Many-Body Floquet Theory for Radiative Heat Transfer in Time-Modulated Systems

TL;DR

This paper introduces a comprehensive Floquet theory for radiative heat transfer in systems with time-modulated optical properties, enabling active control and amplification of thermal radiation at the nanoscale.

Contribution

It extends fluctuational electrodynamics to nonstationary systems, deriving closed-form heat current expressions and a Landauer-like formulation that includes inelastic frequency conversion.

Findings

Time modulation redistributes thermal fluctuations across Floquet sidebands.

Modulation acts as a parametric amplifier of thermal radiation.

The theory enables frequency-selective control of nanoscale heat transfer.

Abstract

We develop a general theory of radiative heat exchange between dipoles with time-modulated optical properties. This framework extends fluctuational electrodynamics beyond equilibrium by incorporating nonstationary correlations and memory effects induced by temporal modulation. Closed-form expressions for the heat currents in modulated many-body systems are obtained, together with a generalized Landauer-like formulation of the pairwise exchanges, where the transmission coefficient accounts for all inelastic frequency-conversion channels. Near-resonant modulation redistributes and amplifies thermal fluctuations across Floquet sidebands, acting as a parametric amplifier of thermal radiation and enabling active, frequency-selective control of nanoscale heat transfer.