Phonon heat transport in cavity-mediated optomechanical nanoresonators

TL;DR

This paper explores a novel phonon heat transfer mechanism in cavity-mediated optomechanical nanoresonators, revealing oscillatory heat flux and testing thermodynamic uncertainty relations in a far-from-equilibrium quantum system.

Contribution

It introduces a new long-range phonon heat transfer mechanism in cavity-coupled nanoresonators and demonstrates spontaneous heat flux oscillations in nonequilibrium steady states.

Findings

Heat flux oscillates back and forth in steady states.

Universal thermodynamic bound on heat flux verified.

New phenomenon observed in mechanical oscillator heat transfer.

Abstract

The understanding of heat transport in nonequilibrium thermodynamics is an important research frontier, which is crucial for implementing novel thermodynamic devices, such as heat engines and refrigerators. The convection, conduction, and radiation are the well-known basic ways to transfer thermal energy. Here we demonstrate a new mechanism of phonon heat transport between two spatially separated nanomechanical resonators coupled by the cavity-enhanced long-range interactions. The single trajectory for thermalization and non-equilibrium dynamics is monitored in real-time. We find that, in the strong coupling regime, instant heat flux counterintuitively oscillates back and forth in nonequilibrium steady states, which occurs spontaneously above the critical point during the thermal energy transfer process. The universal bound on the precision of nonequilibrium steady-state heat flux, i.e. the thermodynamic uncertainty relation, is verified in such a temperature gradient driven far-off equilibrium system. Our results reveal a previously unobserved phenomenon for heat transfer with mechanical oscillators, and provide a playground for testing fundamental theories in non-equilibrium thermodynamics.