Open-system spin transport and operator weight dissipation in spin chains

TL;DR

This paper investigates how dissipation-assisted operator evolution influences transport behavior in various one-dimensional spin chains, revealing that the preservation or breaking of conserved quantities determines the transport scaling.

Contribution

It demonstrates how DAOE affects transport in spin chains depending on whether it preserves or breaks system symmetries, across different integrable and chaotic models.

Findings

DAOE preserves transport scaling when symmetries are maintained.

Breaking conserved quantities leads to diffusive transport behavior.

Transport properties are controlled by the impact of DAOE on conserved quantities.

Abstract

We use non-equilibrium steady states to study the effect of dissipation-assisted operator evolution (DAOE) on the scaling behavior of transport in one-dimensional spin chains. We consider three models in the XXZ family: the XXZ model with staggered anisotropy, which is chaotic; XXZ model with no external field and tunable interaction, which is Bethe ansatz integrable and (in the zero interaction limit) free fermion integrable; and the disordered XY model, which is free-fermion integrable and Anderson localized. We find evidence that DAOE's effect on transport is controlled by its effect on the system's conserved quantities. To the extent that DAOE preserves those symmetries, it preserves the scaling of the system's transport properties; to the extent it breaks those conserved quantities, it pushes the system towards diffusive scaling of transport.