scholarly journals T-S-T Dual Black Hole

1997 ◽  
Vol 12 (12) ◽  
pp. 2293-2299
Author(s):  
Björn Andreas
Keyword(s):  
Black Hole ◽  
Space Time ◽  
Test String ◽  
White Hole ◽  
Duality Transformations ◽  
Black Hole Background

The sequence of intertwined T-S-T duality transformations acting on the 4D static uncharged black hole leads to a black hole background with horizon and singularity exchanged. It is shown that this space–time is extendible too. In particular we will see that a string moving into a black hole is dual to a string leaving a white hole. That offers the possibility that a test-string does not see the singularity.

scholarly journals SPACE–TIMES WITH INTEGRABLE SINGULARITY: BLACK–WHITE HOLES AND ASTROGENIC UNIVERSES

2013 ◽  
Vol 28 (02) ◽  
pp. 1350007 ◽  
Author(s):  
VLADIMIR N. LUKASH ◽  
VLADIMIR N. STROKOV
Keyword(s):  
Black Hole ◽  
Gravitational Field ◽  
Phenomenological Approach ◽  
Space Time ◽  
Schwarzschild Black Hole ◽  
White Hole ◽  
Black Hole Singularity

We use the phenomenological approach to study properties of space–time in the vicinity of the Schwarzschild black-hole singularity. Requiring finiteness of the Schwarzschild-like metrics we come to the notion of integrable singularity that is, in a sense, weaker than the conventional singularity and allows the (effective) matter to pass to the white-hole region. This leads to a possibility of generating a new universe there. Thanks to the gravitational field of the singularity, this universe is already born highly inflated ("singularity-induced inflation") before the ordinary inflation starts.

scholarly journals RADIATION OF THE INNER HORIZON OF THE REISSNER–NORDSTRÖM BLACK HOLE

2006 ◽  
Vol 15 (06) ◽  
pp. 817-843 ◽  
Author(s):  
ARI PELTOLA ◽  
JARMO MÄKELÄ
Keyword(s):  
Black Hole ◽  
Quantum Effects ◽  
Negative Energy ◽  
Space Time ◽  
Black Hole Thermodynamics ◽  
Positive Energy ◽  
Positive Temperature ◽  
White Hole ◽  
Virtual Particle ◽  
Inner Horizon

Despite over thirty years of research in black hole thermodynamics, our understanding of the possible role played by the inner horizons of Reissner–Nordström and Kerr–Newman black holes in black hole thermodynamics is still somewhat incomplete. There are derivations which imply that the temperature of the inner horizon is negative and it is not quite clear what this means. Motivated by this problem, we perform a detailed analysis of the radiation emitted by the inner horizon of the Reissner–Nordström black hole. As a result, we find that in a maximally extended Reissner–Nordström space–time virtual particle–antiparticle pairs are created at the inner horizon of the Reissner–Nordström black hole such that real particles with positive energy and temperature are emitted towards the singularity from the inner horizon and, as a consequence, antiparticles with negative energy are radiated away from the singularity through the inner horizon. We show that these antiparticles will be emitted from the white hole horizon in the maximally extended Reissner–Nordström space–time, at least when the hole is near extremality. The energy spectrum of the antiparticles leads to a positive temperature for the white hole horizon. In other words, our analysis predicts that in addition to the radition effects of black hole horizons, the white hole horizon also radiates. The black hole radiation is caused by the quantum effects at the outer horizon, whereas the white hole radiation is caused by the quantum effects at the inner horizon of the Reissner–Nordström black hole.

scholarly journals Loop Quantum Black Hole Extensions Within the Improved Dynamics

2021 ◽  
Vol 8 ◽  
Author(s):  
Rodolfo Gambini ◽  
Javier Olmedo ◽  
Jorge Pullin
Keyword(s):  
Black Hole ◽  
Quantum Gravity ◽  
Loop Quantum Gravity ◽  
Space Time ◽  
Anisotropic Fluid ◽  
Spherically Symmetric ◽  
Quantization Scheme ◽  
White Hole ◽  
Quantum Black Hole ◽  
Black Hole Singularity

