Evaporating black-to-white hole

This article proposes a generalization of the Oppenheimer-Snyder model which describes a bouncing compact object. The corrections responsible for the bounce are parameterized in a general way so as to remain agnostic about the specific mechanism of singularity resolution at play. It thus develops an effective theory based on a thin shell approach, inferring generic properties of such a UV complete gravitational collapse. The main result comes in the form of a strong constraint applicable to general UV models : if the dynamics of the collapsing star exhibits a bounce, it always occurs below, or at most at the energy threshold of horizon formation, so that only an instantaneous trapping horizon may be formed while a trapped region never forms. This conclusion relies solely on i) the assumption of continuity of the induced metric across the time-like surface of the star and ii) the assumption of a classical Schwarzschild geometry describing the (vacuum) exterior of the star. In particular, it is completely independent of the choice of corrections inside the star which leads to singularityresolution. The present model provides thus a general framework to discuss bouncing compact objects, for which the interior geometry is modeled either by a classical or a quantum bounce. In the latter case, our no-go result regarding the formation of trapped region suggests that additional structure, such as the formation of an inner horizon, is needed to build consistent models of matter collapse describing black-to-white hole bounces. Indeed, such additional structure is needed to keep quantum gravity effects confined to the high curvature regime, in the deep interior region, providing thus a new challenge for current constructions of quantum black-to-white hole bounce models. 4 In this model, the authors use the light-like version of the junction conditions discussed in Ref. [82]. 5 See Ref.[91] for a similar model.

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“…The consequences of this alternative picture has been recently discussed in Refs. [41][42][43]. See also Refs.…”

Section: Introductionmentioning

confidence: 99%

Bouncing compact objects. Part I. Quantum extension of the Oppenheimer-Snyder collapse

Achour

Brahma

Uzan

2020

J. Cosmol. Astropart. Phys.

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“…be a future-directed null vector both normal to and tangential to Σ, let the mass functions m ± (r) be defined according to (13), and define the mass jump [m(r)] by [m(r)] = m + (r) − m − (r).…”

Section: Shell Contributionmentioning

confidence: 99%

“…Many aspects of the "true" spacetime for an evaporating BH remain unknown. There are many proposals for the BH end state [10][11][12], and questions have been raised about in what regimes evaporation dominates the dynamics [13], and about the general applicability of classical spacetimes in describing quantum effects. Nonetheless, BH evaporation appears to be a phenomenon which probably can occur, and for now seems likely to dominate if the environment is sufficiently cold.…”

Section: Introductionmentioning

confidence: 99%

“…Statements like these are ambiguous when there is ambiguity in the stress tensor renormalization scheme. For the present qualitative purposes, suppose the field equations aren't satisfied unless some reasonable renormalization scheme is shown to produce a stress tensor equivalent to the metric 13. This is separate from, but often confused with, the question of radiation experienced by an accelerating particle detector.…”

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confidence: 99%

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Understanding black hole evaporation using explicitly computed Penrose diagrams

Schindler¹,

Aguirre²,

Kuttner³

2020

Phys. Rev. D

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Rigorously computed Penrose diagrams are plotted for a semiclassical model of black hole formation and evaporation, in which black holes form by the accretion of infalling spherical shells of matter and subsequently evaporate by emitting spherical shells of Hawking radiation. The method allows arbitrary interior solutions of the form ds 2 = −f (r) dt 2 +f (r) −1 dr 2 +r 2 dΩ 2 , including singular and nonsingular models. Matter dynamics are visualized by explicitly plotting proper densities and pressures in the diagrams, as well as by tracking the location of trapped surfaces and energy condition violations. The most illustrative model accurately approximates the standard time evolution for black hole thermal evaporation; its time dependence and causal structure are analyzed by inspection of the rigorous diagram. The resulting insights contradict some common intuitions and assumptions, and we point out some examples in the literature with assumptions that do not hold up in our more detailed model. Based on the new diagrams, we argue for an improved understanding of the Hawking radiation process, propose an improved definition of "black hole" in the presence of evaporation, and suggest some implications regarding information preservation and unitarity.

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“…This allows us to consider the quantum mechanical tunneling from the black hole to the white hole, which was discussed in Refs. [32][33][34][35][36][37][38][39][40] and references therein.…”

Section: A and K As Canonically Conjugate Variables And Black-hole-whmentioning

confidence: 99%

Varying Newton Constant and Black Hole to White Hole Quantum Tunneling

Volovik

2020

Universe

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The thermodynamics of black holes is discussed for the case, when the Newton constant G is not a constant, but it is the thermodynamic variable. This gives for the first law of the Schwarzschild black hole thermodynamics: dSBH=−AdK+dMTBH, where the gravitational coupling K=1/4G, M is the black hole mass, A is the area of horizon, and TBH is Hawking temperature. From this first law, it follows that the dimensionless quantity M2/K is the adiabatic invariant, which, in principle, can be quantized if to follow the Bekenstein conjecture. From the Euclidean action for the black hole it follows that K and A serve as dynamically conjugate variables. Using the Painleve–Gullstrand metric, which in condensed matter is known as acoustic metric, we calculate the quantum tunneling from the black hole to the white hole. The obtained tunneling exponent suggests that the temperature and entropy of the white hole are negative.

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Evaporating black-to-white hole

Abstract: We construct and discuss the form of the (effective) spacetime geometry inside a black hole undergoing a quantum transition to a white hole, taking into account the back-reaction of the component of the Hawking radiation falling into the hole.

Cited by 47 publications

References 39 publications

Bouncing compact objects. Part I. Quantum extension of the Oppenheimer-Snyder collapse

Bouncing compact objects. Part I. Quantum extension of the Oppenheimer-Snyder collapse

Understanding black hole evaporation using explicitly computed Penrose diagrams

Varying Newton Constant and Black Hole to White Hole Quantum Tunneling

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