scholarly journals Schwarzschild black hole can also produce super-radiation phenomena and the cosmic censorship conjecture may be violated

2021 ◽  
Author(s):  
Wen-Xiang Chen
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Incident Wave ◽  
Bose Condensation ◽  
Cosmic Censorship ◽  
Schwarzschild Black Hole ◽  
Natural Unit ◽  
Potential Barriers ◽  
Unit System ◽  
Cosmic Censorship Conjecture

This article points out that when the boundary conditions$\frac{T}{T_{c}}=z$ (when z is plural) are preset, bosons can produce Bose condensation without an energy layer. Under Bose condensation, the incident wave may condense in the Schwarzschild black hole. At that time, the Schwarzschild black hole event horizon Potential barriers can be generated nearby, and we think that Schwarzschild black holes can also generate superradiation phenomena(This article uses the natural unit system).This implies that the cosmic censorship conjecture may be violated.

scholarly journals Evidence for loop quantum gravity

2021 ◽  
Author(s):  
Wen-Xiang Chen
Keyword(s):  
Black Holes ◽  
Quantum Gravity ◽  
Loop Quantum Gravity ◽  
Bose Condensation ◽  
Traditional Theory ◽  
Natural Unit ◽  
Simple Loop ◽  
Potential Barriers ◽  
Unit System ◽  
Incident Waves

This article points out that when the boundary condition $\frac{T}{T_{c}}=z$ (when z is a complex number) is preset, bosons can produce Bose condensation without an energy layer. Under Bose condensation, incident waves may condense in various black holes in the theory of loop quantum gravity. At that time, potential barriers will be generated near the horizon of various black holes, and we believe that these black holes will also produce super-radiation phenomena (this article uses the natural unit system). We assume that the simple loop quantum gravity theoretical model that can produce superradiation phenomena that does not exist in the traditional theory provides experimental evidence for loop quantum gravity.

The effect of dark matter on the weak cosmic censorship conjecture in the extended space

2021 ◽  
pp. 2150207
Author(s):  
Zi-Yu Fu ◽  
Bao-Qi Zhang ◽  
Chuan-Yin Wang ◽  
Hui-Ling Li
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Dark Matter ◽  
Second Law Of Thermodynamics ◽  
Cosmic Censorship ◽  
De Sitter ◽  
Extended Phase ◽  
Extended Space ◽  
Extreme Black Holes ◽  
Cosmic Censorship Conjecture

By analyzing the energy–momentum relationship of the absorbed fermions dropping into a Reissner–Nordstöm–anti-de Sitter black hole surrounded by dark matter, the laws of thermodynamic and weak cosmic censorship conjecture in the extended phase space are investigated. We find that the first law of thermodynamics is valid. However, the validity of the second law of thermodynamics depends on the density [Formula: see text] of the perfect fluid dark matter. In addition, we also find that when the fermions are absorbed, the structures of black hole surrounded by dark matter would not change. Therefore, weak cosmic censorship conjecture holds for the extreme black holes and the non-extreme black holes.

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 The weak cosmic censorship conjecture may be violated

2020 ◽  
Author(s):  
Wen-Xiang Chen
Keyword(s):  
Black Hole ◽  
Wave Function ◽  
Boundary Conditions ◽  
Cosmic Censorship ◽  
Traditional Theory ◽  
Schwarzschild Black Hole ◽  
Entropy Reduction ◽  
Set Up ◽  
Coupled Wave ◽  
Cosmic Censorship Conjecture

According to traditional theory, the Schwarzschild black hole does not produce superradiation. If the boundary conditions are set up in advance, this possibility will be combined with the boson-coupled wave function in the Schwarzschild black hole, where the incident boson will have a mirrored mass, so even the Schwarzschild black hole can generate superradiation phenomena.Recently, an article of mine obtained interesting results about the Schwarzschild black hole can generate superradiation phenomena. The result contains some conclusions that violate the "no-hair theorem". We know that the phenomenon of black hole superradiation is a process of entropy reduction I found that the weak cosmic censorship conjecture may be violated.

scholarly journals Weak cosmic censorship conjecture in Kerr black holes of modified gravity

