Theory of friction: the contribution from a fluctuating electromagnetic field

Abstract

We calculate the friction force between two semi-infinite solids in relative parallel motion (with velocity V), and separated by a vacuum gap of width d. The friction force results 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.