Quantum fluctuation theorem for heat exchange in the strong coupling regime

TL;DR

This paper derives a quantum fluctuation theorem for heat exchange in a strongly coupled multi-state impurity system, providing a closed-form cumulant generating function and analyzing heat currents.

Contribution

It introduces a fluctuation theorem applicable in the strong coupling regime and derives a closed-form expression for the cumulant generating function.

Findings

Steady-state fluctuation theorem holds under strong coupling.

Derived a closed-form cumulant generating function.

Analyzed heat current and cumulants in a nonlinear thermal junction.

Abstract

We study quantum heat exchange in a multi-state impurity coupled to two thermal reservoirs. Allowing for strong system-bath interactions, we show that a steady-state heat exchange fluctuation theorem holds, though the dynamical processes nonlinearly involve the two reservoirs. We accomplish a closed expression for the cumulant generating function, and use it obtain the heat current and its cumulants in a nonlinear thermal junction, the two-bath spin-boson model.