Bera, Soumya and De Tomasi, Giuseppe and Weiner, Felix and Evers, Ferdinand (2017) Density Propagator for Many-Body Localization: Finite-Size Effects, Transient Subdiffusion, and Exponential Decay. PHYSICAL REVIEW LETTERS, 118 (19): 196801. ISSN 0031-9007, 1079-7114
Full text not available from this repository.Abstract
We investigate charge relaxation in quantum wires of spinless disordered fermions (t-V model). Our observable is the time-dependent density propagator Pi(epsilon)(x.t), calculated in windows of different energy density epsilon of the many-body Hamiltonian and at different disorder strengths W, not exceeding the critical value W-c. The width Delta x(epsilon) (t) of Pi(epsilon)(x,t) exhibits a behavior d ln Delta x(epsilon) (t) / d ln t = beta(epsilon)(t) where the exponent function beta(epsilon)(t) less than or similar to 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 beta(epsilon)(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 beta(epsilon) = 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 < beta(epsilon)(t) less than or similar to 1/2 coexists with an enhanced probability for returning to the origin. Pi(epsilon),(0,t) decaying much slower than 1/Delta x(epsilon) (t) Correspondingly, the spatial decay of Pi(epsilon)(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.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | SYSTEM; |
| Subjects: | 500 Science > 530 Physics |
| Divisions: | Physics > Institute of Theroretical Physics > Chair Professor Grifoni > Group Ferdinand Evers |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 14 Dec 2018 13:10 |
| Last Modified: | 28 Feb 2019 08:05 |
| URI: | https://pred.uni-regensburg.de/id/eprint/888 |
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