Localized Axion Photon States in a Strong Magnetic Field

TL;DR

This paper introduces localized axion-photon soliton solutions in a strong magnetic field, revealing stable configurations with distinct magnetic flux and non-trivial U(1) charge, advancing understanding of axion-electromagnetic interactions.

Contribution

It presents the first derivation of localized soliton solutions in axion-photon systems considering back reaction effects in a strong magnetic field.

Findings

Identified stable localized soliton solutions with unique magnetic flux.

Demonstrated the existence of non-trivial U(1) charge in these solutions.

Showed these solutions differ from the vacuum state with only a constant magnetic field.

Abstract

We consider the axion field and electromagnetic waves with rapid time dependence, coupled to a strong time independent, asymptotically approaching a constant at infinity "mean" magnetic field, which takes into account the back reaction from the axion field and electromagnetic waves with rapid time dependence in a time averaged way. The direction of the self consistent mean field is orthogonal to the common direction of propagation of the axion and electromagnetic waves with rapid time dependence and parallel to the polarization of these electromagnetic waves. Then, there is an effective U(1) symmetry mixing axions and photons. Using the natural complex variables that this U(1) symmetry suggests we find localized planar soliton solutions. These solutions appear to be stable since they produce a different magnetic flux than the state with only a constant magnetic field, which we take as our "ground state". The solitons also have non trivial U(1) charge defined before, different from the uncharged vacuum.