scholarly journals Spherically symmetric charged black holes with wavy scalar hair

2021 ◽  
Author(s):  
Yves Brihaye ◽  
Betti Hartmann
Keyword(s):  
Black Holes ◽  
Electromagnetic Coupling ◽  
Spherically Symmetric ◽  
Gravitational Coupling ◽  
The Novel ◽  
Maxwell Theory ◽  
Charged Black Holes ◽  
Scalar Hair ◽  
Complex Valued ◽  
Black Hole Solutions

Abstract We study standard Einstein-Maxwell theory minimally coupled to a complex valued and self-interacting scalar field. We demonstrate that new, previously unnoticed spherically symmetric, charged black hole solutions with scalar hair exist in this model for sufficiently large gravitational coupling and sufficiently small electromagnetic coupling. The novel scalar hair has the form of a spatially oscillating “wave packet” and back-reacts on the space-time such that both the Ricci and the Kretschmann scalar, respectively, possess qualitatively similar oscillations.

scholarly journals Spherically Symmetric Scalar Hair for Charged Black Holes

2020 ◽  
Vol 125 (11) ◽  
Author(s):  
Jeong-Pyong Hong ◽  
Motoo Suzuki ◽  
Masaki Yamada
Keyword(s):  
Black Holes ◽  
Spherically Symmetric ◽  
Charged Black Holes ◽  
Scalar Hair

scholarly journals Gravitating Cho–Maison monopole

2021 ◽  
Vol 81 (10) ◽  
Author(s):  
Khai-Ming Wong ◽  
Dan Zhu ◽  
Guo-Quan Wong
Keyword(s):  
Black Holes ◽  
Numerical Solutions ◽  
Flat Space ◽  
Spherically Symmetric ◽  
Gravitational Coupling ◽  
Yang Mills ◽  
Charged Black Holes ◽  
Monopole Solution

AbstractWe study numerical solutions corresponding to spherically symmetric gravitating electroweak monopole and magnetically charged black holes of the Einstein–Weinberg–Salam theory. The gravitating electroweak monopole solutions are quite identical to the gravitating monopole solution in SU(2) Einstein–Yang–Mills–Higgs theory, but with distinctive characteristics. We also found solutions representing radially excited monopole, which has no counterpart in flat space. Both of these solutions exist up to a maximal gravitational coupling before they cease to exist. Lastly we also report on magnetically charged non-Abelian black holes solutions that is closely related to the regular monopole solutions, which represents counterexample to the ‘no-hair’ conjecture.

scholarly journals A Smarr formula for charged black holes in nonlinear electrodynamics

2017 ◽  
Vol 32 (39) ◽  
pp. 1750219 ◽  
Author(s):  
Leonardo Balart ◽  
Sharmanthie Fernando
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
General Formula ◽  
Energy Momentum Tensor ◽  
Momentum Tensor ◽  
Nonlinear Electrodynamics ◽  
Spherically Symmetric ◽  
Charged Black Holes ◽  
Electrically Charged ◽  
Black Hole Solutions

It is well known that the Smarr formula does not hold for black holes in nonlinear electrodynamics. The main reason for this is the fact that the trace of the energy–momentum tensor for nonlinear electrodynamics does not vanish as it is for Maxwell’s electrodynamics. Starting from the Komar integral, we derived a new Smarr-type formula for spherically symmetric static electrically charged black hole solutions in nonlinear electrodynamics. We show that this general formula is in agreement with some that are obtained for black hole solutions with nonlinear electrodynamics.

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 ENTROPY OF EXTREMAL DYONIC BLACK HOLES

1996 ◽  
Vol 11 (37) ◽  
pp. 2933-2939 ◽  
Author(s):  
A. GHOSH ◽  
P. MITRA
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
String Theory ◽  
Extremal Black Hole ◽  
Classical Action ◽  
Charged Black Holes ◽  
Thermodynamic Entropy ◽  
Black Hole Solutions

For extremal charged black holes, the thermodynamic entropy is proportional to the mass or charges but not proportional to the area. This is demonstrated here for dyonic extremal black hole solutions of string theory. It is pointed out that these solutions have zero classical action although the area is nonzero. By combining the general form of the entropy allowed by thermodynamics with recent observations in the literature it is possible to fix the entropy almost completely.

scholarly journals Asymptotically Lifshitz black hole solutions in F(R) gravity

2014 ◽  
Vol 92 (1) ◽  
pp. 76-81 ◽  
Author(s):  
S.H. Hendi ◽  
B. Eslam Panah ◽  
C. Corda
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Symmetric Space ◽  
Invariant Theory ◽  
Matter Field ◽  
Spherically Symmetric ◽  
Pure Gravity ◽  
Lifshitz Black Holes ◽  
Lifshitz Black Hole ◽  
Black Hole Solutions

We consider a class of spherically symmetric space–time to obtain some interesting solutions in F(R) gravity without matter field (pure gravity). We investigate the geometry of the solutions and find that there is an essential singularity at the origin. In addition, we show that there is an analogy between obtained solutions with the black holes of Einstein-Λ-power Maxwell invariant theory. Furthermore, we find that these solutions are equivalent to the asymptotically Lifshitz black holes. Also, we calculate d2F/dR2 to examine the Dolgov–Kawasaki stability criterion.

scholarly journals ECO-spotting: looking for extremely compact objects with bosonic fields

2021 ◽  
Author(s):  
Vitor Cardoso ◽  
Caio F. B. Macedo ◽  
Kei-ichi Maeda ◽  
Hirotada Okawa
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Compact Objects ◽  
Spherically Symmetric ◽  
Initial Value ◽  
Flat Spacetime ◽  
The Universe ◽  
Well Posed ◽  
Black Hole Solutions ◽  
Hairy Black Hole

Abstract Black holes are thought to describe the geometry of massive, dark compact objects in the universe. To further support and quantify this long-held belief requires knowledge of possible, if exotic alternatives. Here, we wish to understand how compact can self-gravitating solutions be. We discuss theories with a well-posed initial value problem, consisting in either a single self-interacting scalar, vector or both. We focus on spherically symmetric solutions, investigating the influence of self-interacting potentials into the compactness of the solutions, in particular those that allow for flat-spacetime solutions. We are able to connect such stars to hairy black hole solutions, which emerge as a zero-mass black hole. We show that such stars can have light rings, but their compactness is never parametrically close to that of black holes. The challenge of finding black hole mimickers to investigate full numerical-relativity binary setups remains open.

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.

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