Quantum hair of black holes out of equilibrium

Understand

Classically, the black hole (BH) horizon is completely opaque, hiding any clues about the state and very existence of its interior.

• Quantum mechanically and in equilibrium, the situation is not much different: Hawking radiation will now be emitted, but it comes out at an extremely slow rate, is thermal to a high degree of accuracy and thus carries a minimal amount of information about the quantum state within the BH.
• Here, it is shown that the situation is significantly different when a quantum BH is out of equilibrium.
• We argue that the BH can then emit "supersized" Hawking radiation with a much larger amplitude than that emitted in equilibrium.