From ergodicity to Stark many-body localization in spin chains with single-ion anisotropy

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Hauptverfasser: Sousa, M. G., Costa, Rafael F. P., Neto, G. D. de Moraes, Vernek, E.
Format: Preprint
Veröffentlicht: 2024
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author Sousa, M. G.
Costa, Rafael F. P.
Neto, G. D. de Moraes
Vernek, E.
author_facet Sousa, M. G.
Costa, Rafael F. P.
Neto, G. D. de Moraes
Vernek, E.
contents The principles of ergodicity and thermalization constitute the foundation of statistical mechanics, positing that a many-body system progressively loses its local information as it evolves. Nevertheless, these principles can be disrupted when thermalization dynamics lead to the conservation of local information, as observed in the phenomenon known as many-body localization. Quantum spin chains provide a fundamental platform for exploring the dynamics of closed interacting quantum many-body systems. This study explores the dynamics of a spin chain with $S\geq 1/2$ within the Majumdar-Ghosh model, incorporating a non-uniform magnetic field and single-ion anisotropy. Through the use of exact numerical diagonalization, we unveil that a nearly constant-gradient magnetic field suppress thermalization, a phenomenon termed Stark many-body localization (SMBL), previously observed in $S=1/2$ chains. Furthermore, our findings reveal that the sole presence of single-ion anisotropy is sufficient to prevent thermalization in the system. Interestingly, when the magnitudes of the magnetic field and anisotropy are comparable, they compete, favoring delocalization. Despite the potential hindrance of SMBL by single-ion anisotropy in this scenario, it introduces an alternative mechanism for localization. Our interpretation, considering local energetic constraints and resonances between degenerate eigenstates, not only provides insights into SMBL but also opens avenues for future experimental investigations into the enriched phenomenology of disordered free localized $S\geq 1/2$ systems.
format Preprint
id arxiv_https___arxiv_org_abs_2401_03111
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle From ergodicity to Stark many-body localization in spin chains with single-ion anisotropy
Sousa, M. G.
Costa, Rafael F. P.
Neto, G. D. de Moraes
Vernek, E.
Quantum Physics
Disordered Systems and Neural Networks
The principles of ergodicity and thermalization constitute the foundation of statistical mechanics, positing that a many-body system progressively loses its local information as it evolves. Nevertheless, these principles can be disrupted when thermalization dynamics lead to the conservation of local information, as observed in the phenomenon known as many-body localization. Quantum spin chains provide a fundamental platform for exploring the dynamics of closed interacting quantum many-body systems. This study explores the dynamics of a spin chain with $S\geq 1/2$ within the Majumdar-Ghosh model, incorporating a non-uniform magnetic field and single-ion anisotropy. Through the use of exact numerical diagonalization, we unveil that a nearly constant-gradient magnetic field suppress thermalization, a phenomenon termed Stark many-body localization (SMBL), previously observed in $S=1/2$ chains. Furthermore, our findings reveal that the sole presence of single-ion anisotropy is sufficient to prevent thermalization in the system. Interestingly, when the magnitudes of the magnetic field and anisotropy are comparable, they compete, favoring delocalization. Despite the potential hindrance of SMBL by single-ion anisotropy in this scenario, it introduces an alternative mechanism for localization. Our interpretation, considering local energetic constraints and resonances between degenerate eigenstates, not only provides insights into SMBL but also opens avenues for future experimental investigations into the enriched phenomenology of disordered free localized $S\geq 1/2$ systems.
title From ergodicity to Stark many-body localization in spin chains with single-ion anisotropy
topic Quantum Physics
Disordered Systems and Neural Networks
url https://arxiv.org/abs/2401.03111