scholarly journals Spatially homogeneous black hole solutions in $$z=4$$ Hořava–Lifshitz gravity in $$(4+1)$$ dimensions with Nil geometry and $$H^2\times R$$ horizons

2021 ◽  
Vol 81 (10) ◽  
Author(s):  
F. Naderi ◽  
A. Rezaei-Aghdam ◽  
Z. Mahvelati-Shamsabadi
Keyword(s):  
Black Hole ◽  
Black Hole Solution ◽  
Three Dimensional ◽  
Hamiltonian Formalism ◽  
Coupling Constant ◽  
Especial Case ◽  
Gravity Equations ◽  
Spatially Homogeneous ◽  
Black Hole Solutions ◽  
Bianchi Types

AbstractIn this paper, we present two new families of spatially homogeneous black hole solution for $$z=4$$ z = 4 Hořava–Lifshitz Gravity equations in $$(4+1)$$ ( 4 + 1 ) dimensions with general coupling constant $$\lambda $$ λ and the especial case $$\lambda =1$$ λ = 1 , considering $$\beta =-1/3$$ β = - 1 / 3 . The three-dimensional horizons are considered to have Bianchi types II and III symmetries, and hence the horizons are modeled on two types of Thurston 3-geometries, namely the Nil geometry and $$H^2\times R$$ H 2 × R . Being foliated by compact 3-manifolds, the horizons are neither spherical, hyperbolic, nor toroidal, and therefore are not of the previously studied topological black hole solutions in Hořava–Lifshitz gravity. Using the Hamiltonian formalism, we establish the conventional thermodynamics of the solutions defining the mass and entropy of the black hole solutions for several classes of solutions. It turned out that for both horizon geometries the area term in the entropy receives two non-logarithmic negative corrections proportional to Hořava–Lifshitz parameters. Also, we show that choosing some proper set of parameters the solutions can exhibit locally stable or unstable behavior.

scholarly journals New five-dimensional Bianchi type magnetically charged hairy topological black hole solutions in string theory

2019 ◽  
Vol 79 (12) ◽  
Author(s):  
F. Naderi ◽  
A. Rezaei-Aghdam
Keyword(s):  
Black Hole ◽  
Black Hole Solution ◽  
Bianchi Type ◽  
Magnetic Charge ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Five Dimensions ◽  
Asymptotically Flat ◽  
Black Hole Solutions ◽  
Three Dimensional Space

AbstractWe construct black hole solutions to the leading order of string effective action in five dimensions with the source given by dilaton and magnetically charged antisymmetric gauge B-field. Presence of the considered B-field leads to the unusual asymptotic behavior of the solutions which are neither asymptotically flat nor asymptotically (A)dS. We consider the three-dimensional space part to correspond to the Bianchi classes and so the horizons of these topological black hole solutions are modeled by seven homogeneous Thurston’s geometries of $$E^3$$E3, $$S^3$$S3, $$H^3$$H3, $$ H^2 \times E^1$$H2×E1, $$\widetilde{{SL_2R}}$$SL2R~, nilgeometry, and solvegeometry. Calculating the quasi-local mass, temperature, entropy, dilaton charge, and magnetic potential, we show that the first law of black hole thermodynamics is satisfied by these quantities and the dilaton charge is not independent of mass and magnetic charge. Furthermore, for Bianchi type V, the T-dual black hole solution is obtained which carries no charge associated with B-field and the entropy turns to be invariant under the T-duality.

scholarly journals Causality of black holes in 4-dimensional Einstein–Gauss–Bonnet–Maxwell theory

2020 ◽  
Vol 80 (8) ◽  
Author(s):  
Xian-Hui Ge ◽  
Sang-Jin Sin
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Shear Viscosity ◽  
Upper Bound ◽  
Causal Structure ◽  
Density Ratio ◽  
Entropy Density ◽  
Coupling Constant ◽  
Maxwell Theory ◽  
Black Hole Solutions

Abstract We study charged black hole solutions in 4-dimensional (4D) Einstein–Gauss–Bonnet–Maxwell theory to the linearized perturbation level. We first compute the shear viscosity to entropy density ratio. We then demonstrate how bulk causal structure analysis imposes an upper bound on the Gauss–Bonnet coupling constant in the AdS space. Causality constrains the value of Gauss–Bonnet coupling constant $$\alpha _{GB}$$αGB to be bounded by $$\alpha _{GB}\le 0$$αGB≤0 as $$D\rightarrow 4$$D→4.

