Closed trapping horizons without singularity

Abstract

In gravitational collapse leading to black hole formation, trapping horizons typically develop inside the contracting matter. Classically, an ingoing trapping horizon moves towards the centre where it reaches a curvature singularity, while an outgoing horizon moves towards the surface of the star where it becomes an isolated, null horizon. However, strong quantum effects at high curvature close to the centre could modify the classical picture substantially, e.g. by deflecting the ingoing horizon to larger radii, until it eventually reunites with the outgoing horizon. We here analyse some existing models of regular "black holes" of finite lifespan formed out of ingoing null shells collapsing from ${\mathcal{I}}^{-}$, after giving general conditions for the existence of (singularity-free) closed trapping horizons. We study the energy-momentum tensor of such models by solving Einstein's equations in reverse and give an explicit form of the metric to model a Hawking radiation reaching ${\mathcal{I}}^{+}$. A major flaw of the models aiming at describing the formation of black holes (with a Vaidya limit on ${\mathcal{I}}^{-}$) as well as their evaporation is finally exhibited: they necessarily violate the null energy condition up to ${\mathcal{I}}^{-}$, i.e. in a non-compact region of spacetime.

arXiv comment26 pages, 20 figures

References in corpus (27)

• Formation and evaporation of non-singular black holes
• Regular Black Hole in General Relativity Coupled to Nonlinear Electrodynamics
• A Covariant Entropy Conjecture
• General Laws of Black-Hole Dynamics
• Notes on non-singular models of black holes
• Black hole evaporation: A paradigm
• Local existence of dynamical and trapping horizons
• Planck stars
• Information loss problem and a `black hole' model with a closed apparent horizon
• Information Preservation and Weather Forecasting for Black Holes
• A model for non-singular black hole collapse and evaporation
• Marginally trapped tubes and dynamical horizons
• Spherically symmetric spacetimes with a trapped surface
• Spherical black holes with regular center: a review of existing models including a recent realization with Gaussian sources
• Physical observability of horizons
• Quantum radiation from an evaporating non-singular black hole
• The lifetime problem of evaporating black holes: mutiny or resignation
• On the Effective Metric of a Planck Star
• The time evolution of marginally trapped surfaces
• Foliation dependence of black hole apparent horizons in spherical symmetry
• Black hole evaporation without an event horizon
• Causal Nature and Dynamics of Trapping Horizons in Black Hole Collapse
• Global and Local Horizon Quantum Mechanics
• Do Black Holes Exist?
• The disinformation problem for black holes (conference version)
• The semi-classical stress-energy tensor in a Schwarzschild background, the information paradox, and the fate of an evaporating black hole
• Horizon quantum fuzziness for non-singular black holes

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• Regular black holes and the first law of black hole mechanics
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• Trapping Horizons of the Evolving Charged Wormhole and Black Bounce
• Semiclassical black holes and horizon singularities
• Nomen non est omen: Why it is too soon to identify ultra-compact objects as black holes
• Matter and forces near physical black holes
• Physical black holes in fourth-order gravity
• Quantum effects across dynamical horizons
• Null shells: general matching across null boundaries and connection with cut-and-paste formalism
• Kinematic and energy properties of dynamical regular black holes
• General matching across Killing horizons of zero order
• A dialog on the fate of information in black hole evaporation
• Quantum Collapse of a Thin Shell Revisited
• Physical black holes in semiclassical gravity
• Evaporation of a nonsingular Reissner-Nordström black hole and information loss problem
• Research on high-frequency quasi-periodic oscillations in black bounce-type spacetime
• Proper time Quantization of a Thin Shell
• On gravitational spherical collapse without spacetime singularity
• Black holes and their horizons in semiclassical and modified theories of gravity
• Apparent horizon as a membrane
• A quantum thin shell surrounding a Black Hole