The hidden negative differential thermal conductance

TL;DR

This paper reveals the emergence of negative differential thermal conductance in a quantum system using Bloch-Redfield dynamics, highlighting the importance of beyond-Lindblad approaches for accurate modeling of nonlinear quantum thermal transport.

Contribution

It demonstrates that beyond-Lindblad dynamics can predict NDTC in quantum thermal systems, contrasting with Lindblad predictions.

Findings

NDTC observed using Bloch-Redfield equations

Lindblad dynamics fails to predict NDTC

Highlights importance of accurate quantum thermodynamic modeling

Abstract

Negative differential thermal conductance (NDTC), a hallmark of nonlinear quantum thermal transport, plays a critical role in the design of quantum thermal devices such as thermal diodes and transistors. The Lindblad dynamics predicts that the heat current through two coupled atoms increases with the increasing temperature difference of two bosonic reservoirs. However, in this paper, we uncover the suppressive effect on the heat current in this nonequilibrium system using the Bloch-Redfield master equations, which indicate the emergence of NDTC. Our findings underscore the crucial role of beyond-Lindblad dynamics in accurately capturing nonlinear features in quantum thermodynamic systems.