Vacuum Semiclassical Gravity Does Not Leave Space for Safe Singularities

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Arrechea, Julio and Barceló, Carlos and Boyanov Savov, Valentin and Garay Elizondo, Luis Javier (2021) Vacuum Semiclassical Gravity Does Not Leave Space for Safe Singularities. Universe, 7 (8). p. 281. ISSN 2218-1997

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Official URL: https://doi.org/10.3390/universe7080281



Abstract

General relativity predicts its own demise at singularities but also appears to conveniently shield itself from the catastrophic consequences of such singularities, making them safe. For instance, if strong cosmic censorship were ultimately satisfied, spacetime singularities, although present, would not pose any practical problems to predictability. Here, we argue that under semiclassical effects, the situation should be rather different: the potential singularities which could appear in the theory will generically affect predictability, and so one will be forced to analyse whether there is a way to regularise them. For these possible regularisations, the presence and behaviour of matter during gravitational collapse and stabilisation into new structures will play a key role. First, we show that the static semiclassical counterparts to the Schwarzschild and Reissner–Nordström geometries have singularities which are no longer hidden behind horizons. Then, we argue that in dynamical scenarios of formation and evaporation of black holes, we are left with only three possible outcomes which could avoid singularities and eventual predictability issues. We briefly analyse the viability of each one of them within semiclassical gravity and discuss the expected characteristic timescales of their evolution.


Item Type:Article
Uncontrolled Keywords:quantum fields in curved spacetime; black holes; gravitational collapse; Hawking evaporation; ultracompact stars; semiclassical gravity
Subjects:Sciences > Physics > Astrophysics
Sciences > Physics > Astronomy
Sciences > Physics > Thermodynamics
ID Code:71564
Deposited On:31 Mar 2022 07:52
Last Modified:31 Mar 2022 07:55

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