Thermodynamic decoupling in the deep-strong coupling regime

TL;DR

This paper investigates the deep-strong coupling regime where light-matter interaction leads to effective decoupling, revealing that heat currents also vanish, which has significant implications for quantum thermodynamics and thermal machines.

Contribution

The study introduces a thermodynamically consistent global master equation for the DSC regime and demonstrates that heat currents approach zero, highlighting the role of virtual photons.

Findings

Heat current approaches zero in the DSC regime.

Decoupling extends beyond local observables to nonlocal energy fluxes.

Implications for quantum thermotronics and thermal device design.

Abstract

In the deep-strong coupling (DSC) regime, the interaction between light and matter exceeds their bare frequencies, leading to an effective decoupling. Theoretical and experimental evidence for this behavior has relied solely on measurements of local observables at equilibrium. However, such a local approach is insufficient to accurately describe energy fluxes in critical and nonequilibrium phenomena. Here, we use a two-terminal quantum junction to derive a thermodynamically consistent global master equation. We demonstrate that the associated heat current, a key nonlocal observable in any quantum thermal machine, also approaches zero in this extreme coupling scenario, underscoring the role of virtual photons in the vacuum ground state. Our results indicate that the decoupling is a more general feature of the DSC regime, with implications for quantum thermotronics.