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Vacuum Semiclassical Gravity Does Not Leave Space for Safe Singularities

Authors :
Julio Arrechea
Carlos Barceló
Valentin Boyanov
Luis J. Garay
Source :
Universe, Vol 7, Iss 8, p 281 (2021)
Publication Year :
2021
Publisher :
MDPI AG, 2021.

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.

Details

Language :
English
ISSN :
22181997
Volume :
7
Issue :
8
Database :
Directory of Open Access Journals
Journal :
Universe
Publication Type :
Academic Journal
Accession number :
edsdoj.3363633722d04bb8a9161665712c402a
Document Type :
article
Full Text :
https://doi.org/10.3390/universe7080281