Semiclassical black holes and horizon singularities

Abstract

In spherical symmetry, solutions of the semiclassical Einstein equations belong to one of two possible classes. Both classes contain solutions that -- depending on the dynamic behavior of the horizon -- describe evaporating physical black holes or expanding white holes (trapped/anti-trapped regions that form in finite time of a distant observer). These solutions are real-valued only if the null energy condition (NEC) is violated in the vicinity of the Schwarzschild sphere. We review their properties and describe the only consistent black hole formation scenario. While the curvature scalars are finite on the outer apparent/anti-trapping horizon, it is still a weakly singular surface. This singularity manifests itself in a mild firewall. Near the inner apparent horizon, the NEC is satisfied. Models of static regular black holes are known to be unstable, but since dynamic models of regular black holes are severely constrained by self-consistency requirements, their stability requires further investigation.

12 pages, 3 figures. Published version. Invited contribution to the special topic collection "Celebrating Sir Roger Penrose's Nobel Prize" published in AVS Quantum Science. Comments welcome!

References in corpus (12)

• Notes on non-singular models of black holes
• Spacetime Structure of an Evaporating Black Hole in Quantum Gravity
• The 1965 Penrose singularity theorem
• Warp drive basics
• Observation of Incipient Black Holes and the Information Loss Problem
• Minimal conditions for the existence of a Hawking-like flux
• Physical observability of horizons
• Versatile method for renormalized stress-energy computation in black-hole spacetimes
• Foliation dependence of black hole apparent horizons in spherical symmetry
• Quasi-particle creation by analogue black holes
• Renormalized stress-energy tensor for stationary black holes
• Singularities, black holes, and cosmic censorship: A tribute to Roger Penrose

Cited by in corpus (10)

• Regular black holes and the first law of black hole mechanics
• Nomen non est omen: Why it is too soon to identify ultra-compact objects as black holes
• Matter and forces near physical black holes
• Kinematic and energy properties of dynamical regular black holes
• Models of cosmological black holes
• Physical black holes in semiclassical gravity
• Kodama-like Vector Fields in Axisymmetric Spacetimes
• Horizon-bound objects: Kerr--Vaidya solutions
• Black holes and their horizons in semiclassical and modified theories of gravity
• Constraining modified gravity theories with physical black holes