We continue our investigation of an improved quantization scheme for spherically symmetric loop quantum gravity. We find that in the region where the black hole singularity appears in the classical theory, the quantum theory contains semi-classical states that approximate general relativity coupled to an effective anisotropic fluid. The singularity is eliminated and the space-time can be continued into a white hole space-time. This is similar to previously considered scenarios based on a loop quantum gravity quantization.

scholarly journals COLLAPSING AND STATIC THIN MASSIVE CHARGED DUST SHELLS IN A REISSNER–NORDSTRÖM BLACK HOLE BACKGROUND IN HIGHER DIMENSIONS

2008 ◽  
Vol 23 (19) ◽  
pp. 2943-2960 ◽  
Author(s):  
SIJIE GAO ◽  
JOSÉ P. S. LEMOS
Keyword(s):  
Black Hole ◽  
Thin Shell ◽  
Rest Mass ◽  
Higher Dimensions ◽  
Space Time ◽  
Particle Accelerators ◽  
Charged Dust ◽  
Empty Interior ◽  
Gravitational Radius ◽  
Black Hole Background

The problem of a spherically symmetric charged thin shell of dust collapsing gravitationally into a charged Reissner–Nordström black hole in d space–time dimensions is studied within the theory of general relativity. Static charged shells in such a background are also analyzed. First, a derivation of the equation of motion of such a shell in a d-dimensional space–time is given. Then, a proof of the cosmic censorship conjecture in a charged collapsing framework is presented, and a useful constraint which leads to an upper bound for the rest mass of a charged shell with an empty interior is derived. It is also proved that a shell with total mass equal to charge, i.e. an extremal shell, in an empty interior, can only stay in neutral equilibrium outside its gravitational radius. This implies that it is not possible to generate a regular extremal black hole by placing an extremal dust thin shell within its own gravitational radius. Moreover, it is shown, for an empty interior, that the rest mass of the shell is limited from above. Then, several types of behavior of oscillatory charged shells are studied. In the presence of a horizon, it is shown that an oscillatory shell always enters the horizon and reemerges in a new asymptotically flat region of the extended Reissner–Nordström space–time. On the other hand, for an overcharged interior, i.e. a shell with no horizons, an example showing that the shell can achieve a stable equilibrium position is presented. The results presented have applications in brane scenarios with extra large dimensions, where the creation of tiny higher-dimensional charged black holes in current particle accelerators might be a real possibility, and generalize to higher dimensions previous calculations on the dynamics of charged shells in four dimensions.

scholarly journals Black-Hole Models in Loop Quantum Gravity

Universe ◽  
2020 ◽  
Vol 6 (8) ◽  
pp. 125
Author(s):  
Martin Bojowald
Keyword(s):  
Black Hole ◽  
Quantum Gravity ◽  
Loop Quantum Gravity ◽  
Space Time ◽  
Classical Solutions ◽  
General Covariance ◽  
White Hole ◽  
Signature Change ◽  
Generalized Covariance ◽  
Line Elements

Dynamical black-hole scenarios have been developed in loop quantum gravity in various ways, combining results from mini and midisuperspace models. In the past, the underlying geometry of space-time has often been expressed in terms of line elements with metric components that differ from the classical solutions of general relativity, motivated by modified equations of motion and constraints. However, recent results have shown by explicit calculations that most of these constructions violate general covariance and slicing independence. The proposed line elements and black-hole models are therefore ruled out. The only known possibility to escape this sentence is to derive not only modified metric components but also a new space-time structure which is covariant in a generalized sense. Formally, such a derivation is made available by an analysis of the constraints of canonical gravity, which generate deformations of hypersurfaces in space-time, or generalized versions if the constraints are consistently modified. A generic consequence of consistent modifications in effective theories suggested by loop quantum gravity is signature change at high density. Signature change is an important ingredient in long-term models of black holes that aim to determine what might happen after a black hole has evaporated. Because this effect changes the causal structure of space-time, it has crucial implications for black-hole models that have been missed in several older constructions, for instance in models based on bouncing black-hole interiors. Such models are ruled out by signature change even if their underlying space-times are made consistent using generalized covariance. The causal nature of signature change brings in a new internal consistency condition, given by the requirement of deterministic behavior at low curvature. Even a causally disconnected interior transition, opening back up into the former exterior as some kind of astrophysical white hole, is then ruled out. New versions consistent with both generalized covariance and low-curvature determinism are introduced here, showing a remarkable similarity with models developed in other approaches, such as the final-state proposal or the no-transition principle obtained from the gauge-gravity correspondence.

