Rotation of the polarization plane in axion fields: application to neutron star polar cap regions

Abstract

We study observable manifestations of an axion field, focusing on possible polarizational effects for electromagnetic wave propagating in such a special magnetoelectric medium. The corresponding analysis is based on a geometric model of the Casimir type, in the framework of which the rotation angle of the polarization plane is derived to the lowest order. The results obtained are discussed for astrophysical conditions of a neutron star, where an existence of a locally inhomogeneous axion region is predicted in the polar cap.

Comments: 19 pages, 1 figure