Axion Electrodynamics in Strong Magnetic Backgrounds

TL;DR

This paper explores the extreme magnetic field regime in axion electrodynamics, revealing phenomena like birefringence, photon canalization, and QED coupling suppression, with implications for astrophysical processes such as pulsar radiation.

Contribution

It introduces the overcritical magnetic field regime in axion-electrodynamics and analyzes its effects on photon behavior and QED interactions, a novel exploration beyond standard models.

Findings

Strong birefringence and screening effects predicted.

Extraordinary photons can be canalized along curved magnetic fields.

QED coupling can be significantly suppressed at high magnetic fields.

Abstract

The overcritical regime of axion-electrodynamics (AED) is investigated. For magnetic fields larger than the characteristic scale linked to AED, quantum vacuum fluctuations due to axion-like fields can dominate over those associated with the electron-positron fields. This hypothetical regime of the dominance of AED over QED is predicted to induce strong birefringence and screening effects. We show that, if the magnetic field lines are curved, extraordinary photons could be canalized along the field direction. It is also shown that the running QED coupling depends on the magnetic field strength, and for certain energy regimes, it could be screened almost to zero, making the QED building blocks very weakly interacting between each other. The impact of this phenomenon on the radiation mechanism of pulsars is discussed.