Asymptotically flat black hole solutions in quadratic gravity

2021 ◽  
pp. 2142015
Author(s):  
Frank Saueressig ◽  
Mina Galis ◽  
Jesse Daas ◽  
Amir Khosravi
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Field Equations ◽  
Schwarzschild Solution ◽  
Asymptotically Flat ◽  
Singularity Theorems ◽  
Dead End ◽  
Quadratic Gravity ◽  
Symmetric Black Hole ◽  
Black Hole Solutions

Black holes constitute some of the most fascinating objects in our universe. According to Einstein’s theory of general relativity, they are also deceivingly simple: Schwarzschild black holes are completely determined by their mass. Moreover, the singularity theorems by Penrose and Hawking indicate that they host a curvature singularity within their event horizon. The presence of the latter invites the question whether these dead-end points of spacetime can be made regular by considering (quantum) corrections to the classical field equations. In this light, we use the Frobenius method to investigate the phase space of asymptotically flat, static, and spherically symmetric black hole solutions in quadratic gravity. We argue that the only asymptotically flat black hole solution visible in this approach is the Schwarzschild solution.

scholarly journals Thermodynamics and reentrant phase transition for logarithmic nonlinear charged black holes in massive gravity

2020 ◽  
Vol 29 (12) ◽  
pp. 2050081
Author(s):  
S. Rajaee Chaloshtary ◽  
M. Kord Zangeneh ◽  
S. Hajkhalili ◽  
A. Sheykhi ◽  
S. M. Zebarjad
Keyword(s):  
Phase Transition ◽  
Black Holes ◽  
Black Hole ◽  
Quantum Effect ◽  
Massive Gravity ◽  
Nonlinear Electrodynamics ◽  
Model Parameters ◽  
Thermodynamic Quantities ◽  
Field Equations ◽  
Black Hole Solutions

We investigate a new class of [Formula: see text]-dimensional topological black hole solutions in the context of massive gravity and in the presence of logarithmic nonlinear electrodynamics. Exploring higher-dimensional solutions in massive gravity coupled to nonlinear electrodynamics is motivated by holographic hypothesis as well as string theory. We first construct exact solutions of the field equations and then explore the behavior of the metric functions for different values of the model parameters. We observe that our black holes admit the multi-horizons caused by a quantum effect called anti-evaporation. Next, by calculating the conserved and thermodynamic quantities, we obtain a generalized Smarr formula. We find that the first law of black holes thermodynamics is satisfied on the black hole horizon. We study thermal stability of the obtained solutions in both canonical and grand canonical ensembles. We reveal that depending on the model parameters, our solutions exhibit a rich variety of phase structures. Finally, we explore, for the first time without extending thermodynamics phase space, the critical behavior and reentrant phase transition for black hole solutions in massive gravity theory. We realize that there is a zeroth-order phase transition for a specified range of charge value and the system experiences a large/small/large reentrant phase transition due to the presence of nonlinear electrodynamics.

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.

QUANTUM ERGOSPHERE AND HAWKING PROCESS

1999 ◽  
Vol 14 (28) ◽  
pp. 1951-1960 ◽  
Author(s):  
ZHONG-HENG LI
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Thermal Radiation ◽  
Radiation Spectrum ◽  
Spherically Symmetric ◽  
Field Equations ◽  
Stationary Black Hole ◽  
Symmetric Black Hole ◽  
Hawking Process ◽  
Nonstationary Black Hole

We study both spherically symmetric and rotating (Kerr) nonstationary black holes and discuss the radiation of these black holes via the Hawking process. We find that the thermal radiation spectrum of a nonstationary black hole is obviously dependent on the spin state of a particle and is different from the case of a stationary black hole. This effect originates from the quantum ergosphere. We also find that the field equations of spin s=0,1/2,1 and 2 can combine into a generalized Teukolsky-type master equation with sources for any spherically symmetric black hole.

scholarly journals NONEXTREME BLACK HOLES FROM INTERSECTING M-BRANES

1998 ◽  
Vol 13 (08) ◽  
pp. 1305-1328 ◽  
Author(s):  
NOBUYOSHI OHTA ◽  
TAKASHI SHIMIZU
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Higher Dimensions ◽  
Symmetric Case ◽  
Spherically Symmetric ◽  
Field Equations ◽  
Deformation Parameters ◽  
Special Cases ◽  
Two Parameter ◽  
Black Hole Solutions

We investigate the possibility of extending nonextreme black hole solutions made of intersecting M-branes to those with two nonextreme deformation parameters, similar to Reissner–Nordstrøm solutions. General analysis of possible solutions is carried out to reduce the problem of solving field equations to a simple algebraic one for static spherically-symmetric case in D dimensions. The results are used to show that the extension to two-parameter solutions is possible for D= 4,5 dimensions but not for higher dimensions, and that the area of horizon always vanishes in the extreme limit for black hole solutions for D≥6 except for two very special cases which are identified. Various solutions are also summarized.

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 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 MULTI-BLACK HOLES AND INSTANTONS IN EFFECTIVE STRING THEORY

1998 ◽  
Vol 07 (01) ◽  
pp. 73-80
Author(s):  
S. DEMELIO ◽  
S. MIGNEMI
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
String Theory ◽  
Higher Dimensions ◽  
Field Equations ◽  
Charged Black Holes ◽  
Effective String Theory ◽  
Black Hole Solutions

The effective four-dimensional action for string theory contains non-minimal couplings of the dilaton and the moduli arising from the compactification of higher dimensions. We show that the resulting field equations admit multi-black hole solutions. The Euclidean continuation of these solutions can be interpreted as an instanton mediating the splitting and recombination of the throat of extremal magnetically charged black holes.

scholarly journals Charged and Non-Charged Black Hole Solutions in Mimetic Gravitational Theory

Symmetry ◽  
2018 ◽  
Vol 10 (11) ◽  
pp. 559 ◽  
Author(s):  
Gamal Nashed
Keyword(s):  
Black Holes ◽  
General Relativity ◽  
Black Hole ◽  
Gravitational Theory ◽  
Relativity Theory ◽  
Charged Black Hole ◽  
Field Equations ◽  
General Relativity Theory ◽  
Mimetic Theory ◽  
Black Hole Solutions

In this study, we derive, in the framework of mimetic theory, charged and non-charged black hole solutions for spherically symmetric as well as flat horizon spacetimes. The asymptotic behavior of those black holes behave as flat or (A)dS spacetimes and coincide with the solutions derived before in general relativity theory. Using the field equations of non-linear electrodynamics mimetic theory we derive new black hole solutions with monopole and quadrupole terms. The quadruple term of those black holes is related by a constant so that its vanishing makes the solutions coincide with the linear Maxwell black holes. We study the singularities of those solutions and show that they possess stronger singularity than the ones known in general relativity. Among many things, we study the horizons as well as the heat capacity to see if the black holes derived in this study have thermodynamical stability or not.

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.

New black hole solutions of Einstein field equations and their Riemann curvature tensors

2015 ◽  
Vol 30 (06) ◽  
pp. 1550028 ◽  
Author(s):  
Farhad Ali
Keyword(s):  
Black Hole ◽  
Riemann Curvature ◽  
Einstein Field Equations ◽  
Field Equations ◽  
Cylindrically Symmetric ◽  
Symmetric Black Hole ◽  
Curvature Tensors ◽  
Black Hole Solutions

Here, we are going to discuss some new cases of cylindrically symmetric black hole solutions of Einstein field equations (EFEs). These are new solutions which we have not seen in the literature. We also listed their Riemann curvature tensors.

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