Non-equilibrium electromagnetic fluctuations: Heat transfer and interactions

TL;DR

This paper extends the scattering formalism to analyze heat transfer and Casimir forces in non-equilibrium systems with bodies at different temperatures, providing new insights into radiation interactions and validating approximation methods.

Contribution

It introduces a formalism for non-equilibrium electromagnetic fluctuations, enabling analysis of heat transfer and forces between objects at different temperatures.

Findings

Radiation from a cylinder is polarized.

Heat transfer between a sphere and a plate is characterized.

Proximity transfer approximation is valid at close separations.

Abstract

The Casimir force between arbitrary objects in equilibrium is related to scattering from individual bodies. We extend this approach to heat transfer and Casimir forces in non-equilibrium cases where each body, and the environment, is at a different temperature. The formalism tracks the radiation from each body and its scatterings by the other objects. We discuss the radiation from a cylinder, emphasizing its polarized nature, and obtain the heat transfer between a sphere and a plate, demonstrating the validity of proximity transfer approximation at close separations and arbitrary temperatures.