scholarly journals The Fundamental Roles of the de Sitter Vacuum

Universe ◽  
2020 ◽  
Vol 6 (8) ◽  
pp. 101 ◽  
Author(s):  
Irina Dymnikova
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Wide Class ◽  
Particle Physics ◽  
Black Hole Physics ◽  
Higgs Mechanism ◽  
Accelerated Expansion ◽  
De Sitter ◽  
Naked Singularities ◽  
De Sitter Vacuum

We overview the fundamental roles of the de Sitter vacuum in cosmology where it is responsible for powering the early inflationary stage(s) and the present accelerated expansion, in black hole physics where it provides the existence of a wide class of regular black holes and self-gravitating solitons replacing naked singularities, and in particle physics where it ensures the intrinsic relation of the Higgs mechanism with gravity and spacetime symmetry breaking.

scholarly journals Dynamics of Electromagnetic Fields and Structure of Regular Rotating Electrically Charged Black Holes and Solitons in Nonlinear Electrodynamics Minimally Coupled to Gravity

Universe ◽  
2019 ◽  
Vol 5 (10) ◽  
pp. 205 ◽  
Author(s):  
Irina Dymnikova ◽  
Evgeny Galaktionov
Keyword(s):  
Black Holes ◽  
Electromagnetic Fields ◽  
Nonlinear Electrodynamics ◽  
Axially Symmetric ◽  
De Sitter ◽  
Dynamical Equations ◽  
Naked Singularities ◽  
Charged Black Holes ◽  
De Sitter Vacuum ◽  
Electrically Charged

We study the dynamics of electromagnetic fields of regular rotating electrically charged black holes and solitons replacing naked singularities in nonlinear electrodynamics minimally coupled to gravity (NED-GR). They are related by electromagnetic and gravitational interactions and described by the axially symmetric NED-GR solutions asymptotically Kerr-Newman for a distant observer. Geometry is described by the metrics of the Kerr-Schild class specified by T t t = T r r ( p r = − ρ ) in the co-rotating frame. All regular axially symmetric solutions obtained from spherical solutions with the Newman-Janis algorithm belong to this class. The basic generic feature of all regular objects of this class, both electrically charged and electrically neutral, is the existence of two kinds of de Sitter vacuum interiors. We analyze the regular solutions to dynamical equations for electromagnetic fields and show which kind of a regular interior is favored by electromagnetic dynamics for NED-GR objects.

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 The fate of Schwarzschild–de Sitter black holes in f(R) gravity

2016 ◽  
Vol 31 (09) ◽  
pp. 1650054 ◽  
Author(s):  
Andrea Addazi ◽  
Salvatore Capozziello
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Thermal Radiation ◽  
Black Hole Physics ◽  
Black Hole Horizon ◽  
De Sitter ◽  
Trapped Surfaces ◽  
Emission Time ◽  
Marginally Trapped Surfaces

The semiclassical effects of anti-evaporating black holes can be discussed in the framework of f(R) gravity. In particular, the Bousso–Hawking–Nojiri–Odinstov anti-evaporation instability of degenerate Schwarzschild–de Sitter black holes (the so-called Nariai spacetime) leads to a dynamical increasing of black hole horizon in f(R) gravity. This phenomenon causes the following transition: emitting marginally trapped surfaces (TS) become space-like surfaces before the effective Bekenstein–Hawking emission time. As a consequence, Bousso–Hawking thermal radiation cannot be emitted in an anti-evaporating Nariai black hole. Possible implications in cosmology and black hole physics are also discussed.

scholarly journals Quantum information versus black hole physics: deep firewalls from narrow assumptions

2018 ◽  
Vol 376 (2123) ◽  
pp. 20170324 ◽  
Author(s):  
Samuel L. Braunstein ◽  
Stefano Pirandola
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Black Hole Physics ◽  
Foundations Of Quantum Mechanics ◽  
Contemporary Society ◽  
De Sitter ◽  
Original Surface ◽  
Thermodynamic Entropy ◽  
Initial Onset ◽  
Real Phenomenon

The prevalent view that evaporating black holes should simply be smaller black holes has been challenged by the firewall paradox. In particular, this paradox suggests that something different occurs once a black hole has evaporated to one-half its original surface area. Here, we derive variations of the firewall paradox by tracking the thermodynamic entropy within a black hole across its entire lifetime and extend it even to anti-de Sitter space–times. Our approach sweeps away many unnecessary assumptions, allowing us to demonstrate a paradox exists even after its initial onset (when conventional assumptions render earlier analyses invalid). The most natural resolution may be to accept firewalls as a real phenomenon. Further, the vast entropy accumulated implies a deep firewall that goes ‘all the way down’ in contrast with earlier work describing only a structure at the horizon. This article is part of a discussion meeting issue ‘Foundations of quantum mechanics and their impact on contemporary society’.

