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Bera, Soumya ; De Tomasi, Giuseppe ; Weiner, Felix ; Evers, Ferdinand

Density Propagator for Many-Body Localization: Finite-Size Effects, Transient Subdiffusion, and Exponential Decay

Bera, Soumya, De Tomasi, Giuseppe, Weiner, Felix und Evers, Ferdinand (2017) Density Propagator for Many-Body Localization: Finite-Size Effects, Transient Subdiffusion, and Exponential Decay. Physical Review Letters 118 (19), S. 196801.

Veröffentlichungsdatum dieses Volltextes: 25 Jun 2021 04:44
Artikel
DOI zum Zitieren dieses Dokuments: 10.5283/epub.46115


Zusammenfassung

We investigate charge relaxation in quantum wires of spinless disordered fermions (t−V model). Our observable is the time-dependent density propagator Πϵ(x,t), calculated in windows of different energy density ϵ of the many-body Hamiltonian and at different disorder strengths W, not exceeding the critical value Wc. The width Δxϵ(t) of Πϵ(x,t) exhibits a behavior dlnΔxϵ(t)/dlnt=βϵ(t), where the ...

We investigate charge relaxation in quantum wires of spinless disordered fermions (t−V model). Our observable is the time-dependent density propagator Πϵ(x,t), calculated in windows of different energy density ϵ of the many-body Hamiltonian and at different disorder strengths W, not exceeding the critical value Wc. The width Δxϵ(t) of Πϵ(x,t) exhibits a behavior dlnΔxϵ(t)/dlnt=βϵ(t), where the exponent function βϵ(t)≲1/2 is seen to depend strongly on L at all investigated parameter combinations. (i) We confirm the existence of a region in phase space that exhibits subdiffusive dynamics in the sense that βϵ(t)<1/2 in a large window of times. However, subdiffusion might possibly be transient, only, finally giving way to a conventional diffusive behavior with βϵ=1/2. (ii) We cannot confirm the existence of many-body mobility edges even in regions of the phase diagram that have been reported to be deep in the delocalized phase. (iii) (Transient) subdiffusion 0<βϵ(t)≲1/2 coexists with an enhanced probability for returning to the origin Πϵ(0,t), decaying much slower than 1/Δxϵ(t). Correspondingly, the spatial decay of Πϵ(x,t) is far from Gaussian, being exponential or even slower. On a phenomenological level, our findings are broadly consistent with the effects of strong disorder and (fractal) Griffiths regions.



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Details

DokumentenartArtikel
Titel eines Journals oder einer ZeitschriftPhysical Review Letters
Verlag:American Physical Society (APS)
Band:118
Nummer des Zeitschriftenheftes oder des Kapitels:19
Seitenbereich:S. 196801
Datum12 Mai 2017
InstitutionenPhysik > Institut für Theoretische Physik > Lehrstuhl Ferdinand Evers
Identifikationsnummer
WertTyp
10.1103/PhysRevLett.118.196801DOI
Dewey-Dezimal-Klassifikation500 Naturwissenschaften und Mathematik > 530 Physik
StatusVeröffentlicht
BegutachtetJa, diese Version wurde begutachtet
An der Universität Regensburg entstandenZum Teil
URN der UB Regensburgurn:nbn:de:bvb:355-epub-461159
Dokumenten-ID46115

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