Matter and forces near physical black holes

Abstract

We describe general features of formation and disappearance of regular spherically symmetric black holes in semiclassical gravity. The allowed models are critically dependent on the requirement that the resulting objects evolve in finite time according to a distant observer. Violation of the null energy condition (NEC) is mandatory for this to happen, and we study the properties of the necessary energy-momentum tensor in the vicinity of the apparent horizon. In studies of the kinematics of massive test particles, it is found that the escape from a black hole is possible only on the ingoing trajectories when the particles are overtaken by the contracting outer apparent horizon. Tidal forces experienced by geodesic observers, infalling or escaping, are shown to be finite at the apparent horizon, although this is not true for nongeodesic trajectories.

11 pages, 3 figures. Comments welcome!

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• Warp drive basics
• 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
• Renormalized stress-energy tensor for stationary black holes
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Cited by in corpus (5)

• Black holes as spherically-symmetric horizon-bound objects
• Paradoxes before the paradox: surface gravity and the information loss problem
• Kinematic and energy properties of dynamical regular black holes
• Horizon-bound objects: Kerr--Vaidya solutions
• Apparent horizon as a membrane