Negative differential thermal conductance and heat amplification in a nonequilibrium triangle-coupled spin-boson system at strong coupling

TL;DR

This paper analyzes nonequilibrium quantum heat transfer in a triangle-coupled spin-boson system, revealing negative differential conductance and heat amplification at strong coupling, with implications for thermal management.

Contribution

It provides an analytical study of heat transfer and amplification in a nonequilibrium spin-boson system using advanced approximation methods at strong coupling.

Findings

Negative differential thermal conductance observed at strong coupling

Giant heat amplification factor identified in the system

Strong qubit-bath interaction is essential for these effects

Abstract

We investigate the nonequilibrium quantum heat transfer in a triangle-coupled spin-boson system within a three-terminal setup. By including the nonequilibrium noninteracting blip approximation approach combined with the full counting statistics, we analytically obtain the steady state populations and heat currents. The negative differential thermal conductance and giant heat amplification factor are clearly observed at strong qubit-bath coupling. %and the heat amplification is dramatically suppressed in the moderate coupling regime. Moreover, the strong interaction between the gating qubit and gating thermal bath is unraveled to be compulsory to exhibit these far-from equilibrium features.