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arXiv · 2211.04816

Imperfect Many-Body Localization in Exchange-Disordered Isotropic Spin Chains

Julian Siegl·John Schliemann
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Abstract

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 an invariance under global SU(2)-rotations. Nonabelian symmetries are predicted to hinder the emergence of a many-body localized phase even in 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. The sample-to-sample variance of the averaged consecutive-gap ratio displays a maximum at the transition and distinguishes the incompletely localized phase from a fully many-body localized phase by its scaling behavior.

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Julian Siegl, John Schliemann. 2022-11-09. Imperfect Many-Body Localization in Exchange-Disordered Isotropic Spin Chains. https://doi.org/10.1088/1367-2630/ad0e1b

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