Quantum Theory of Triboelectricity

We propose a microphysical theory of the triboelectric effect by which mechanical rubbing separates charges across the interface between two materials. Surface electrons are treated as an open system coupled to two baths, corresponding to the bulks. Extending Zel’dovich’s theory of bosonic superradiance, we show that motion-induced population inversion can generate an electromotive force. We argue that this is consistent with the basic phenomenology of triboelectrification and triboluminescence as irreversible processes, and we suggest how to carry out more precise experimental tests.

Figure 1

The triboelectric generator sketched maintains a current $I$ along the circuit if an external motor spins the cylinder of material $A$ and radius $R$ at a sufficient angular velocity $\mathrm{\Omega }$ with respect to another material $B$.

Figure 2

Sketch of the currents $j_a$ of Eq. (20) and $j_b$ of Eq. (24), for the open system $a$, $b$ in a steady state.