scholarly journals Black hole solution in the framework of arctan-electrodynamics

2017 ◽  
Vol 26 (08) ◽  
pp. 1750075 ◽  
Author(s):  
S. I. Kruglov
Keyword(s):  
Black Hole ◽  
Black Hole Solution ◽  
De Sitter ◽  
Dimensional Parameter ◽  
Regular Black Hole ◽  
Charged Black Holes ◽  
Classical Stability ◽  
Electric And Magnetic Fields ◽  
Magnetic Mass ◽  
Metric Function

An arctan-electrodynamics coupled with the gravitational field is investigated. We obtain the regular black hole solution that at [Formula: see text] gives corrections to the Reissner–Nordström solution. The corrections to Coulomb’s law at [Formula: see text] are found. We evaluate the mass of the black hole that is a function of the dimensional parameter [Formula: see text] introduced in the model. The magnetically charged black hole was investigated and we have obtained the magnetic mass of the black hole and the metric function at [Formula: see text]. The regular black hole solution is obtained at [Formula: see text] with the de Sitter core. We show that there is no singularity of the Ricci scalar for electrically and magnetically charged black holes. Restrictions on the electric and magnetic fields are found that follow from the requirement of the absence of superluminal sound speed and the requirement of a classical stability.

scholarly journals Charged spherically symmetric Taub–NUT black hole solutions in $f(R)$ gravity

2020 ◽  
Vol 2020 (4) ◽  
Author(s):  
G G L Nashed ◽  
Kazuharu Bamba
Keyword(s):  
General Relativity ◽  
Black Hole ◽  
Free Energy ◽  
Black Hole Solution ◽  
Energy Conditions ◽  
Thermodynamic Quantities ◽  
Spherically Symmetric ◽  
Dimensional Parameter ◽  
Charged Black Holes ◽  
Black Hole Solutions

Abstract $f(R)$ theory is a modification of Einstein’s general relativity which has provided many interesting results in cosmology and astrophysics. To derive a black hole solution in this theory is difficult due to the fact that it contains fourth-order differential equations. In this study, we use the first reliable deviation from general relativity which is given by the quadratic form of $f(R)=R+\beta R^2$, where $\beta$ is a dimensional parameter. We calculate the energy conditions of charged black holes and show that they are all satisfied for the Taub–NUT spacetime. Finally, we study some thermodynamic quantities such as entropy, temperature, specific heat, and Gibbs free energy. The calculations of heat capacity and free energy show that the charged Taub–NUT black hole has positive values, which means that it has thermal stability.

scholarly journals Regular black hole interior spacetime supported by three-form field

2021 ◽  
Vol 81 (4) ◽  
Author(s):  
Mariam Bouhmadi-López ◽  
Che-Yu Chen ◽  
Xiao Yan Chew ◽  
Yen Chin Ong ◽  
Dong-han Yeom
Keyword(s):  
Black Hole ◽  
Energy Condition ◽  
Null Energy Condition ◽  
De Sitter ◽  
Regular Black Hole ◽  
Black Hole Spacetime ◽  
Form Field ◽  
Black Hole Interior ◽  
Metric Function ◽  
Geodesically Complete

AbstractIn this paper, we show that a minimally coupled 3-form endowed with a proper potential can support a regular black hole interior. By choosing an appropriate form for the metric function representing the radius of the 2-sphere, we solve for the 3-form field and its potential. Using the obtained solution, we construct an interior black hole spacetime which is everywhere regular. The singularity is replaced with a Nariai-type spacetime, whose topology is $$\text {dS}_2 \times \text {S}^2$$ dS 2 × S 2 , in which the radius of the 2-sphere is constant. So long as the interior continues to expand indefinitely, the geometry becomes essentially compactified. The 2-dimensional de Sitter geometry appears despite the negative potential of the 3-form field. Such a dynamical compactification could shed some light on the origin of de Sitter geometry of our Universe, exacerbated by the Swampland conjecture. In addition, we show that the spacetime is geodesically complete. The geometry is singularity-free due to the violation of the null energy condition.

