scholarly journals Strong cosmic censorship for the massless Dirac field in the Reissner-Nordstrom-de Sitter spacetime

2019 ◽  
Vol 2019 (1) ◽  
Author(s):  
Boxuan Ge ◽  
Jie Jiang ◽  
Bin Wang ◽  
Hongbao Zhang ◽  
Zhen Zhong
Keyword(s):  
Cosmic Censorship ◽  
Dirac Field ◽  
De Sitter Spacetime ◽  
De Sitter ◽  
Sitter Spacetime ◽  
Strong Cosmic Censorship

scholarly journals Strong Cosmic Censorship in higher-dimensional Reissner-Nordström-de Sitter spacetime

2019 ◽  
Vol 2019 (3) ◽  
Author(s):  
Hang Liu ◽  
Ziyu Tang ◽  
Kyriakos Destounis ◽  
Bin Wang ◽  
Eleftherios Papantonopoulos ◽  
...  
Keyword(s):  
Cosmic Censorship ◽  
De Sitter Spacetime ◽  
De Sitter ◽  
Sitter Spacetime ◽  
Strong Cosmic Censorship ◽  
Higher Dimensional

scholarly journals HIGHER DIMENSIONAL INHOMOGENEOUS DUST COLLAPSE AND COSMIC CENSORSHIP

2002 ◽  
Vol 17 (20) ◽  
pp. 2747-2747
Author(s):  
A. BEESHAM
Keyword(s):  
Black Holes ◽  
Cosmic Censorship ◽  
De Sitter Spacetime ◽  
De Sitter ◽  
Naked Singularities ◽  
Singularity Theorems ◽  
Sitter Spacetime ◽  
Higher Dimensional ◽  
Cosmic Censorship Hypothesis ◽  
Strong Curvature

The singularity theorems of general relativity predict that gravitational collapse finally ends up in a spacetime singularity1. The cosmic censorship hypothesis (CCH) states that such a singularity is covered by an event horizon2. Despite much effort, there is no rigorous formulation or proof of the CCH. In view of this, examples that appear to violate the CCH and lead to naked singularities, in which non-spacelike curves can emerge, rather than black holes, are important to shed more light on the issue. We have studied several collapse scenarios which can lead to both situations3. In the case of the Vaidya-de Sitter spacetime4, we have shown that the naked singularities that arise are of the strong curvature type. Both types of singularities can also arise in higher dimensional Vaidya and Tolman-Bondi spacetimes, but black holes are favoured in some sense by the higher dimensions. The charged Vaidya-de Sitter spacetime also exhibits both types of singularities5.

scholarly journals COULOMB SCATTERING OF THE DIRAC FERMIONS ON DE SITTER EXPANDING UNIVERSE

2007 ◽  
Vol 22 (34) ◽  
pp. 2573-2585 ◽  
Author(s):  
COSMIN CRUCEAN
Keyword(s):  
Dirac Equation ◽  
Exact Solutions ◽  
Cross Section ◽  
Dirac Field ◽  
Coulomb Scattering ◽  
De Sitter Spacetime ◽  
Dirac Fermions ◽  
Final States ◽  
De Sitter ◽  
Sitter Spacetime

The lowest order contribution of the amplitude of the Dirac–Coulomb scattering in de Sitter spacetime is calculated assuming that the initial and final states of the Dirac field are described by exact solutions of the free Dirac equation on de Sitter spacetime with a given momentum and helicity. One studies the difficulties that arises when one passes from the amplitude to cross section.

IS THE NAKED SINGULARITY INCOMPATIBLE TO QUANTUM GRAVITY?

2005 ◽  
Vol 20 (24) ◽  
pp. 1823-1829 ◽  
Author(s):  
LI XIANG ◽  
YOU-GEN SHEN
Keyword(s):  
Generalized Uncertainty Principle ◽  
Charged Particles ◽  
Naked Singularity ◽  
Cosmic Censorship ◽  
Second Law ◽  
De Sitter Spacetime ◽  
De Sitter ◽  
Naked Singularities ◽  
Sitter Spacetime ◽  
Cosmic Censorship Hypothesis

In this paper two consequences of the generalized uncertainty principle (GUP) are discussed in a heuristic manner. Both could be regarded as the evidences that prefer the cosmic censorship hypothesis (CCH). The first one is that the second law tends to decline the massless charged particles if the effects of the GUP on the thermodynamics of a de Sitter spacetime are considered. This weakens the threat to the horizon of an extreme charged black hole. The second one is that the uv/ir correspondence provides a constraint on the relation between the energy and the size of a system, which is incompatible to the naked singularities.

scholarly journals Emergent $$\alpha $$-like fermionic vacuum structure and entanglement in the hyperbolic de Sitter spacetime

2019 ◽  
Vol 79 (9) ◽  
Author(s):  
Sourav Bhattacharya ◽  
Shankhadeep Chakrabortty ◽  
Shivang Goyal
Keyword(s):  
Quantum Correlations ◽  
Dirac Field ◽  
De Sitter Spacetime ◽  
De Sitter ◽  
Local Modes ◽  
Vacuum Structure ◽  
Continuous Parameter ◽  
Sitter Spacetime ◽  
Global Modes ◽  
De Sitter Vacua

Abstract We report a non-trivial feature of the vacuum structure of free massive or massless Dirac fields in the hyperbolic de Sitter spacetime. Here we have two causally disconnected regions, say R and L separated by another region, C. We are interested in the field theory in $$R\cup L$$R∪L to understand the long range quantum correlations between R and L. There are local modes of the Dirac field having supports individually either in R or L, as well as global modes found via analytically continuing the R modes to L and vice versa. However, we show that unlike the case of a scalar field, the analytic continuation does not preserve the orthogonality of the resulting global modes. Accordingly, we need to orthonormalise them following the Gram–Schmidt prescription, prior to the field quantisation in order to preserve the canonical anti-commutation relations. We observe that this prescription naturally incorporates a spacetime independent continuous parameter, $$\theta _{\mathrm{RL}}$$θRL, into the picture. Thus interestingly, we obtain a naturally emerging one-parameter family of $$\alpha $$α-like de Sitter vacua. The values of $$\theta _{\mathrm{RL}}$$θRL yielding the usual thermal spectra of massless created particles are pointed out. Next, using these vacua, we investigate both entanglement and Rényi entropies of either of the regions and demonstrate their dependence on $$\theta _{\mathrm{RL}}$$θRL.

scholarly journals REMARKS ON THE SPHERICAL WAVES OF THE DIRAC FIELD ON de SITTER SPACETIME

2006 ◽  
Vol 21 (16) ◽  
pp. 1313-1318 ◽  
Author(s):  
ION I. COTĂESCU ◽  
RADU RACOCEANU ◽  
COSMIN CRUCEAN
Keyword(s):  
Dirac Equation ◽  
Dirac Field ◽  
De Sitter Spacetime ◽  
Moving Frames ◽  
De Sitter ◽  
Spherical Waves ◽  
Commuting Operators ◽  
Quantum Numbers ◽  
Sitter Spacetime

The Shishkin's solutions of the Dirac equation in spherical moving frames of the de Sitter spacetime are investigated pointing out the set of commuting operators whose eigenvalues determine the integration constants. It is shown that these depend on the usual angular quantum numbers and, in addition, on the value of the scalar momentum. With these elements a new result is obtained finding the system of solutions normalized (in generalized sense) in the scale of scalar momentum.

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