Venue: Maths 103
Black holes are key players in a wide range of fundamental physics with a rich phenomenology. Here, I will focus on the superradiant effect of Kerr BHs which can yield to instabilities when surrounded by a ``mirror''. This setup arises naturally in asymptotically anti-de Sitter spacetimes or in the presence of massive fields surrounding the BH, which can model condensates of ultra-light bosonic fields such as axion-like particles or dark matter candidates. Thus, exploring the superradiant instability of Kerr BHs opens up the exciting possibility to better understand fundamental fields by observing astrophysical BHs. In this talk, I will present recent results concerning massive fields in BH backgrounds as well as first numerical simulations of the fully
non-linear case. We have explored massive scalar fields surrounding Kerr BHs and we have found interesting signatures in the scalar and gravitational wave channel. The BH's response hints at superradiant effects at the non-linear level.