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arXiv · 1604.08567

Diffusive and subdiffusive spin transport in the ergodic phase of a many-body localizable system

Marko Znidaric·Antonello Scardicchio·Vipin Kerala Varma
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Abstract

We study high temperature spin transport in a disordered Heisenberg chain in the ergodic regime. By employing a density matrix renormalization group technique for the study of the stationary states of the boundary-driven Lindblad equation we are able to study extremely large systems (400 spins). We find both a diffusive and a subdiffusive phase depending on the strength of the disorder and on the anisotropy parameter of the Heisenberg chain. Studying finite-size effects we show numerically and theoretically that a very large crossover length exists that controls the passage of a clean-system dominated dynamics to one observed in the thermodynamic limit. Such a large length scale, being larger than the sizes studied before, explains previous conflicting results. We also predict spatial profiles of magnetization in steady states of generic nondiffusive systems.

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Marko Znidaric, Antonello Scardicchio, Vipin Kerala Varma. 2016-07-25. Diffusive and subdiffusive spin transport in the ergodic phase of a many-body localizable system. https://doi.org/10.1103/physrevlett.117.040601

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