Speaker
Description
Ultralight bosons are a prominent type of axion-like dark matter. These particles may form clouds around black holes through the superradiance process. The remaining system with a boson cloud around a black hole is often called a gravitational atom due to the similarities to the electron cloud of a hydrogen atom. In this talk I will discuss one of the first non-perturbative explorations of gravitational atoms with numerical relativity. To this end, we numerically investigate free and self-interacting ultralight scalar fields around black holes in General Relativity. We focus on complex scalar fields Φ whose self-interactions are described by the quartic potential V ∝ λ|Φ|4, and ignore the black hole spin in order to disentangle the effects of self-interactions on the boson cloud. I will present our findings for self-interacting bosonic clouds around black holes and discuss technical challenges. Our results provide useful inputs for fully dynamical numerical relativity simulations and I will end the talk with an outlook for future explorations of spinning black holes and real scalar fields.
