Evading no-hair theorems: hairy black holes in a Minkowski box

Understand

We find hairy black holes of Einstein-Maxwell theory with a complex scalar field that is confined inside a box in a Minkowski background.

• These regular hairy black holes are asymptotically flat and thus the presence of the box or mirror allows to evade well-known no-hair theorems.
• We also find the Israel surface stress tensor that the confining box must have to obey the energy conditions.
• In the zero horizon radius limit, these hairy black holes reduce to a regular asymptotically flat hairy soliton.