Electron mass shift in nonthermal systems

TL;DR

This paper investigates the electron mass shift in nonthermal systems, showing that while thermal shifts are small, nonequilibrium conditions can significantly enhance the effect through large current fluctuations.

Contribution

It provides a formulation based on Coulomb gauge that predicts smaller mass shifts and explores how nonequilibrium conditions can amplify the effect.

Findings

Thermal electron mass shift is small.

Nonequilibrium conditions can increase the mass shift.

Large current fluctuations can enhance the effect by orders of magnitude.

Abstract

The electron mass is known to be sensitive to local fluctuations in the electromagnetic field, and undergoes a small shift in a thermal field. It was claimed recently that a very large electron mass shift should be expected near the surface of a metal hydride [{\it Eur. Phys. J. C}, {\bf 46} 107 (2006)]. We examine the shift using a formulation based on the Coulomb gauge, which leads to a much smaller shift. The maximization of the electron mass shift under nonequilibrium conditions seems nonetheless to be an interesting problem. We consider a scheme in which a current in a hollow wire produces a large vector potential in the wire center. Fluctuations in an LC circuit with nearly matched loss and gain can produce large current fluctuations; and these can increase the electron mass shift by orders of magnitude over its room temperature value.