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Evers, Ferdinand ; Bera, Soumya

The internal clock of many-body (de-)localization

Evers, Ferdinand and Bera, Soumya (2023) The internal clock of many-body (de-)localization. Phys. Rev. B (Editor's Suggestion) 108, p. 134204. (Submitted)

Date of publication of this fulltext: 23 Feb 2023 15:43
Article
DOI to cite this document: 10.5283/epub.53858


Abstract

After a decade of many claims to the opposite, there now is a growing consensus that generic disordered quantum wires, e.g., the XXZ-Heisenberg chain, do not exhibit many-body localization (MBL)-at least not in a strict sense within a reasonable window of disorder values W. Specifically, computational studies of short wires exhibit an extremely slow but unmistakable flow of physical observables ...

After a decade of many claims to the opposite, there now is a growing consensus that generic disordered quantum wires, e.g., the XXZ-Heisenberg chain, do not exhibit many-body localization (MBL)-at least not in a strict sense within a reasonable window of disorder values W. Specifically, computational studies of short wires exhibit an extremely slow but unmistakable flow of physical observables with increasing time and system size ("creep") that is consistently directed away from (strict) localization. Our work sheds fresh light on delocalization physics: Strong sample-to-sample fluctuations indicate the absence of a generic time scale, i.e., of a naive "clock rate"; however, the concept of an "internal clock" survives, at least in an ensemble sense. Specifically, we investigate the relaxation of the imbalance I(t) and its temporal fluctuations F(t) and the entanglement and Renyi entropies, Se(t) and S2(t), in a one-dimensional system of interacting disordered fermions. We observe that adopting Se(t), S2(t) as a measure for the internal time per sample reduces the sample-to-sample fluctuations but does not eliminate them. However, a (nearly) perfect collapse of the average I(t) and F(t) for different W is obtained when plotted against Se(t) or S2(t), indicating that the average entropy appropriately models the ensemble-averaged internal clock. We take the tendency for faster-than-logarithmic growth of Se(t) together with the smooth dependency on W of all our observables within the entire simulation window as support for the crossover scenario, discouraging an MBL transition within the traditional parametric-window of computational studies.



Involved Institutions


Details

Item typeArticle
Journal or Publication TitlePhys. Rev. B (Editor's Suggestion)
Publisher:AMER PHYSICAL SOC
Place of Publication:COLLEGE PK
Volume:108
Page Range:p. 134204
Date23 February 2023
InstitutionsPhysics > Institute of Theroretical Physics > Chair Ferdinand Evers
Identification Number
ValueType
2302.11384arXiv ID
10.1103/PhysRevB.108.134204DOI
UNSPECIFIEDURN
Related URLs
URLURL Type
https://arxiv.org/abs/2302.11384Preprint
KeywordsENTANGLEMENT; LOCALIZATION; ENTROPY
Dewey Decimal Classification500 Science > 530 Physics
StatusSubmitted
RefereedNo, this version has not been refereed yet (as with preprints)
Created at the University of RegensburgPartially
URN of the UB Regensburgurn:nbn:de:bvb:355-epub-538588
Item ID53858

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