Effective oscillatory magnetic charges and electric dipole moments induced by axion-photon coupling

Abstract

We suppose that the covariance of Lagrangians always taking place results in a distortion of any electric and magnetic field by a pseudoscalar field of dark matter axions and axion-like particles. As a result, electric and magnetic fields acquire oscillating magnetic and electric components, respectively. The Maxwell-like equations are rigorously derived. One can also use an equivalent approach based on an introduction of effective oscillating magnetic charges and electric dipole moments in undistorted electromagnetic fields. The determined relations between the magnetic charges and electric dipole moments and the axion-photon coupling constant open a possibility to compare a sensitivity of search for axions in optical experiments and experiments with massive particles. The dual (inverse) Witten effect defining effective magnetic charges of electrically charged particles opens new exciting possibilities to search for axions and axion-like particles with very small masses in nonresonance experiments. The study of a passage of strongly decelerated electrons or positrons through a solenoid is proposed.