Exact Diagonalization Study on Avalanches in Many-Body Localized Constrained Spin Chains

Fuente: arXiv
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Autor principal: Lu, Shuangyuan
Formato: Preprint
Publicado: 2024
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author Lu, Shuangyuan
author_facet Lu, Shuangyuan
contents Avalanches are believed to be the mechanism behind the transition from many-body localization to the thermal phase. We utilize spin chains with constraints to study the physics of quantum avalanches by exact diagonalization of disordered systems coupled to a thermal bath. Single-spin observables are used to characterize localization and quantify the influence of the thermal bath on disordered spin chains. Constraints on the Hilbert space confine the dynamics to a subspace, effectively reducing the Hilbert space dimension and enabling the study of larger systems with limited computational resources. We study the PXP model, and in addition, we construct spin chains with constraints by searching for constraints with a genetic algorithm to reach larger system sizes. We define quantities to measure the strength of avalanches and use these to compare different models. We find that avalanches are more pronounced in models with constraints compared to those without constraints. Results from exact diagonalization are compared with those from studying the Lindblad master equation. We also identify models that exhibit no thermal phases and find stable ergodicity breaking.
format Preprint
id arxiv_https___arxiv_org_abs_2408_14372
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Exact Diagonalization Study on Avalanches in Many-Body Localized Constrained Spin Chains
Lu, Shuangyuan
Disordered Systems and Neural Networks
Statistical Mechanics
Strongly Correlated Electrons
Avalanches are believed to be the mechanism behind the transition from many-body localization to the thermal phase. We utilize spin chains with constraints to study the physics of quantum avalanches by exact diagonalization of disordered systems coupled to a thermal bath. Single-spin observables are used to characterize localization and quantify the influence of the thermal bath on disordered spin chains. Constraints on the Hilbert space confine the dynamics to a subspace, effectively reducing the Hilbert space dimension and enabling the study of larger systems with limited computational resources. We study the PXP model, and in addition, we construct spin chains with constraints by searching for constraints with a genetic algorithm to reach larger system sizes. We define quantities to measure the strength of avalanches and use these to compare different models. We find that avalanches are more pronounced in models with constraints compared to those without constraints. Results from exact diagonalization are compared with those from studying the Lindblad master equation. We also identify models that exhibit no thermal phases and find stable ergodicity breaking.
title Exact Diagonalization Study on Avalanches in Many-Body Localized Constrained Spin Chains
topic Disordered Systems and Neural Networks
Statistical Mechanics
Strongly Correlated Electrons
url https://arxiv.org/abs/2408.14372