Many-body delocalization from embedded thermal inclusion

TL;DR

This paper investigates how rare thermal regions within disordered quantum spin chains cause slow thermalization, revealing universal spectral behavior and exponential decay of spin imbalance, advancing understanding of many-body localization.

Contribution

It introduces a numerical study of quantum avalanches triggered by embedded thermal inclusions, demonstrating their impact on slow dynamics in many-body localized systems.

Findings

Evidence of exponentially slow thermalization due to rare regions

Persistent decay of spin imbalance over long timescales

Universal spectral function behavior observed

Abstract

We numerically study quantum avalanches in one-dimensional disordered spin systems by attaching two XXZ spin chains. One chain has low disorder representing a rare Griffith's region, or thermal inclusion, and the second has larger disorder, i.e., disorder larger than the observed finite-size crossover. Comparing dynamics of this system to identical systems with uniformly large disorder, we find evidence for exponentially slow thermalization (in disorder) within the many-body localized regime when the rare region is present. We observe a decay of the spin imbalance in the bulk of the large disorder region that persists to long times ($\sim10^{4}$) and find a universal behavior of the spectral function.