Constraints on pseudoscalar-photon interaction from CMB polarization observation

TL;DR

This paper reviews how CMB polarization measurements can constrain pseudoscalar-photon interactions, which could indicate new physics like Lorentz invariance violation, by analyzing polarization rotation effects over cosmological distances.

Contribution

It provides a comprehensive review of current constraints on pseudoscalar-photon interactions derived from CMB polarization data, highlighting their significance for fundamental physics.

Findings

CMB polarization observations set limits on pseudoscalar-photon coupling strength.

Potential violation of Lorentz invariance or CPT symmetry is constrained by polarization rotation.

The review emphasizes the role of future observations in probing new physics.

Abstract

Effective pseudoscalar-photon interaction(s) would induce a rotation of linear polarization of electromagnetic wave propagating with cosmological distance in various cosmological models. Pseudoscalar-photon interaction is proportional to the gradient of the pseudoscalar field. From phenomenological point of view, this gradient could be neutrino number asymmetry, other density current, or a constant vector. In these situations, Lorentz invariance or CPT may effectively be violated. CMB polarization observations are superb tests of these models and have the potential to discover new fundamental physics. In this paper, we review the constraints on pseudoscalar-photon interaction from CMB polarization observation.