scholarly journals THE SPHERICAL SYMMETRY BLACK HOLE COLLAPSE IN EXPANDING UNIVERSE

2012 ◽  
Vol 21 (04) ◽  
pp. 1250039 ◽  
Author(s):  
J. T. FIROUZJAEE
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Cosmological Constant ◽  
Spherical Symmetry ◽  
Tube Surface ◽  
Expanding Universe ◽  
Surface Behavior ◽  
Singularity Line ◽  
Cosmological Black Holes

The spherical symmetry black holes are considered in expanding background. The singularity line and the marginally trapped tube surface behavior are discussed. In particular, we address the conditions whether dynamical horizon forms for these cosmological black holes. We also discuss about the cosmological constant effect on these black hole and the redshift of the light which comes from the marginally trapped tube surface.

scholarly journals Extremal Cosmological Black Holes in Horndeski Gravity and the Anti-Evaporation Regime

Universe ◽  
2020 ◽  
Vol 6 (11) ◽  
pp. 210
Author(s):  
Ismael Ayuso ◽  
Diego Sáez-Chillón Gómez
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Cosmological Constant ◽  
Linear Order ◽  
Scalar Tensor Theory ◽  
De Sitter ◽  
Tensor Theory ◽  
Effective Cosmological Constant ◽  
Cosmological Black Holes ◽  
Extremal Black Holes

Extremal cosmological black holes are analysed in the framework of the most general second order scalar-tensor theory, the so-called Horndeski gravity. Such extremal black holes are a particular case of Schwarzschild-De Sitter black holes that arises when the black hole horizon and the cosmological one coincide. Such metric is induced by a particular value of the effective cosmological constant and is known as Nariai spacetime. The existence of this type of solutions is studied when considering the Horndeski Lagrangian and its stability is analysed, where the so-called anti-evaporation regime is studied. Contrary to other frameworks, the radius of the horizon remains stable for some cases of the Horndeski Lagrangian when considering perturbations at linear order.

scholarly journals Central charges for AdS black holes

2021 ◽  
Author(s):  
Malcolm Perry ◽  
Maria J Rodriguez
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Cosmological Constant ◽  
Central Charge ◽  
Negative Cosmological Constant ◽  
Ads Black Holes ◽  
Kerr Black Holes ◽  
Distinguishing Features ◽  
Area Law ◽  
Cardy Formula

Abstract Nontrivial diffeomorphisms act on the horizon of a generic 4D black holes and create distinguishing features referred to as soft hair. Amongst these are a left-right pair of Virasoro algebras with associated charges that reproduce the Bekenstein-Hawking entropy for Kerr black holes. In this paper we show that if one adds a negative cosmological constant, there is a similar set of infinitesimal diffeomorphisms that act non-trivially on the horizon. The algebra of these diffeomorphisms gives rise to a central charge. Adding a boundary counterterm, justified to achieve integrability, leads to well-defined central charges with cL = cR. The macroscopic area law for Kerr-AdS black holes follows from the assumption of a Cardy formula governing the black hole microstates.

scholarly journals HORIZONS IN MATTER: BLACK HOLE HAIR VERSUS NULL BIG BANG

2009 ◽  
Vol 18 (14) ◽  
pp. 2283-2287 ◽  
Author(s):  
K. A. BRONNIKOV ◽  
OLEG B. ZASLAVSKII
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Cosmological Constant ◽  
Cosmic Strings ◽  
Density Ratio ◽  
Radial Pressure ◽  
Big Bang ◽  
Spherically Symmetric ◽  
Normal Matter ◽  
Phantom Matter

