scholarly journals Entropy of a self-gravitating electrically charged thin shell and the black hole limit

2015 ◽  
Vol 91 (10) ◽  
Author(s):  
José P. S. Lemos ◽  
Gonçalo M. Quinta ◽  
Oleg B. Zaslavskii
2018 ◽  
Vol 27 (11) ◽  
pp. 1843015
Author(s):  
Angel D. D. Masa ◽  
Enesson S. de Oliveira ◽  
Vilson T. Zanchin

The main objective of this work is the construction of regular black hole solutions in the context of the Einstein–Maxwell theory. The strategy is to match an interior regular solution to an exterior electrovacuum solution. With this purpose, we first write explicitly the Einstein field equations for the interior regular region. We take an electrically charged nonisotropic fluid, which presents spherical symmetry and a de Sitter type equation of state, where the radial pressure [Formula: see text] is equal to the negative of energy density [Formula: see text], [Formula: see text]. Then, two solutions for the Einstein equations are built, a regular interior solution for the region with matter satisfying a de Sitter equation of state, and an external solution for the region outside the matter, that corresponds to the Reissner–Nordström metric. To complete the solution we apply the Darmois–Israel junction conditions with a timelike thin shell at the matching surface. It is assumed that the matching surface is composed by a thin shell of matter, i.e. a surface layer in the form of a perfect fluid obeying a barotropic equation of state, [Formula: see text] and [Formula: see text] being the intrinsic pressure and energy density of the shell, respectively, and [Formula: see text] a constant parameter. We show that there are electrically charged regular black hole solutions and other compact objects for specific choices of [Formula: see text] and of the other parameters of the model. Some properties the objects are investigated.


2015 ◽  
Vol 750 ◽  
pp. 306-311 ◽  
Author(s):  
José P.S. Lemos ◽  
Gonçalo M. Quinta ◽  
Oleg B. Zaslavskii

2015 ◽  
Vol 24 (05) ◽  
pp. 1550034 ◽  
Author(s):  
Piyali Bhar ◽  
Ayan Banerjee

In this paper, we construct thin-shell wormholes in (2 + 1)-dimensions from noncommutative BTZ black hole by applying the cut-and-paste procedure implemented by Visser. We calculate the surface stresses localized at the wormhole throat by using the Darmois–Israel formalism and we find that the wormholes are supported by matter violating the energy conditions. In order to explore the dynamical analysis of the wormhole throat, we consider that the matter at the shell is supported by dark energy equation of state (EoS) p = ωρ with ω < 0. The stability analysis is carried out of these wormholes to linearized spherically symmetric perturbations around static solutions. Preserving the symmetry we also consider the linearized radial perturbation around static solution to investigate the stability of wormholes which was explored by the parameter β (speed of sound).


2006 ◽  
Vol 74 (6) ◽  
Author(s):  
Cristián Martínez ◽  
Ricardo Troncoso

2015 ◽  
Vol 360 (1) ◽  
Author(s):  
Jin-Ling Geng ◽  
Yu Zhang ◽  
En-Kun Li ◽  
Peng-Fei Duan

2021 ◽  
Author(s):  
Thomas Berry

<p><b>The central theme of this thesis is the study and analysis of black hole mimickers. The concept of a black hole mimicker is introduced, and various mimicker spacetime models are examined within the framework of classical general relativity. The mimickers examined fall into the classes of regular black holes and traversable wormholes under spherical symmetry. The regular black holes examined can be further categorised as static spacetimes, however the traversable wormhole is allowed to have a dynamic (non-static) throat. Astrophysical observables are calculated for a recently proposed regular black hole model containing an exponential suppression of the Misner-Sharp quasi-local mass. This same regular black hole model is then used to construct a wormhole via the "cut-and-paste" technique. The resulting wormhole is then analysed within the Darmois-Israel thin-shell formalism, and a linearised stability analysis of the (dynamic) wormhole throat is undertaken. Yet another regular black hole model spacetime is proposed, extending a previous work which attempted to construct a regular black hole through a quantum "deformation" of the Schwarzschild spacetime. The resulting spacetime is again analysed within the framework of classical general relativity. </b></p><p>In addition to the study of black hole mimickers, I start with a brief overview of the theory of special relativity where a new and novel result is presented for the combination of relativistic velocities in general directions using quaternions. This is succeed by an introduction to concepts in differential geometry needed for the successive introduction to the theory of general relativity. A thorough discussion of the concept of spacetime singularities is then provided, before analysing the specific black hole mimickers discussed above.</p>


2011 ◽  
Vol 26 (14) ◽  
pp. 999-1007 ◽  
Author(s):  
JERZY MATYJASEK ◽  
KATARZYNA ZWIERZCHOWSKA

Perturbative solutions to the fourth-order gravity describing spherically-symmetric, static and electrically charged black hole in an asymptotically de Sitter universe is constructed and discussed. Special emphasis is put on the lukewarm configurations, in which the temperature of the event horizon equals the temperature of the cosmological horizon.


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.


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