Quantum bound states around black holes

Quantum mechanics in the vicinity of black holes is a fascinating field of theoretical physics. It involves both general relativity and particle physics, opening new eras to establish the principles of unified theories. In this article, we show that quantum bound states with no classical equivalent – as can easily be seen at the dominant monopolar order – should be formed around black holes for massive scalar particles. We qualitatively investigate some important physical consequences, in particular for the Hawking evaporation mechanism and the associated greybody factors.