Multifractality and its role in anomalous transport in the disordered XXZ spin-chain

Autor: David J. Luitz, Ivan M. Khaymovich, Yevgeny Bar Lev
Jazyk: angličtina
Rok vydání: 2020
Předmět:
Zdroj: SciPost Physics Core, Vol 2, Iss 2, p 006 (2020)
Druh dokumentu: article
ISSN: 2666-9366
DOI: 10.21468/SciPostPhysCore.2.2.006
Popis: The disordered XXZ model is a prototype model of the many-body localization transition (MBL). Despite numerous studies of this model, the available numerical evidence of multifractality of its eigenstates is not very conclusive due severe finite size effects. Moreover it is not clear if similarly to the case of single-particle physics, multifractal properties of the many-body eigenstates are related to anomalous transport, which is observed in this model. In this work, using a state-of-the-art, massively parallel, numerically exact method, we study systems of up to 24 spins and show that a large fraction of the delocalized phase flows towards ergodicity in the thermodynamic limit, while a region immediately preceding the MBL transition appears to be multifractal in this limit. We discuss the implication of our finding on the mechanism of subdiffusive transport.
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