Localization of energy for a regular black hole solution in an asymptotically de Sitter spacetime geometry

Open Physics ◽  
2011 ◽  
Vol 9 (5) ◽  
Author(s):  
Irina Radinschi ◽  
Theophanes Grammenos ◽  
Andromahi Spanou
Keyword(s):  
Black Hole ◽  
Black Hole Solution ◽  
Mass Parameter ◽  
De Sitter Spacetime ◽  
De Sitter ◽  
Regular Black Hole ◽  
Spacetime Geometry ◽  
Sitter Spacetime ◽  
Momentum Distributions ◽  
Energy And Momentum

AbstractThe energy and momentum distributions of a regular black hole in a four-dimensional, asymptotically de Sitter spacetime geometry are computed, whereby the Einstein, Landau-Lifshitz, Weinberg and Møller energy-momentum complexes are utilized. It is found, for all prescriptions applied, that the momentum distribution vanishes, while the energy distribution depends on the mass parameter M, the electric charge Q, and the cosmological constant Λ. In addition, various limiting cases are discussed.

scholarly journals Hayward black hole heat engine efficiency in anti-de Sitter space

2021 ◽  
pp. 2150108
Author(s):  
Sen Guo ◽  
Ya Ling Huang ◽  
Ke Jiang He ◽  
Guo Ping Li
Keyword(s):  
Black Hole ◽  
Phase Space ◽  
Magnetic Charge ◽  
Heat Engine ◽  
Extended Phase Space ◽  
De Sitter ◽  
Extended Phase ◽  
Regular Black Hole ◽  
Engine Efficiency ◽  
Thermodynamic Pressure

In this paper, we attempt to further study the heat engine efficiency for the regular black hole (BH) with an anti-de Sitter (AdS) background where the working material is the Hayward–AdS (HAdS) BH. In the extended phase space, we investigate the heat engine efficiency of the HAdS BH by defining the cosmological constant as the thermodynamic pressure P and deriving the mechanical work from the PdV terms. Then, we obtain the relation between the efficiency and the entropy/pressure and plot these function figures. Meanwhile, we compare the relation between the HAdS BH with that of the Bardeen–AdS (BAdS) BH, where it is found that the efficiency of the HAdS BH increases with increase in the magnetic charge q in contrast to that of the BAdS BH decrease with increase in the magnetic charge q. We found that the HAdS BH is more efficient than the BAdS BH, and guess that it is related to the BH structure.

scholarly journals A regular scale-dependent black hole solution

2018 ◽  
Vol 27 (03) ◽  
pp. 1850032 ◽  
Author(s):  
Ernesto Contreras ◽  
Ángel Rincón ◽  
Benjamin Koch ◽  
Pedro Bargueño
Keyword(s):  
General Relativity ◽  
Black Hole ◽  
Black Hole Solution ◽  
Energy Momentum Tensor ◽  
Energy Condition ◽  
Momentum Tensor ◽  
Scale Dependence ◽  
Weak Energy Condition ◽  
Effective Energy ◽  
Regular Black Hole

In this work, we present a regular black hole solution, in the context of scale-dependent General Relativity, satisfying the weak energy condition. The source of this solution is an anisotropic effective energy–momentum tensor which appears when the scale dependence of the theory is turned-on. In this sense, the solution can be considered as a semiclassical extension of the Schwarzschild one.

scholarly journals ORIGIN OF MATTER OUT OF PURE CURVATURE

2008 ◽  
Vol 17 (03n04) ◽  
pp. 513-518 ◽  
Author(s):  
NARESH DADHICH ◽  
HIDEKI MAEDA
Keyword(s):  
Black Hole ◽  
Black Hole Solution ◽  
Space Time ◽  
De Sitter ◽  
Matter Distribution ◽  
Static Black Hole ◽  
Negative Constant ◽  
Usual Formula ◽  
The Universe ◽  
Kaluza Klein

