Quantum theory of triboelectricity*

We propose a microphysical theory of the triboelectric effect by which mechanical rubbing separates charges across the interface between two surfaces. Surface electrons are treated as an open system, weakly coupled to two baths, corresponding to the bulk materials. We show that an electromotive force can be irreversibly generated from the motion-induced population inversion of fermions, thus extending and generalizing Zel'dovich's theory of bosonic superradiance. We argue that this is consistent with the basic phenomenology of triboelectrification and triboluminescence as off-equilibrium processes. We also propose a direct experimental test of our predictions that may clarify the longstanding question of the relation between triboelectrification and dry friction.

This work has been published in PRL 125, 186101 (2020)