Dephasing enhanced transport in boundary-driven quasiperiodic chains

TL;DR

This paper investigates how dephasing influences transport properties in boundary-driven quasiperiodic chains, revealing that strong dephasing induces diffusion and that optimal noise levels can enhance transport efficiency.

Contribution

It demonstrates that dephasing can turn localized or anomalous transport in quasiperiodic systems into diffusive transport, highlighting a method to control noise-enhanced transport.

Findings

Strong dephasing induces diffusive transport in quasiperiodic chains.

Maximum diffusion coefficient occurs at finite dephasing levels.

Quasiperiodic geometries combined with dephasing can optimize transport control.

Abstract

We study dephasing-enhanced transport in boundary-driven quasi-periodic systems. Specifically we consider dephasing modelled by current preserving Lindblad dissipators acting on the non-interacting Aubry-Andr\'e-Harper (AAH) and Fibonacci bulk systems. The former is known to undergo a critical localization transition with a suppression of ballistic transport above a critical value of the potential. At the critical point, the presence of non-ergodic extended states yields anomalous sub-diffusion. The Fibonacci model, on the other hand, yields anomalous transport with a continuously varying exponent depending on the potential strength. By computing the covariance matrix in the non-equilibrium steady-state, we show that sufficiently strong dephasing always renders the transport diffusive. The interplay between dephasing and quasi-periodicity gives rise to a maximum of the diffusion coefficient for finite dephasing, which suggests the combination of quasi-periodic geometries and dephasing can be used to control noise-enhanced transport.