scholarly journals NON-STATIONARY ROTATING BLACK HOLES: ENTROPY AND HAWKING'S RADIATION

2005 ◽  
Vol 14 (08) ◽  
pp. 1373-1412 ◽  
Author(s):  
NG. IBOHAL ◽  
L. DORENDRO
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
The Body ◽  
Kerr Solution ◽  
De Sitter ◽  
Negative Mass ◽  
Radiation Process ◽  
Naked Singularities ◽  
Charged Black Holes ◽  
The Masses

In this paper we derive a class of non-stationary rotating solutions including Vaidya–Bonnor–de Sitter, Vaidya–Bonnor-monopole and Vaidya–Bonnor–Kerr. The rotating Viadya–Bonnor–de Sitter solution describes an embedded black hole that the rotating Vaidya–Bonnor black hole is embedded into the rotating de Sitter cosmological universe. In the case of the Vaidya–Bonnor–Kerr, the rotating Vaidya–Bonnor solution is embedded into the vacuum Kerr solution, and similarly, Vaidya–Bonnor-monopole. By considering the charge to be function of u and r, we discuss the Hawking's evaporation of the masses of variable-charged non-embedded, non-rotating and rotating Vaidya–Bonnor, and embedded rotating, Vaidya–Bonnor–de Sitter, Vaidya–Bonnor-monopole and Vaidya–Bonnor–Kerr, black holes. It is found that every electrical radiation of variable-charged black holes will produce a change in the mass of the body without affecting the Maxwell scalar in non-embedded cases; whereas in embedded cases, the Maxwell scalar, the cosmological constant, monopole charge and the Kerr mass are not affected by the radiation process. It was also found that during the Hawking's radiation process, after the complete evaporation of masses of these variable-charged black holes, the electrical radiation will continue creating (i) negative mass naked singularities in non-embedded ones, and (ii) embedded negative mass naked singularities in embedded black holes. The surface gravity, entropy and angular velocity of the horizon are presented for each of these non-stationary black holes.

scholarly journals Quantum Kerr(Newman) degenerate stringy vacua in 4D on a non-BPS brane

2014 ◽  
Vol 29 (29) ◽  
pp. 1450164 ◽  
Author(s):  
Sunita Singh ◽  
K. Priyabrat Pandey ◽  
Abhishek K. Singh ◽  
Supriya Kar
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Electric Charge ◽  
Low Energy ◽  
Quantum Geometry ◽  
De Sitter ◽  
Quantum Black Hole ◽  
Gravity Effects ◽  
Newman Black Hole ◽  
De Sitter Vacuum

We investigate some of the quantum gravity effects on a vacuum created pair of [Formula: see text]-brane by a nonlinear U(1) gauge theory on a D4-brane. In particular, we obtain a four-dimensional quantum Kerr–(Newman) black hole in an effective torsion curvature formalism sourced by a two form dynamics in the worldvolume of a D4-brane on S1. Interestingly, the event horizon is found to be independent of a nonlinear electric charge and the 4D quantum black hole is shown to describe degenerate vacua in string theory. We show that the quantum Kerr brane universe possesses its origin in a de Sitter vacuum. In a nearly S2-symmetric limit, the Kerr geometries may seen to describe a Schwarzschild and Reissner–Nordstrom quantum black holes. It is argued that a quantum Reissner–Nordstrom tunnels to a large class of degenerate Schwarzschild vacua. In a low energy limit, the nonlinear electric charge becomes significant at the expense of the degeneracies. In the limit, the quantum geometries may identify with the semiclassical black holes established in Einstein gravity. Analysis reveals that a quantum geometry on a vacuum created D3-brane universe may be described by a low energy perturbative string vacuum in presence of a nonperturbative quantum correction.

scholarly journals RECENT DEVELOPMENTS IN GRAVITATIONAL COLLAPSE AND SPACETIME SINGULARITIES

2011 ◽  
Vol 20 (14) ◽  
pp. 2641-2729 ◽  
Author(s):  
PANKAJ S. JOSHI ◽  
DANIELE MALAFARINA
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Gravitational Collapse ◽  
Spacetime Singularities ◽  
Black Hole Physics ◽  
Naked Singularity ◽  
Theory Of Relativity ◽  
Quantum Theories ◽  
Naked Singularities ◽  
Astrophysical Objects

