Quantum Black Holes and Spacetime Singularities

2018 ◽  
pp. 103-118
Author(s):  
Alessia Benedetta Platania
Keyword(s):  
Black Holes ◽  
Spacetime Singularities

scholarly journals Quantum Black Holes and (Re)Solution of the Singularity

Universe ◽  
2021 ◽  
Vol 7 (12) ◽  
pp. 478
Author(s):  
Roberto Casadio
Keyword(s):  
Black Holes ◽  
General Relativity ◽  
Quantum Theory ◽  
Quantum State ◽  
Spacetime Singularities ◽  
Classical General Relativity ◽  
Spacetime Geometry ◽  
Complete Quantum ◽  
General Conditions

Classical general relativity predicts the occurrence of spacetime singularities under very general conditions. Starting from the idea that the spacetime geometry must be described by suitable states in the complete quantum theory of matter and gravity, we shall argue that this scenario cannot be realised physically since no proper quantum state may contain the infinite momentum modes required to resolve the singularity.

scholarly journals Vacuum Semiclassical Gravity Does Not Leave Space for Safe Singularities

Universe ◽  
2021 ◽  
Vol 7 (8) ◽  
pp. 281
Author(s):  
Julio Arrechea ◽  
Carlos Barceló ◽  
Valentin Boyanov ◽  
Luis J. Garay
Keyword(s):  
Black Holes ◽  
General Relativity ◽  
Gravitational Collapse ◽  
Spacetime Singularities ◽  
Cosmic Censorship ◽  
Semiclassical Gravity ◽  
Strong Cosmic Censorship

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.

scholarly journals RECENT DEVELOPMENTS IN GRAVITATIONAL COLLAPSE AND SPACETIME SINGULARITIES

2011 ◽  
Vol 20 (14) ◽  
pp. 2641-2729 ◽  
Author(s):  
PANKAJ S. JOSHI ◽  
DANIELE MALAFARINA
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Gravitational Collapse ◽  
Spacetime Singularities ◽  
Black Hole Physics ◽  
Naked Singularity ◽  
Theory Of Relativity ◽  
Quantum Theories ◽  
Naked Singularities ◽  
Astrophysical Objects

It is now known that when a massive star collapses under the force of its own gravity, the final fate of such a continual gravitational collapse will be either a black hole or a naked singularity under a wide variety of physically reasonable circumstances within the framework of general theory of relativity. The research of recent years has provided considerable clarity and insight on stellar collapse, black holes and the nature and structure of spacetime singularities. We discuss several of these developments here. There are also important fundamental questions that remain unanswered on the final fate of collapse of a massive matter cloud in gravitation theory, especially on naked singularities which are hypothetical astrophysical objects and on the nature of cosmic censorship hypothesis. These issues have key implications for our understanding on black hole physics today, its astrophysical applications, and for certain basic questions in cosmology and possible quantum theories of gravity. We consider these issues here and summarize recent results and current progress in these directions. The emerging astrophysical and observational perspectives and implications are discussed, with particular reference to the properties of accretion disks around black holes and naked singularities, which may provide characteristic signatures and could help distinguish these objects.

Black holes have ring of truth

Nature ◽  
2002 ◽  
Author(s):  
Philip Ball
Keyword(s):  
Black Holes
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