Quantum thermal rectification via state-dependent two-photon dissipation

TL;DR

This paper explores quantum thermal rectification using a harmonic oscillator coupled to thermal baths via linear and nonlinear processes, revealing how state-dependent two-photon dissipation enables directional heat flow at different temperatures.

Contribution

It introduces a novel mechanism for quantum thermal rectification based on state-dependent two-photon dissipation and proposes an implementation scheme involving an auxiliary two-level system.

Findings

Rectification arises from low-temperature suppression of two-photon emission.

Higher temperatures involve asymmetric scaling of higher-order moments.

Nonlinear dissipation conditions enable directional heat flow.

Abstract

Controlling heat flow at the quantum level is essential for the development of next-generation thermal devices. We investigate thermal rectification in a quantum harmonic oscillator coupled to two thermal baths via both single-photon (linear) and two-photon (nonlinear) exchange processes. At low temperatures, rectification arises from a state-dependent suppression of two-photon emission: when the cold bath dominates, it drives the oscillator into low-occupancy states, inhibiting emission and creating a thermal bottleneck. At higher temperatures, rectification is governed by the asymmetric scaling of higher-order moments associated with two-photon absorption and emission. We systematically explore various bath coupling configurations and identify the conditions under which nonlinear dissipation leads to directional heat flow. Furthermore, we propose an implementation scheme based on coupling an auxiliary two-level system to the oscillator, enabling effective two-photon dissipation. These results contribute to the understanding of quantum heat transport in the presence of nonlinear dissipation and may support future efforts in nanoscale thermal rectification design.