scholarly journals Peculiar five-dimensional black holes

2019 ◽  
Vol 17 (1, spec.issue) ◽  
pp. 69-78
Author(s):  
Dejan Simic
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Semiclassical Approximation ◽  
Three Dimensions ◽  
Spherically Symmetric ◽  
Btz Black Hole ◽  
Lovelock Gravity ◽  
Zero Entropy ◽  
Symmetric Black Hole ◽  
Black Hole Solutions

In this article, we review two black hole solutions to the five-dimensional Lovelock gravity. These solutions are characterized by the non-vanishing torsion and the peculiar property that all their conserved charges vanish. The first solution is a spherically symmetric black hole with torsion, which also has zero entropy in the semiclassical approximation. The second solution is a black ring, which is the five-dimensional uplift of the BTZ black hole with torsion in three dimensions.

scholarly journals Black hole thermodynamics and heat engines in conformal gravity

2017 ◽  
Vol 26 (13) ◽  
pp. 1750151 ◽  
Author(s):  
Hao Xu ◽  
Yuan Sun ◽  
Liu Zhao
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Black Hole Thermodynamics ◽  
Spherically Symmetric ◽  
Conformal Gravity ◽  
Extended Phase ◽  
Heat Engines ◽  
Equation Of States ◽  
Symmetric Black Hole ◽  
Black Hole Solutions

The extended phase-space thermodynamics and heat engines for static spherically symmetric black hole solutions of four-dimensional conformal gravity are studied in detail. It is argued that the equation of states (EOS) for such black holes is always branched, any continuous thermodynamical process cannot drive the system from one branch of the EOS into another branch. Meanwhile, the thermodynamical volume is bounded from above, making the black holes always super-entropic in one branch and may also be super-entropic in another branch in certain range of the temperature. The Carnot and Stirling heat engines associated to such black holes are shown to be distinct from each other. For rectangular heat engines, the efficiency always approaches zero when the rectangle becomes extremely narrow, and given the highest and lowest working temperatures fixed, there is always a maximum for the efficiency of such engines.

scholarly journals Thermodynamics of spherically symmetric black holes in scale-dependent gravity

2020 ◽  
Vol 80 (12) ◽  
Author(s):  
P. Bargueño ◽  
J. A. Miralles ◽  
J. A. Pons
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Spatial Variation ◽  
Gravitational Constant ◽  
Spherically Symmetric ◽  
Equilibrium Thermodynamics ◽  
First Law Of Thermodynamics ◽  
Symmetric Black Hole ◽  
Black Hole Solutions

AbstractIn this work we extend the first law of thermodynamics to spherically symmetric black hole solutions in the context of scale-dependent gravity. After deriving generalized expressions for both the entropy and energy due to the spatial variation of the gravitational constant we analize, by pointing out some relations between scale-dependent and f(R) theories, whether or not the former can be described using equilibrium thermodynamics.

scholarly journals Black Holes with Short Hair

1997 ◽  
Vol 06 (05) ◽  
pp. 563-573 ◽  
Author(s):  
J. David Brown ◽  
Viqar Husain
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Einstein Gravity ◽  
Spherically Symmetric ◽  
Short Hair ◽  
Anisotropic Matter ◽  
Symmetric Black Hole ◽  
Black Hole Solutions

We present spherically symmetric black hole solutions for Einstein gravity coupled to anisotropic matter. We show that these black holes have arbitrarily short hair, and argue for stability by showing that they can arise from dynamical collapse. We also show that a recent "no short hair" theorem does not apply to these solutions.

Universality of spectra of black holes

2014 ◽  
Vol 29 (36) ◽  
pp. 1450191 ◽  
Author(s):  
Xiao-Xiong Zeng ◽  
Qiang Li ◽  
Yi-Wen Han
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Area Spectrum ◽  
Spherically Symmetric ◽  
Action Variable ◽  
Intrinsic Properties ◽  
Entropy Spectrum ◽  
Symmetric Black Hole

Using exclusively an action variable, we quantize a static, spherically symmetric black hole. The spacings of the quantized entropy spectrum and area spectrum are found to be equal to the values given by Bekenstein. Interestingly, we find the spectra are independent of the hairs of the black holes and the mode of motion of a particle outside the spacetime, which depends only on the intrinsic properties of the gravity. Our result shows that the spectra are universal provided the spacetime owns a horizon.

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.

scholarly journals Global Embeddings of BTZ and Schwarzschild-ADS Type Black Holes in a Flat Space

Symmetry ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 841 ◽  
Author(s):  
Anton Sheykin ◽  
Dmitry Solovyev ◽  
Sergey Paston
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Cosmological Constant ◽  
Isometric Embedding ◽  
Flat Space ◽  
Ambient Space ◽  
Spherically Symmetric ◽  
Btz Black Hole ◽  
3 Dimensional ◽  
Negative Cosmological Constant

We study the problem of construction of global isometric embedding for spherically symmetric black holes with negative cosmological constant in various dimensions. Firstly, we show that there is no such embedding for 4D RN-AdS black hole in 6D flat ambient space, completing the classification which we started earlier. Then we construct an explicit embedding of non-spinning BTZ black hole in 6D flat ambient space. Using this embedding as an anzats, we then construct a global explicit embedding of d-dimensional Schwarzschild-AdS black hole in a flat ( d + 3 ) -dimensional ambient space.

Spherically symmetric black hole solution in mimetic gravity and anti-evaporation

2018 ◽  
Vol 15 (09) ◽  
pp. 1850154 ◽  
Author(s):  
G. G. L. Nashed
Keyword(s):  
Black Hole ◽  
Black Hole Solution ◽  
Spherically Symmetric ◽  
Mimetic Theory ◽  
Event Horizons ◽  
Flat Spacetime ◽  
Symmetric Black Hole ◽  
The Stability ◽  
Mimetic Gravity ◽  
Black Hole Solutions

In this paper, we study the mimetic theory and derive a new spherically symmetric black hole solution. The asymptotic behavior of this solution behaves as a flat spacetime. This black hole is characterized by the fact that it has different components of [Formula: see text] and [Formula: see text]. Nevertheless, both of these components have a coinciding Killing and event horizons. Furthermore, this black hole has curvature singularities which are stronger than those of the known black hole solutions in general relativity. This feature can be shown by calculating some invariants of curvature. We study the stability of the perturbation and the related anti-evaporation of the Nariai spacetime.

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