It is shown that only particular kinds of matter (in terms of the "radial" pressure-to-density ratio w) can coexist with Killing horizons in black hole or cosmological space–times. Thus, for arbitrary (not necessarily spherically symmetric) static black holes, admissible are vacuum matter (w = −1, i.e. the cosmological constant or its generalization with the same value of w) and matter with certain values of w between 0 and −1, in particular a gas of disordered cosmic strings (w = −1/3). If the cosmological evolution starts from a horizon (the so-called null big bang scenarios), this horizon can coexist with vacuum matter and certain kinds of phantom matter with w ≤ −3. It is concluded that normal matter in such scenarios is entirely created from vacuum.

scholarly journals Light from Reissner–Nordstrom–de Sitter black holes

2021 ◽  
pp. 2150162
Author(s):  
Ion I. Cotăescu
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Expanding Universe ◽  
De Sitter ◽  
Principal Parameter ◽  
Null Geodesics ◽  
Charged Black Holes ◽  
Peculiar Velocities ◽  
First Time

We derive for the first time the form of the spiral null geodesics around the photon sphere of the Reissner–Nordstrom black hole in the de Sitter expanding universe. Moreover, we obtain the principal parameter we need for deriving, according to our method [I. I. Cotăescu, Eur. Phys. J. C 81, 32 (2021)], the black hole shadow and the related redshift as measured by a remote observer situated in the asymptotic zone. We obtain thus a criterion of detecting charged black holes without peculiar velocities when one knows the mass, redshift and the black hole shadow.

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.

scholarly journals Critical Phenomena of Charged AdS Black Holes in Rastall Gravity

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
De-Cheng Zou ◽  
Ming Zhang ◽  
Chao Wu ◽  
Rui-Hong Yue
Keyword(s):  
Phase Transition ◽  
Black Holes ◽  
Black Hole ◽  
Phase Transitions ◽  
Cosmological Constant ◽  
De Sitter ◽  
Perfect Fluids ◽  
Large Black Hole ◽  
Ads Black Holes ◽  
Phantom Fields

We construct analytical charged anti-de Sitter (AdS) black holes surrounded by perfect fluids in four dimensional Rastall gravity. Then, we discuss the thermodynamics and phase transitions of charged AdS black holes immersed in regular matter like dust and radiation, or exotic matter like quintessence, ΛCDM type, and phantom fields. Surrounded by phantom field, the charged AdS black hole demonstrates a new phenomenon of reentrant phase transition (RPT) when the parameters Q, Np, and ψ satisfy some certain condition, along with the usual small/large black hole (SBH/LBH) phase transition for the surrounding dust, radiation, quintessence, and cosmological constant fields.

Cosmological constant effect on charged and rotating black hole shadows

2021 ◽  
pp. 2150188
Author(s):  
A. Belhaj ◽  
M. Benali ◽  
A. El Balali ◽  
W. El Hadri ◽  
H. El Moumni
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Cosmological Constant ◽  
Moduli Space ◽  
Emission Rate ◽  
De Sitter ◽  
Naked Singularities ◽  
Rotating Black Holes ◽  
Rotation Parameters ◽  
Made In

Motivated by recent astrophysical observations, we investigate the shadow behaviors of four-dimensional charged rotating black holes with a cosmological constant. This study is made in terms of a reduced moduli space parameterized by the charge and the rotation parameters. For fixed observers, we analyse in some details the shadow behaviors and the corresponding naked singularities of Kerr–Newman and Kerr–Sen four-dimensional black holes in Anti-de Sitter backgrounds. Then, a comparative discussion is provided by computing the geometrical observables and the energy emission rate.

scholarly journals Thermodynamic Volume in AdS/CFT

2018 ◽  
Vol 168 ◽  
pp. 07003
Author(s):  
Kyung Kiu Kim ◽  
Byoungjoon Ahn
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Cosmological Constant ◽  
Chemical Potential ◽  
Entanglement Entropy ◽  
Extended Thermodynamics ◽  
Ads Black Holes

