Induced circular polarization on photons due to interaction with axion-like particles in rotating magnetic field of neutron stars

We investigate how the photon polarization is affected by the interaction with axion-like particles (ALPs) in the rotating magnetic field of a neutron star (NS). Using quantum Boltzmann equations the study demonstrates that the periodic magnetic field of millisecond NSs enhances the interaction of photons with ALPs and creates a circular polarization on them. A binary system including an NS and a companion star could serve as a probe. When the NS is in front of the companion star with respect to the earth observer, there is a circular polarization on the previously linearly polarized photons as a result of the interaction with ALPs there. After a half-binary period, the companion star passes in front of the NS, and the circular polarization of photons disappears and changes to linear. The excluded parameter space for a millisecond NS with 300 Hz rotating frequency, highlights the coupling constant of 1.7 x 10(-11) GeV-1 <= g(a gamma gamma) <= 1.6 x 10(-3) GeV-1 for the ALP masses in the range of 7 x 10(-12) eV <= m(a) <= 1.5 x 10(3) eV.