scholarly journals BLACK-HOLE HAVING ELECTRIC HAIRS FOR POSITIVE COSMOLOGICAL CONSTANT Λ>0 ON A COSMIC HORIZON SCALE ~1/√Λ

Author(s):  
Sanjeevan Singha Roy ◽  
Aruna Harikant ◽  
Deep Bhattacharjee

This paper is a technical review for a more deliberate paper (Bhattacharya & Lahiri, 2007) where it has been shown that on a positive cosmological scale with Λ>0 having a cosmic horizon scale ~1/√Λ, there exists the soft electric hairs for the solution having the T_00 components of the stress-energy tensor T_μν i.e., ρ=0 on black hole horizon B_H having the maximum density at black hole singularity B_S where cosmic horizon C_H and black hole horizon B_H has only been considered. KEYWORDS: Black Hole – Cosmic Horizon – TOV Limit – Stress-Energy Tensor – Positive Cosmological Constant

2016 ◽  
Vol 2016 ◽  
pp. 1-13 ◽  
Author(s):  
M. Sharif ◽  
Saadia Mumtaz

The aim of this paper is to construct regular Hayward thin-shell wormholes and analyze their stability. We adopt Israel formalism to calculate surface stresses of the shell and check the null and weak energy conditions for the constructed wormholes. It is found that the stress-energy tensor components violate the null and weak energy conditions leading to the presence of exotic matter at the throat. We analyze the attractive and repulsive characteristics of wormholes corresponding toar>0andar<0, respectively. We also explore stability conditions for the existence of traversable thin-shell wormholes with arbitrarily small amount of fluid describing cosmic expansion. We find that the space-time has nonphysical regions which give rise to event horizon for0<a0<2.8and the wormhole becomes nontraversable producing a black hole. The nonphysical region in the wormhole configuration decreases gradually and vanishes for the Hayward parameterl=0.9. It is concluded that the Hayward and Van der Waals quintessence parameters increase the stability of thin-shell wormholes.


Universe ◽  
2020 ◽  
Vol 6 (10) ◽  
pp. 178
Author(s):  
Kirill Bronnikov ◽  
Sergey Bolokhov ◽  
Milena Skvortsova

We discuss the properties of the previously constructed model of a Schwarzschild black hole interior where the singularity is replaced by a regular bounce, ultimately leading to a white hole. We assume that the black hole is young enough so that the Hawking radiation may be neglected. The model is semiclassical in nature and uses as a source of gravity the effective stress-energy tensor (SET) corresponding to vacuum polarization of quantum fields, and the minimum spherical radius is a few orders of magnitude larger than the Planck length, so that the effects of quantum gravity should still be negligible. We estimate the other quantum contributions to the effective SET, caused by a nontrivial topology of spatial sections and particle production from vacuum due to a nonstationary gravitational field and show that these contributions are negligibly small as compared to the SET due to vacuum polarization. The same is shown for such classical phenomena as accretion of different kinds of matter to the black hole and its further motion to the would-be singularity. Thus, in a clear sense, our model of a semiclassical bounce instead of a Schwarzschild singularity is stable under both quantum and classical perturbations.


2017 ◽  
Vol 118 (14) ◽  
Author(s):  
Adam Levi ◽  
Ehud Eilon ◽  
Amos Ori ◽  
Maarten van de Meent

2008 ◽  
Vol 2008 (09) ◽  
pp. 095-095 ◽  
Author(s):  
Dawood A Kothawala ◽  
S Shankaranarayanan ◽  
L Sriramkumar

2003 ◽  
Vol 91 (5) ◽  
Author(s):  
Eric D. Carlson ◽  
William H. Hirsch ◽  
Benedikt Obermayer ◽  
Paul R. Anderson ◽  
Peter B. Groves

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