scholarly journals Hairy black hole solutions in a three-dimensional Galileon model

2018 ◽  
Vol 35 (18) ◽  
pp. 185010 ◽  
Author(s):  
Gérard Clément ◽  
Khireddine Nouicer
Keyword(s):  
Black Hole ◽  
Three Dimensional ◽  
Black Hole Solutions ◽  
Hairy Black Hole

scholarly journals Constructing black hole solutions in supergravity theories

2019 ◽  
Vol 34 (35) ◽  
pp. 1930017 ◽  
Author(s):  
Antonio Gallerati
Keyword(s):  
Black Holes ◽  
General Relativity ◽  
Black Hole ◽  
Supergravity Models ◽  
Detailed Analysis ◽  
Black Hole Solution ◽  
Explicit Construction ◽  
General Introduction ◽  
Supersymmetric Theories ◽  
Black Hole Solutions

We perform a detailed analysis of black hole solutions in supergravity models. After a general introduction on black holes in general relativity and supersymmetric theories, we provide a detailed description of ungauged extended supergravities and their dualities. Therefore, we analyze the general form of black hole configurations for these models, their near-horizon behavior and characteristic of the solution. An explicit construction of a black hole solution with its physical implications is given for the STU-model. The second part of this review is dedicated to gauged supergravity theories. We describe a step-by-step gauging procedure involving the embedding tensor formalism to be used to obtain a gauged model starting from an ungauged one. Finally, we analyze general black hole solutions in gauged models, providing an explicit example for the [Formula: see text], [Formula: see text] case. A brief review on special geometry is also provided, with explicit results and relations for supersymmetric black hole solutions.

scholarly journals Black holes in magnetic monopoles with a dark halo

2019 ◽  
Vol 34 (01) ◽  
pp. 1950002 ◽  
Author(s):  
A. Lugo ◽  
J. M. Pérez Ipiña ◽  
F. A. Schaposnik
Keyword(s):  
Black Hole ◽  
Black Hole Solution ◽  
Scalar Potential ◽  
Magnetic Monopoles ◽  
Dark Halo ◽  
Higgs Potential ◽  
Coupling Constant ◽  
Horizon Radius ◽  
Yang Mills ◽  
Higgs Portal

We study a spontaneously broken Einstein–Yang–Mills–Higgs model coupled via a Higgs portal to an uncharged scalar [Formula: see text]. We present a phase diagram of self-gravitating solutions showing that depending on the choice of parameters of the [Formula: see text] scalar potential and the Higgs portal coupling constant [Formula: see text], one can identify different regions: If [Formula: see text] is sufficiently small, a [Formula: see text] halo is created around the monopole core which in turn surrounds a black hole. For larger values of [Formula: see text], no halo exists and the solution is just a black hole monopole one. When the horizon radius grows and becomes larger than the monopole radius, solely a black hole solution exists. Because of the presence of the [Formula: see text] scalar, a bound for the Higgs potential coupling constant exists and when it is not satisfied, the vacuum is unstable and no nontrivial solution exists. We briefly comment on possible connections of our results with those found in recent dark matter axion models.

scholarly journals Exact black hole solutions with nonlinear electrodynamic field

2020 ◽  
Vol 29 (05) ◽  
pp. 2050032
Author(s):  
Shuang Yu ◽  
Changjun Gao
Keyword(s):  
Black Hole ◽  
Cosmological Constant ◽  
Electric Charge ◽  
Single Phase ◽  
Causal Structure ◽  
Nonlinear Electrodynamic ◽  
Coupling Constant ◽  
De Sitter ◽  
Black Hole Solutions ◽  
Three Phases

We construct exact black hole solutions to Einstein gravity with nonlinear electrodynamic field. In these solutions, there are, in general, four parameters. They are physical mass, electric charge, cosmological constant and the coupling constant. These solutions differ significantly from the Reissner–Nordström–de Sitter solution in Einstein–Maxwell gravity with a cosmological constant, due to the presence of coupling constant. For example, some of them are endowed with a topological defect on angle [Formula: see text] and the electric charge of some can be much larger or smaller than their mass by varying the coupling constant. On the other hand, these spacetimes are all asymptotically de Sitter (or anti-de Sitter). As a result, their causal structure is similar to the Reissner–Nordström–de Sitter spacetime. Finally, the investigations on the thermodynamics reveal that the coupling constant except for solution-4 has the opposite effect as temperature on the phase, structure of black holes. Concretely, the phase-space changes from single phase to three phases with the decrease of temperature. On the contrary, it changes from three phases to a single phase with the decrease of coupling constant.

