Continuous Axion Photon Duality and its Consequences

TL;DR

This paper explores the continuous duality symmetry in the axion-photon system under magnetic fields, deriving conservation laws, relating it to scalar QED, and discussing implications for axion-photon condensation and wave amplitudes.

Contribution

It reveals a continuous duality symmetry in the axion-photon system, connects it to scalar QED, and discusses potential for axion-photon condensation in high magnetic fields.

Findings

Derived conservation law from duality symmetry.

Mapped axion-photon interaction to scalar QED.

Established constraints on wave amplitudes.

Abstract

The axion photon system in an external magnetic field, when for example considered with the geometry of the experiments exploring axion photon mixing, displays a continuous axion-photon duality symmetry in the limit the axion mass is neglected. The conservation law that follows from this symmetry is obtained. The magnetic field interaction is seen to be equivalent to first order to the interaction of a complex charged field with an external electric potential, where this ficticious "electric potential" is proportional to the external magnetic field. This allows to solve for the scattering amplitudes using already known scalar QED results. It is argued that in more generic conditions (not just related to these experiments) axion-photon condensation could be obtained for high magnetic fields. Finally an exact constraint originating fromthe current conservation on the amplitudes of reflected and transmited waves is obtained.