Quantum Larmor radiation from a moving charge in an electromagnetic plane wave background

TL;DR

This paper investigates the quantum effects on Larmor radiation emitted by a moving charge in a monochromatic electromagnetic plane wave background, revealing a suppression of radiation energy due to quantum inelastic collision effects.

Contribution

It extends previous work by deriving the first-order quantum correction to Larmor radiation in a plane wave background using scalar QED and the in-in formalism.

Findings

Quantum effects suppress total radiation energy compared to classical predictions.

Radiation involves inelastic collisions between electrons and background photons.

First-order quantum correction derived for relativistic and stationary initial states.

Abstract

We extend our previous work [Phys. Rev. D83 045030 (2011)], which investigated the first-order quantum effect in the Larmor radiation from a moving charge in a spatially homogeneous time-dependent electric field. Specifically, we investigate the quantum Larmor radiation from a moving charge in a monochromatic electromagnetic plane wave background based on the scalar quantum electrodynamics at the lowest order of the perturbation theory. Using the in-in formalism, we derive the theoretical formula of the total radiation energy from a charged particle in the initial states being at rest and being in a relativistic motion. Expanding the theoretical formula in terms of the Planck constant \hbar, we obtain the first-order quantum effect on the Larmor radiation. The quantum effect generally suppresses the total radiation energy compared with the prediction of the classical Larmor formula, which is a contrast to the previous work. The reason is explained by the fact that the radiation from a moving charge in a monochromatic electromagnetic plane wave is expressed in terms of the inelastic collisions between an electron and photons of the background electromagnetic waves.