Generic Axion Maxwell Equations: Path Integral Approach

Abstract

AbstractThe low energy interactions between axions and electromagnetic fields that arise in models with heavy dyons charged under a spontaneously broken global axial U(1) symmetry are derived using the path integral approach. Hence, generic axion‐Maxwell equations relevant for experimental searches are obtained. It is found that the structure of the axion Maxwell equations can be significantly different compared to what is normally assumed in the literature, as the derived equations feature new axion‐dependent terms including CP‐violating ones. The new terms can reconcile the Peccei–Quinn solution to the strong CP problem with astrophysical axion hints, as well as give unique signatures in light‐shining‐through‐wall and haloscope experiments. Moreover, via the latter signatures, these experiments can indirectly probe the existence of heavy dyons.