It is now known that when a massive star collapses under the force of its own gravity, the final fate of such a continual gravitational collapse will be either a black hole or a naked singularity under a wide variety of physically reasonable circumstances within the framework of general theory of relativity. The research of recent years has provided considerable clarity and insight on stellar collapse, black holes and the nature and structure of spacetime singularities. We discuss several of these developments here. There are also important fundamental questions that remain unanswered on the final fate of collapse of a massive matter cloud in gravitation theory, especially on naked singularities which are hypothetical astrophysical objects and on the nature of cosmic censorship hypothesis. These issues have key implications for our understanding on black hole physics today, its astrophysical applications, and for certain basic questions in cosmology and possible quantum theories of gravity. We consider these issues here and summarize recent results and current progress in these directions. The emerging astrophysical and observational perspectives and implications are discussed, with particular reference to the properties of accretion disks around black holes and naked singularities, which may provide characteristic signatures and could help distinguish these objects.

scholarly journals Identification of a Regular Black Hole by Its Shadow

Universe ◽  
2019 ◽  
Vol 5 (7) ◽  
pp. 163 ◽  
Author(s):  
Irina Dymnikova ◽  
Kirill Kraav
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Kerr Black Hole ◽  
Axially Symmetric ◽  
De Sitter ◽  
Regular Solutions ◽  
Regular Black Hole ◽  
Rotating Black Holes ◽  
The Difference ◽  
De Sitter Vacuum

We study shadows of regular rotating black holes described by the axially symmetric solutions asymptotically Kerr for a distant observer, obtained from regular spherical solutions of the Kerr–Schild class specified by T t t = T r r ( p r = − ε ) . All regular solutions obtained with the Newman–Janis algorithm belong to this class. Their basic generic feature is the de Sitter vacuum interior. Information about the interior content of a regular rotating de Sitter-Kerr black hole can be in principle extracted from observation of its shadow. We present the general formulae for description of shadows for this class of regular black holes, and numerical analysis for two particular regular black hole solutions. We show that the shadow of a de Sitter-Kerr black hole is typically smaller than that for the Kerr black hole, and the difference depends essentially on the interior density and on the pace of its decreasing.

scholarly journals Driven black holes: from Kolmogorov scaling to turbulent wakes

2021 ◽  
Vol 2021 (7) ◽  
Author(s):  
Tomas Andrade ◽  
Christiana Pantelidou ◽  
Julian Sonner ◽  
Benjamin Withers
Keyword(s):  
Nonlinear Dynamics ◽  
Black Holes ◽  
General Relativity ◽  
Black Hole ◽  
Strong Field ◽  
De Sitter ◽  
Event Horizons ◽  
Binary Mergers ◽  
Tidal Deformations ◽  
Proof Of Principle

Abstract General relativity governs the nonlinear dynamics of spacetime, including black holes and their event horizons. We demonstrate that forced black hole horizons exhibit statistically steady turbulent spacetime dynamics consistent with Kolmogorov’s theory of 1941. As a proof of principle we focus on black holes in asymptotically anti-de Sitter spacetimes in a large number of dimensions, where greater analytic control is gained. We focus on cases where the effective horizon dynamics is restricted to 2+1 dimensions. We also demonstrate that tidal deformations of the horizon induce turbulent dynamics. When set in motion relative to the horizon a deformation develops a turbulent spacetime wake, indicating that turbulent spacetime dynamics may play a role in binary mergers and other strong-field phenomena.

scholarly journals Uptunneling to de Sitter

2020 ◽  
Vol 2020 (9) ◽  
Author(s):  
Mehrdad Mirbabayi
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
False Vacuum ◽  
De Sitter ◽  
Dimensional Theory ◽  
Hole Geometry ◽  
Horizon Geometry ◽  
Two Sides ◽  
Extremal Black Holes

Abstract We propose a Euclidean preparation of an asymptotically AdS2 spacetime that contains an inflating dS2 bubble. The setup can be embedded in a four dimensional theory with a Minkowski vacuum and a false vacuum. AdS2 approximates the near horizon geometry of a two-sided near-extremal Reissner-Nordström black hole, and the two sides can connect to the same Minkowski asymptotics to form a topologically nontrivial worm- hole geometry. Likewise, in the false vacuum the near-horizon geometry of near-extremal black holes is approximately dS2 times 2-sphere. We interpret the Euclidean solution as describing the decay of an excitation inside the wormhole to a false vacuum bubble. The result is an inflating region inside a non-traversable asymptotically Minkowski wormhole.

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