Optical properties of dynamical axion backgrounds

by Luís Ventura (U. Aveiro)

Friday 10 Jan 2020, 11:00 → 12:00 Europe/Stockholm

Nordita East

In this work, we study the optical properties of axion-like particle (ALP) and ALP-plasma backgrounds induced by the Chern-Simons interaction term.  We determine spectral distortions, time-delays and light deflection, following  “No chiral light bending by clumps of axion-like particles” (arXiv:1910.06128).We find, with regards to light deflection: i) there is no birefringent light deflection at first order in the ALP-photon coupling, O(g), in a pure ALP background, confirming the results of arXiv:1910.06128, ii) there is, however, birefringent light deflection at O(g) in a ALP-plasma background.
We find, with regards to spectral distortions: i) there is a frequency/momentum shift at O(g) depending solely on the endpoints of the photon trajectory, in a pure ALP background, confirming the results of arXiv:1910.06128, ii) there is, however, a cumulative frequency shift at O(g) (in the presence of a plasma) or O(g^2) (pure background).
We speculate about the effect of the plasma on the various observables and discuss several open issues.