2015/11/30 by David J. Luitz, Nicolas Laflorencie, Fabien Alet · 1 citation
Physics and Astronomy · #cond-mat.dis-nn
paper · pdf · doi:10.1103/physrevb.93.060201
published as Phys. Rev. B 93, 060201 (2016) · 5 pages, 3 figures
arxiv created 2017/05/29 · arxiv updated 2017/05/30
Many-body localization is characterized by a slow logarithmic growth of the entanglement entropy after a global quantum quench while the local memory of an initial density imbalance remains at infinite time. We investigate how much the proximity of a many-body localized phase can influence the dynamics in the delocalized ergodic regime where thermalization is expected. Using an exact Krylov space technique, the out-of-equilibrium dynamics of the random-field Heisenberg chain is studied up to L=28 sites, starting from an initially unentangled high-energy product state. Within most of the delocalized phase, we find a sub-ballistic entanglement growth S(t)∝ t1/z with a disorder-dependent exponent z≥1, in contrast with the pure ballistic growth z=1 of clean systems. At the same time, anomalous relaxation is also observed for the spin imbalance \calI(t)∝ t-ζ with a continuously varying disorder-dependent exponent ζ, vanishing at the transition. This provides a clear experimental signature for detecting this non-conventional regime.