Fundamental limits for non-contact transfers between two bodies

TL;DR

This paper establishes fundamental theoretical limits on energy and momentum transfer between two bodies separated by a gap, using a variational approach and transmission eigenmode analysis.

Contribution

It introduces a general variational framework to derive upper bounds on non-contact energy and momentum transfer between arbitrary media.

Findings

Derived upper limits for energy and momentum flux.

Provided optimal reflectivity coefficients for different media.

Unified approach using fluctuational electrodynamics and quantum field theory.

Abstract

We investigate energy and momentum non-contact exchanges between two arbitrary flat media separated by a gap. This problem is revisited as a transmission problem of individual system eigenmodes weighted by a transmission probability obtained either from fluctuational electrodynamics or quantum field theory. An upper limit for energy and momentum flux is derived using a general variational approach. The corresponding optimal reflectivity coefficients are given both for identical and different media in interaction.