Many-Body Delocalization in Strongly Disordered System with Long-Range Interactions: Finite Size Scaling

Abstract

The localization in a disordered system of $N$ interacting spins coupled by the long-range anisotropic interaction $1/R^{\alpha }$ is investigated using a finite size scaling in a $d=1$ -dimensional system for $N=8,10,12,14$. The results supports the absence of localization in the infinite system at $\alpha <2d$ and a scaling of a critical energy disordering $W_c\propto N^{2d-\alpha }$ in agreement with the analytical theory suggesting the energy delocalization in the subset of interacting resonant pairs of spins as a precursor of the many-body delocalization.The spin relaxation rate $k$ dependence on disordering $k\propto W^{-2}$ has been revealed in the practically interesting case $\alpha =d$. This relaxation mechanism can be responsible for the anomalous relaxation of quantum two level systems in amorphous solids.

5 pages, 4 figures

References in corpus (4)

• Localization of interacting fermions at high temperature
• Phenomenology of fully many-body-localized systems
• Interferometric probes of many-body localization
• Entanglement growth in many-body localized systems with long-range interactions