Rectification of heat currents across nonlinear quantum chains: A versatile approach beyond weak thermal contact

TL;DR

This paper introduces a comprehensive method for analyzing heat transfer and rectification in nonlinear quantum chains, effective across various coupling strengths, nonlinearities, and external conditions, advancing nanoscale quantum thermodynamics.

Contribution

It presents a versatile approach applicable to mesoscopic quantum devices with continuous degrees of freedom, capable of handling strong couplings, nonlinearities, disorder, and time-dependent fields.

Findings

Effective heat rectification in anharmonic oscillator chains.

Method works from weak to strong system-reservoir couplings.

Applicable to long chains and higher-dimensional systems.

Abstract

Within the emerging field of quantum thermodynamics the issues of heat transfer and heat rectification are basic ingredients for the understanding and design of heat engines or refrigerators at nanoscales. Here, a consistent and versatile approach for mesoscopic devices operating with continuous degrees of freedom is developed valid from low up to strong system-reservoir couplings and over the whole temperature range. It allows to cover weak to moderate nonlinearities and is applicable to various scenarios including the presence of disorder and external time-dependent fields. As a particular application coherent one-dimensional chains of anharmonic oscillators terminated by thermal reservoirs are analyzed with particular focus on rectification. The efficiency of the method opens a door to treat also rather long chains and extensions to higher dimensions and geometries.