Simplest description of charge propagation in a strong background

Abstract

Exploiting the gauge freedom associated with the Volkov description of a charge propagating in a plane wave background, we identify a new type of gauge choice which significantly simplifies the theory. This allows us to develop a compact description of the propagator for both scalar and fermionic matter, in a circularly polarized background. It is shown that many of the usually observed structures are gauge artifacts. We then analyze the full ultraviolet behavior of the one-loop corrections for such charges. This enables us to identify and contrast the different renormalization prescriptions needed for both types of matter.