Scattering approach to near-field radiative heat transfer

TL;DR

This paper develops a quantum scattering theory framework for near-field radiative heat transfer, connecting fluctuational electrodynamics with the Landauer-Büttiker approach, and highlights the role of non-dissipative contributions.

Contribution

It introduces a scattering matrix formulation for matter excitations in near-field heat transfer, unifying diverse physical systems and revealing non-dissipative effects.

Findings

Scattering matrix for matter excitations constructed

Energy current expressed in terms of scattering matrix

Non-dissipative contributions can dominate noise

Abstract

We formulate the problem of near-field radiative heat transfer as an effective quantum scattering theory for excitations of the matter. Built from the same ingredients as the semiclassical fluctuational electrodynamics, the standard tool to handle this problem, our construction makes manifest its relation to the Landauer-B\"uttiker scattering framework, which appears only implicitly in the fluctuational electrodynamics. We show how to construct the scattering matrix for the matter excitations and give a general expression for the energy current in terms of this scattering matrix. We show that the energy current has an important non-dissipative contribution that can dominate the finite-frequency noise while being absent in the average current. Our construction provides a unified description of near-field radiative heat transfer in diverse physical systems.