We propose a mechanism for the origin of matter in the universe in the framework of Einstein–Gauss–Bonnet gravity in higher dimensions. The new static black hole solution recently discovered by the authors,1 with the Kaluza–Klein split of space–time as a product of the usual [Formula: see text] with a space of negative constant curvature, is indeed a pure gravitational creation of a black hole which is also endowed with a Maxwell-like gravitational charge in four-dimensional vacuum space–time. This solution has been further generalized to include radially flowing radiation, which means that extra-dimensional curvature also produces matter distribution asymptotically, resembling charged null dust. The static black hole could thus be envisioned as being formed from anti–de Sitter space–time by the collapse of radially inflowing charged null dust. It thus establishes the remarkable reciprocity between matter and gravity — as matter produces gravity (curvature), gravity produces matter. After the Kaluza–Klein generation of the Maxwell field, this is the first instance of realization of matter without matter in the classical framework.

scholarly journals Energy Distribution of a Regular Black Hole Solution in Einstein-Nonlinear Electrodynamics

2015 ◽  
Vol 2015 ◽  
pp. 1-12 ◽  
Author(s):  
I. Radinschi ◽  
F. Rahaman ◽  
Th. Grammenos ◽  
A. Spanou ◽  
Sayeedul Islam
Keyword(s):  
Black Hole ◽  
Positive Integer ◽  
Energy Distribution ◽  
Black Hole Solution ◽  
Mass Function ◽  
Nonlinear Electrodynamics ◽  
Radial Coordinate ◽  
Regular Black Hole ◽  
Limiting Behavior ◽  
Special Case

A study about the energy momentum of a new four-dimensional spherically symmetric, static and charged, regular black hole solution developed in the context of general relativity coupled to nonlinear electrodynamics is presented. Asymptotically, this new black hole solution behaves as the Reissner-Nordström solution only for the particular valueμ=4, whereμis a positive integer parameter appearing in the mass function of the solution. The calculations are performed by use of the Einstein, Landau-Lifshitz, Weinberg, and Møller energy momentum complexes. In all the aforementioned prescriptions, the expressions for the energy of the gravitating system considered depend on the massMof the black hole, its chargeq, a positive integerα, and the radial coordinater. In all these pseudotensorial prescriptions, the momenta are found to vanish, while the Landau-Lifshitz and Weinberg prescriptions give the same result for the energy distribution. In addition, the limiting behavior of the energy for the casesr→∞,r→0, andq=0is studied. The special caseμ=4andα=3is also examined. We conclude that the Einstein and Møller energy momentum complexes can be considered as the most reliable tools for the study of the energy momentum localization of a gravitating system.

scholarly journals A note on Reissner–Nordström black holes in the inverse electrodynamics model

2021 ◽  
pp. 2150155
Author(s):  
S. Habib Mazharimousavi
Keyword(s):  
Black Holes ◽  
General Relativity ◽  
Black Hole ◽  
General Class ◽  
Black Hole Solution ◽  
Energy Momentum Tensor ◽  
Momentum Tensor ◽  
Nonlinear Electrodynamics ◽  
Nonlinear Electrodynamic ◽  
Electric And Magnetic Fields

Recently, the inverse electrodynamics model (IEM) was introduced and applied to find Reissner–Nordström black holes in the context of the general relativity coupled minimally with the nonlinear electrodynamics. The solution consists of both electric and magnetic fields as of the dyonic solutions. Here, in this note, we show that the IEM model belongs to a more general class of the nonlinear electrodynamics with [Formula: see text]. Here, [Formula: see text] is the energy momentum tensor of the nonlinear electrodynamic Lagrangian. Naturally, such a dyonic RN black hole solution is the solution for this general class.

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