a many-body--localized system and delocalize it. Quantum avalanches occur when the system is locally coupled to a small thermal inclusion that acts as a bath. Here we realize an interface between a many-body--localized system and a thermal inclusion of variable size, and study its dynamics. We find evidence for accelerated transport into the localized region, signature of a quantum avalanche. By measuring the site-resolved entropy we monitor how the avalanche travels through the localized system and thermalizes it site by site. Furthermore, we isolate the bath-induced dynamics by evaluating multipoint correlations between the bath and the system. Our results have fundamental implications on the robustness of many-body--localized systems and their critical behavior.