Radiation backreaction in axion electrodynamics

TL;DR

This paper analyzes energy conservation in axion-electrodynamics, identifies energy transfer mechanisms, and quantifies axion damping in magnetic fields, with implications for axion cosmology.

Contribution

It provides a Hamiltonian formulation of energy transfer in axion-electrodynamics and quantifies axion damping times in magnetic backgrounds.

Findings

Energy transfer term identified in the Hamiltonian framework.

Axion-to-light Primakoff process analyzed in static magnetic fields.

Axion damping time comparable to the Universe's age in certain mass ranges.

Abstract

Energy-momentum conservation of classical axion-electrodynamics is carefully analyzed in the Hamiltonian formulation of the theory. The term responsible for the energy transfer between the electromagnetic and the axion sectors is identified. As a special application the axion-to-light Primakoff-process in the background of a static magnetic field is worked out and the radiative self-damping of the axion oscillations is characterized quantitatively. The damping time turns out comparable to the age of the Universe in the preferred axion mass range.