Dephasing-induced diffusive transport in anisotropic Heisenberg model

TL;DR

This paper investigates how dephasing affects transport in an anisotropic Heisenberg model, revealing that dephasing induces diffusive behavior across various parameters and analyzing the resulting spin conductivity and correlations.

Contribution

It demonstrates that dephasing universally induces diffusive transport in the anisotropic Heisenberg model under disordered fields, extending understanding of quantum transport mechanisms.

Findings

Dephasing induces normal diffusive transport in the model.

Spin conductivity depends on dephasing strength.

Long-range order persists for finite chain sizes.

Abstract

We study transport properties of anisotropic Heisenberg model in a disordered magnetic field experiencing dephasing due to external degrees of freedom. In the absence of dephasing the model can display, depending on parameter values, the whole range of possible transport regimes: ideal ballistic conduction, diffusive, or ideal insulating behavior. We show that the presence of dephasing induces normal diffusive transport in a wide range of parameters. We also analyze the dependence of spin conductivity on the dephasing strength. In addition, by analyzing the decay of spin-spin correlation function we discover a presence of long-range order for finite chain sizes. All our results for a one-dimensional spin chain at infinite temperature can be equivalently rephrased for strongly-interacting disordered spinless fermions.