scholarly journals Strong cosmic censorship in charged black-hole spacetimes: Still subtle

2018 ◽  
Vol 98 (10) ◽  
Author(s):  
Vitor Cardoso ◽  
João L. Costa ◽  
Kyriakos Destounis ◽  
Peter Hintz ◽  
Aron Jansen
Keyword(s):  
Black Hole ◽  
Cosmic Censorship ◽  
Charged Black Hole ◽  
Black Hole Spacetimes ◽  
Strong Cosmic Censorship

scholarly journals A proof of the strong cosmic censorship conjecture

2020 ◽  
Vol 29 (14) ◽  
pp. 2042003
Author(s):  
Shahar Hod
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Second Law Of Thermodynamics ◽  
Cosmic Censorship ◽  
Necessary Condition ◽  
Deterministic Theory ◽  
Black Hole Spacetimes ◽  
Generalized Second Law ◽  
Strong Cosmic Censorship ◽  
Cosmic Censorship Conjecture

The Penrose strong cosmic censorship conjecture asserts that Cauchy horizons inside dynamically formed black holes are unstable to remnant matter fields that fall into the black holes. The physical importance of this conjecture stems from the fact that it provides a necessary condition for general relativity to be a truly deterministic theory of gravity. Determining the fate of the Penrose conjecture in nonasymptotically flat black hole spacetimes has been the focus of intense research efforts in recent years. In this paper, we provide a remarkably compact proof, which is based on Bekenstein’s generalized second law of thermodynamics, for the validity of the intriguing Penrose conjecture in physically realistic (dynamically formed) curved black hole spacetimes.

scholarly journals Diving inside a hairy black hole

2021 ◽  
Vol 2021 (5) ◽  
Author(s):  
Nicolás Grandi ◽  
Ignacio Salazar Landea
Keyword(s):  
Black Hole ◽  
Cosmic Censorship ◽  
Charged Black Hole ◽  
Cauchy Horizon ◽  
Strong Cosmic Censorship ◽  
Scalar Hair ◽  
Hairy Black Hole ◽  
Cosmic Censorship Conjecture

Abstract We investigate the interior of the Einstein-Gauss-Bonnet charged black-hole with scalar hair. We find a variety of dynamical epochs, with the particular important feature that the Cauchy horizon is not present. This makes the violation of the no-hair theorem a possible tool to understand how might the strong cosmic censorship conjecture work.

scholarly journals Magnetized Reissner–Nordström black hole restores cosmic censorship conjecture

2019 ◽  
Vol 49 ◽  
pp. 1960020 ◽  
Author(s):  
Sanjar Shaymatov
Keyword(s):  
Magnetic Field ◽  
Black Hole ◽  
Threshold Value ◽  
Cosmic Censorship ◽  
Black Hole Horizon ◽  
Charged Black Hole ◽  
The Magnetic Field ◽  
Cosmic Censorship Conjecture

We investigate the effect of magnetic field on the process of overcharging magnetized Reissner–Nordström black hole. It is well known that a four dimensional charged black hole could be overcharged. Contrary to this, we show that a magnetized charged black hole could not be overcharged beyond threshold value of the magnetic field. This occurs because the magnetic field does not allow for particle to reach black hole horizon. Thus magnetic field beyond its threshold value could restore the cosmic censorship conjecture.

scholarly journals Diophantine approximation as Cosmic Censor for Kerr–AdS black holes

2021 ◽  
Author(s):  
Christoph Kehle
Keyword(s):  
Black Hole ◽  
Diophantine Approximation ◽  
Blow Up ◽  
Cosmic Censorship ◽  
Resonance Phenomenon ◽  
Diophantine Condition ◽  
Cauchy Horizon ◽  
Strong Cosmic Censorship ◽  
Linear Scalar ◽  
Scalar Perturbations

AbstractThe purpose of this paper is to show an unexpected connection between Diophantine approximation and the behavior of waves on black hole interiors with negative cosmological constant $$\Lambda <0$$ Λ < 0 and explore the consequences of this for the Strong Cosmic Censorship conjecture in general relativity. We study linear scalar perturbations $$\psi $$ ψ of Kerr–AdS solving $$\Box _g\psi -\frac{2}{3}\Lambda \psi =0$$ □ g ψ - 2 3 Λ ψ = 0 with reflecting boundary conditions imposed at infinity. Understanding the behavior of $$\psi $$ ψ at the Cauchy horizon corresponds to a linear analog of the problem of Strong Cosmic Censorship. Our main result shows that if the dimensionless black hole parameters mass $${\mathfrak {m}} = M \sqrt{-\Lambda }$$ m = M - Λ and angular momentum $${\mathfrak {a}} = a \sqrt{-\Lambda }$$ a = a - Λ satisfy a certain non-Diophantine condition, then perturbations $$\psi $$ ψ arising from generic smooth initial data blow up $$|\psi |\rightarrow +\infty $$ | ψ | → + ∞ at the Cauchy horizon. The proof crucially relies on a novel resonance phenomenon between stable trapping on the black hole exterior and the poles of the interior scattering operator that gives rise to a small divisors problem. Our result is in stark contrast to the result on Reissner–Nordström–AdS (Kehle in Commun Math Phys 376(1):145–200, 2020) as well as to previous work on the analogous problem for $$\Lambda \ge 0$$ Λ ≥ 0 —in both cases such linear scalar perturbations were shown to remain bounded. As a result of the non-Diophantine condition, the set of parameters $${\mathfrak {m}}, {\mathfrak {a}}$$ m , a for which we show blow-up forms a Baire-generic but Lebesgue-exceptional subset of all parameters below the Hawking–Reall bound. On the other hand, we conjecture that for a set of parameters $${\mathfrak {m}}, {\mathfrak {a}} $$ m , a which is Baire-exceptional but Lebesgue-generic, all linear scalar perturbations remain bounded at the Cauchy horizon $$|\psi |\le C$$ | ψ | ≤ C . This suggests that the validity of the $$C^0$$ C 0 -formulation of Strong Cosmic Censorship for $$\Lambda <0$$ Λ < 0 may change in a spectacular way according to the notion of genericity imposed.

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