Phenomenology of ultralight bosons around compact objects: in-medium suppression

TL;DR

This paper investigates how plasma environments around black holes affect the mixing and conversion of ultralight bosons with photons, impacting potential observational signatures and superradiance phenomena.

Contribution

It provides a detailed analysis of in-medium suppression effects on axion-photon and dark photon-photon mixing near black holes, highlighting plasma density's role.

Findings

Plasma density can significantly suppress boson-photon conversion.

Conversion rates are affected by black hole charge and plasma conditions.

Implications for detecting ultralight bosons via astrophysical observations.

Abstract

Mixing between ultralight bosons and the Standard Model photon may allow access to the hitherto invisible Universe. In the presence of plasma, photons are dressed with an effective mass which will influence the conversion between the two. We study this phenomenon, known as in-medium suppression, in the context of black hole physics. We consider both axion-photon mixing around charged black holes and dark photon-photon mixing around neutral black holes. We find that the presence of plasma indeed influences the conversion rate, possibly quenching it altogether for large plasma densities, and discuss implications for superradiance and observational signatures.