In this note, we study on extended thermodynamics of AdS black holes by varying cosmological constant. We found and discussed pressure and volume of both bulk and boundary physics through AdS/CFT correspondence. In particular, we derive the relation between thermodynamic volume and a chemical potential for M2 brane dual to four dimensional AdS space. In addition, we show that thermodynamic volume of hyperbolic black hole is related to ‘entanglement pressure’ coming from a generalized first law of entanglement entropy.

scholarly journals De sitter magnetic black hole dipole with a supersymmetric horizon

2021 ◽  
Vol 2021 (12) ◽  
Author(s):  
Davide Astesiano ◽  
S.L. Cacciatori
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Scalar Field ◽  
Cosmological Constant ◽  
The Other ◽  
Gauge Fields ◽  
Positive Pressure ◽  
Closed Universe ◽  
De Sitter ◽  
Extremal Black Holes

Abstract We find a new non BPS solution in N = 2 D = 4 gauged supergravity coupled to U(1) gauge fields and matter. It consists in a closed universe with two extremal black holes of equal size, surrounding two singularities. They have opposite magnetic charges (and no electric charges), but stay in static equilibrium thanks to the positive pressure of a cosmological constant. The geometry is perfectly symmetric under the exchange of the black holes and the flip of the sign of the charges. However the scalar field is non constant and non symmetric, with different values at the horizons, which depend on a real modulus. Remarkably we show that it satisfies the attractor mechanism and the entropy indeed depends only on the magnetic charges. At one of the horizons the solution becomes $$ \frac{1}{2} $$ 1 2 -BPS supersymmetric, while at the other one there is no supersymmetry, but the entropy remains independent from the scalar modulus.

scholarly journals NONSINGULAR BLACK HOLES FROM GRAVITY–MATTER-BRANE LAGRANGIANS

2010 ◽  
Vol 25 (08) ◽  
pp. 1571-1596 ◽  
Author(s):  
EDUARDO GUENDELMAN ◽  
ALEXANDER KAGANOVICH ◽  
EMIL NISSIMOV ◽  
SVETLANA PACHEVA
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Cosmological Constant ◽  
Radial Coordinate ◽  
De Sitter ◽  
Wormhole Solution ◽  
Interior Region ◽  
Exterior Region ◽  
Inner Horizon ◽  
Self Consistent

We consider self-consistent coupling of bulk Einstein–Maxwell–Kalb–Ramond system to codimension-one charged lightlikep-brane with dynamical (variable) tension (LL-brane). The latter is described by a manifestly reparametrization-invariant worldvolume action significantly different from the ordinary Nambu–Goto one. We show that the LL-brane is the appropriate gravitational and charge source in the Einstein–Maxwell–Kalb–Ramond equations of motion needed to generate a self-consistent solution describing nonsingular black hole. The latter consists of de Sitter interior region and exterior Reissner–Nordström region glued together along their common horizon (it is the inner horizon from the Reissner–Nordström side). The matching horizon is automatically occupied by the LL-brane as a result of its worldvolume Lagrangian dynamics, which dynamically generates the cosmological constant in the interior region and uniquely determines the mass and charge parameters of the exterior region. Using similar techniques we construct a self-consistent wormhole solution of Einstein–Maxwell system coupled to electrically neutral LL-brane, which describes two identical copies of a nonsingular black hole region being the exterior Reissner–Nordström region above the inner horizon, glued together along their common horizon (the inner Reissner–Nordström one) occupied by the LL-brane. The corresponding mass and charge parameters of the two black hole "universes" are explicitly determined by the dynamical LL-brane tension. This also provides an explicit example of Misner–Wheeler "charge without charge" phenomenon. Finally, this wormhole solution connecting two nonsingular black holes can be transformed into a special case of Kantowski–Sachs bouncing cosmology solution if instead of Reissner–Nordström we glue together two copies of the exterior Reissner–Nordström–de Sitter region with big enough bare cosmological constant, such that the radial coordinate becomes a timelike variable everywhere in the two "universes," except at the matching hypersurface occupied by the LL-brane.

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