Sideband Mixing in Intense Laser Backgrounds

TL;DR

This paper investigates how residual gauge freedom affects the sideband structure of the electron propagator in intense laser backgrounds, showing that gauge transformations do not change pole locations but cause mixing of sidebands.

Contribution

It reveals the impact of residual gauge transformations on the sideband decomposition of the electron propagator in laser backgrounds, clarifying their invariance and mixing behavior.

Findings

Gauge transformations do not alter pole locations.

Sideband structures mix under residual gauge transformations.

Identification of the propagator remains consistent.

Abstract

The electron propagator in a laser background has been shown to be made up of a series of sideband poles. In this paper we study this decomposition by analysing the impact of the residual gauge freedom in the Volkov solution on the sidebands. We show that the gauge transformations do not alter the location of the poles. The identification of the propagator from the two-point function is maintained but we show that the sideband structures mix under residual gauge transformations.