Seminar

Photon propagation in a cold axion background and strong magnetic fields

By
Albert Renau (UB)
Date
Place
Aula 507 (Facultat de Física, UB)
seminar ICCUB
In this work we analyze the propagation of photons in an environment where a strong magnetic field (perpendicular to the photon momenta) coexists with an oscillating cold axion background with the characteristics expected from dark matter in the galactic halo.

Qualitatively, the main effect of the combined background is to produce a three-way mixing among the two photon polarizations and the axion. It is interesting to note that in spite of the extremely weak interaction of photons with the axion background, its effects may compete with those coming from the magnetic field in some regions of the parameter space.

We determine (with one plausible simplification) the proper frequencies and eigenvectors, and the corresponding photon ellipticities that depend both on the magnetic field and the local density of axions. We also comment on the feasibility of interferometric and polarimetric table-top experiments to detect the latter.