Dephasing-assisted transport in a tight-binding chain with a linear potential

TL;DR

This paper investigates how dephasing noise can enhance quantum transport in a linear potential system, revealing optimal conditions for maximum current and providing analytical expressions validated by experiments.

Contribution

It provides an analytical expression for steady-state current considering both dephasing and tilt, advancing understanding of environment-assisted quantum transport.

Findings

Maximum current occurs when dephasing rate matches Bloch oscillation period.

Current exhibits a maximum as a function of system size with fixed total tilt.

Analytical results closely match exact solutions across parameter ranges.

Abstract

An environment interacting with a quantum system can enhance transport through the suppression of quantum effects responsible for localization. In this paper, we study the interplay between bulk dephasing and a linear potential in a boundary-driven tight-binding chain. A linear potential induces Wannier-Stark localization in the absence of noise, while dephasing induces diffusive transport in the absence of a tilt. We derive an approximate expression for the steady-state current as a function of both dephasing and tilt which closely matches the exact solution for a wide range of parameters. From it, we find that the maximum current occurs for a dephasing rate equal to the period of Bloch oscillations in the Wannier-Stark localized system. We also find that the current displays a maximum as a function of the system size, provided that the total potential tilt across the chain remains constant. Our results can be verified in current experimental platforms and represents a step forward in analytical studies of environment-assisted transport.