Theory of friction: contribution from fluctuating electromagnetic field

TL;DR

This paper develops a theoretical model for the friction force between two solids in relative motion, mediated by fluctuating electromagnetic fields, and explores its dependence on temperature, velocity, and separation distance.

Contribution

It provides a detailed theoretical calculation of electromagnetic fluctuation-induced friction between solids, including temperature effects and limiting cases.

Findings

Friction force arises from electromagnetic fluctuations and is related to van der Waals interactions.

The model predicts how friction varies with velocity, separation, and temperature.

Limiting cases for small and large velocities and distances are analyzed.

Abstract

We calculate the friction force between two semi-infinite solids in relative parallel motion (velocity $V$), and separated by a vacuum gap of width $d$. The friction force result from coupling via a fluctuating electromagnetic field, and can be considered as the dissipative part of the van der Waals interaction. We consider the dependence of the friction force on the temperature $T$, and present a detailed discussion of the limiting cases of small and large $V$ and $d$.