Imperfect many-body localization in exchange-disordered isotropic spin chains

We investigate many-body localization in isotropic Heisenberg spin chains with the local exchange parameters being subject to quenched disorder. Such systems incorporate a nonabelian symmetry in their Hamiltonian by invariance under global SU(2)-rotations. Nonabelian symmetries are predicted to hind...

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Bibliographic Details
Published inNew journal of physics Vol. 25; no. 12; pp. 123002 - 123011
Main Authors Siegl, Julian, Schliemann, John
Format Journal Article
LanguageEnglish
Published Bristol IOP Publishing 01.12.2023
Subjects
Heisenberg chain
Investigations
Localization
Many body problem
many-body localization
Numerical analysis
Phase transitions
Physics
Probability distribution
Random variables
Sample variance
Symmetry
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Summary:We investigate many-body localization in isotropic Heisenberg spin chains with the local exchange parameters being subject to quenched disorder. Such systems incorporate a nonabelian symmetry in their Hamiltonian by invariance under global SU(2)-rotations. Nonabelian symmetries are predicted to hinder the emergence of a many-body localized phase even in the presence of strong disorder. We report on numerical studies using exact diagonalization for chains of common spin length 1 / 2 and 1. The averaged consecutive-gap ratios display a transition compatible with a crossover from an ergodic phase at small disorder strength to an incompletely localized phase at stronger disorder. Studying the sample-to-sample variance of the averaged consecutive-gap ratio, we distinguish this incompletely localized phase from the fully many-body localized phase by its scaling behavior.
Bibliography:NJP-116538.R1
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ISSN:1367-2630
1367-2630
DOI:10.1088/1367-2630/ad0e1b