BLACK HOLE THERMODYNAMIC FLUCTUATIONS AND PHASE TRANSITION OF IR MODIFIED HOŘAVA–LIFSHITZ GRAVITY

2014 ◽  
Vol 23 (03) ◽  
pp. 1450027
Author(s):  
SHIWEI ZHOU ◽  
ZHENFENG NIU ◽  
YAN LÜ
Keyword(s):  
Phase Transition ◽  
Black Hole ◽  
Black Hole Solution ◽  
Three Dimensional ◽  
Nonequilibrium Thermodynamic ◽  
3D Geometry ◽  
Lifshitz Theory ◽  
The Common ◽  
Renormalizable Model ◽  
Relevant Operator

Hořava–Lifshitz theory as a renormalizable model of gravity might be an ultraviolet (UV) completion of general relativity (GR) and it reduces to Einstein gravity with a nonvanishing cosmological constant in infrared (IR) approximation. Kehagias and Sfetsos have added a relevant operator proportional to the three-dimensional (3D) geometry Ricci scalar to the original Hořava–Lifshitz theory action and obtained a spherically symmetric asymptotically flat black hole solution called Kehagias–Sfetsos (KS) black hole. Nonequilibrium thermodynamic fluctuations based on the metric of a KS black hole in IR modified Hořava–Lifshitz gravity have been calculated. It is concluded that the second-order momentum of mass flux is nondivergent and phase transition does not occur at the extremal case, while phase transition occurs at some other case, which is also different from the common case when the heat capacity is divergent.

scholarly journals Exact charged black hole solutions in D-dimensions in f(R) gravity

2021 ◽  
Vol 81 (4) ◽  
Author(s):  
Zi-Yu Tang ◽  
Bin Wang ◽  
Eleftherios Papantonopoulos
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
General Solution ◽  
Constant Curvature ◽  
Black Hole Solution ◽  
Einstein Gravity ◽  
Charged Black Hole ◽  
Spherically Symmetric ◽  
Spherically Symmetric Metric ◽  
Black Hole Solutions

AbstractWe consider Maxwell-f(R) gravity and obtain an exact charged black hole solution with dynamic curvature in D-dimensions. Considering a spherically symmetric metric ansatz and without specifying the form of f(R) we find a general black hole solution in D-dimensions. This general black hole solution can reduce to the Reissner–Nordström (RN) black hole in D-dimensions in Einstein gravity and to the known charged black hole solutions with constant curvature in f(R) gravity. Restricting the parameters of the general solution we get polynomial solutions which reveal novel properties when compared to RN black holes. Specifically we study the solution in $$(3+1)$$ ( 3 + 1 ) -dimensions in which the form of f(R) can be solved explicitly giving a dynamic curvature and compare it with the RN black hole. We also carry out a detailed study of its thermodynamics.

Three-dimensional slowly rotating black hole in Einstein-power-Maxwell theory

2020 ◽  
pp. 2050111
Author(s):  
M. B. Tataryn ◽  
M. M. Stetsko
Keyword(s):  
Magnetic Field ◽  
Black Hole ◽  
Black Hole Solution ◽  
Three Dimensional ◽  
Integral Solution ◽  
Static Case ◽  
Maxwell Theory ◽  
Rotating Black Hole ◽  
Metric Function ◽  
Small Rotation

A three-dimensional slowly rotating black hole solution in the presence of negative cosmological constant in the Einstein-power-Maxwell theory is studied. It is shown that in the small rotation limit, the electric field, diagonal metric function and thermodynamic properties are the same as for static case, whereas the small rotation gives in addition a nondiagonal metric function and magnetic field which are also small. For these functions cased by rotation of black hole, exact integral solution and analytic asymptotic solution were obtained.

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