2019 ◽  
Vol 34 (05) ◽  
pp. 1950037 ◽  
Author(s):  
Bin Liang ◽  
Shao-Wen Wei ◽  
Yu-Xiao Liu
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Lower Energy ◽  
Energy Gap ◽  
Naked Singularity ◽  
Cosmic Censorship ◽  
Point Particle ◽  
Adiabatic Process ◽  
Energy Bounds ◽  
Cosmic Censorship Conjecture

By neglecting the effects of self-force and radiation, we investigate the possibility of destroying the Kerr-MOG black hole through the point particle absorption process. Using the instability of event horizon and equation of particle motion, we get the upper and lower energy bounds allowed for a matter particle to produce the naked singularity. We find that the energy gap always exists between the upper and lower energy bounds for both extremal and near-extremal black holes, which means some tailored particles can actually lead to the violation of the weak cosmic censorship conjecture. However, when considering the effect of the adiabatic process, the result shows that the Kerr-MOG black hole gets more stable instead of a naked singularity, and thus the weak cosmic censorship conjecture can be restored at some level.

scholarly journals Testing cosmic censorship conjecture near extremal black holes with cosmological constants

2014 ◽  
Vol 23 (05) ◽  
pp. 1450044 ◽  
Author(s):  
Yuan Zhang ◽  
Sijie Gao
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Test Particle ◽  
Kerr Black Hole ◽  
Radiation Reaction ◽  
Cosmic Censorship ◽  
De Sitter ◽  
Test Particles ◽  
Cosmological Constants ◽  
Cosmic Censorship Conjecture

It has been shown previously that an extremal Reissner–Nordström or an extremal Kerr black hole cannot be overcharged or overspun by a test particle, if radiative and self-force effects are neglected. In this paper, we consider extremal charged and rotating black holes with cosmological constants. By studying the motion of test particles, we find the following results: An extremal Reissner–Nordström anti-de Sitter (RN–AdS) black hole can be overcharged by a test particle but an extremal Reissner–Nordström de Sitter (RN–dS) black hole cannot be overcharged. We also show that both extremal Kerr–de Sitter (Kerr–dS) and Kerr–anti-de Sitter (Kerr–AdS) black holes can be overspun by a test particle, implying a possible breakdown of the cosmic censorship conjecture. For the Kerr–AdS case, the overspinning requires that the energy of the particle be negative, a reminiscent of the Penrose process. In contrast to the extremal RN and Kerr black holes, in which cases the cosmic censorship is upheld, our results suggest some subtle relations between the cosmological constants and the cosmic censorship. We also discuss the effect of radiation reaction for the Kerr–dS case and find that the magnitude of energy loss due to gravitational radiation may not be enough to prevent the violation of the cosmic censorship.

scholarly journals Weak cosmic censorship conjecture for the novel 4D charged Einstein–Gauss–Bonnet black hole with test scalar field and particle

2020 ◽  
Vol 80 (10) ◽  
Author(s):  
Si-Jiang Yang ◽  
Jun-Jie Wan ◽  
Jing Chen ◽  
Jie Yang ◽  
Yong-Qiang Wang
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Charged Particle ◽  
Scalar Field ◽  
Cosmic Censorship ◽  
Extremal Black Hole ◽  
The Novel ◽  
Coupling Constant ◽  
Particle Injection ◽  
Cosmic Censorship Conjecture

AbstractRecent researches of the novel 4D Einstein–Gauss–Bonnet (EGB) gravity have attracted great attention. In this paper, we investigate the validity of the weak cosmic censorship conjecture for a novel 4D charged EGB black hole with test charged scalar field and test charged particle respectively. For the test charged field scattering process, we find that both extremal and near-extremal black holes cannot be overcharged. For the test charged particle injection, to first order, an extremal black hole cannot be overcharged while a near-extremal 4D charged EGB black hole can be destroyed. To second order, however, both extremal and near-extremal 4D charged EGB black holes can be overcharged for positive Gauss–Bonnet coupling constant; for negative Gauss–Bonnet coupling constant, an extremal black hole cannot be overcharged and the validity of the weak cosmic censorship conjecture for a near-extremal black hole depends on the Gauss–Bonnet coupling constant.

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