scholarly journals Hawking evaporation cascade in the presence of backreaction effect

2017 ◽  
Vol 32 (16) ◽  
pp. 1750088 ◽  
Author(s):  
Avik Paul ◽  
Bibhas Ranjan Majhi
Keyword(s):  
Black Hole ◽  
Emission Spectrum ◽  
Event Horizon ◽  
Hawking Radiation ◽  
Space Time ◽  
Black Hole Mass ◽  
Planck Mass ◽  
Black Hole Background ◽  
Continuous Radiation ◽  
Physical Background

We study the cascade of Hawking emission spectrum from the event horizon in the presence of one loop backreaction effect in a black hole background. The space–time taken here is the modified Schwarzschild one. The analysis shows that it is possible to decrease the sparsity with the decrease in black hole mass. Moreover, at some particular value of mass, one has a continuous radiation cascade. This result is completely new and quite different from the usual one. An estimation of the mass for continuous one is also found. We see that the value is of the Planck mass order. In this process, it is observed that under a physical background, below a particular value of the mass, the Hawking radiation must stop and we have a remnant. This was absent in the earlier analysis.

scholarly journals LOGARITHMIC CORRECTION TO SCALING FOR MULTISPIN STRINGS IN THE AdS5 BLACK HOLE BACKGROUND

2008 ◽  
Vol 23 (05) ◽  
pp. 719-727
Author(s):  
A. L. LARSEN
Keyword(s):  
Black Hole ◽  
Radial Direction ◽  
Temperature Limit ◽  
Space Time ◽  
Explicit Solutions ◽  
Logarithmic Correction ◽  
High Temperature Limit ◽  
Black Hole Background ◽  
Correction To Scaling ◽  
The One

We find new explicit solutions describing closed strings spinning with equal angular momentum in two independent planes in the AdS5 black hole space–time. These are 2n-folded strings in the radial direction and also winding m times around an angular direction. We specially consider these solutions in the long string and high temperature limit, where it is shown that there is a logarithmic correction to the scaling between energy and spin. This is similar to the one-spin case. The strings are spinning, or actually orbiting around the black hole of the AdS5 black hole space–time, similar to the solutions previously found in black hole space–times.

Black-and-white hole as a space-time with integrable singularity

2016 ◽  
Vol 31 (02n03) ◽  
pp. 1641018 ◽  
Author(s):  
Vladimir N. Strokov ◽  
Vladimir N. Lukash ◽  
Elena V. Mikheeva
Keyword(s):  
General Relativity ◽  
Black Hole ◽  
Space Time ◽  
High Density ◽  
White Hole ◽  
Mathematical Procedure ◽  
Black And White ◽  
The Universe

We discuss the problem of singularities in general relativity and emphasize the distinction that should be made between what is understood to be mathematical and physical singularities. We revise examples of space-times that conventionally contain a singularity which, in a sense, does not manifest itself physically. A special attention is paid to the case of integrable singularities for which we propose a well-defined mathematical procedure used to extend the space-time beyond the singularity. We argue that this type of singularity may connect the interior of a black hole with a newly born universe (a space-time referred to as black-and-white hole) giving a resolution to the problem of initial high density and symmetry of the universe. We exemplify by presenting toy models of eternal and astrophysical black-and-white holes.

scholarly journals Black hole S-matrix for a scalar field

2021 ◽  
Vol 2021 (7) ◽  
Author(s):  
Panos Betzios ◽  
Nava Gaddam ◽  
Olga Papadoulaki
Keyword(s):  
Black Hole ◽  
Normal Modes ◽  
Massless Scalar ◽  
Scattering Process ◽  
Schwarzschild Black Hole ◽  
Asymptotically Flat ◽  
Scalar Particles ◽  
Black Hole Background ◽  
S Matrix ◽  
Do So

Abstract We describe a unitary scattering process, as observed from spatial infinity, of massless scalar particles on an asymptotically flat Schwarzschild black hole background. In order to do so, we split the problem in two different regimes governing the dynamics of the scattering process. The first describes the evolution of the modes in the region away from the horizon and can be analysed in terms of the effective Regge-Wheeler potential. In the near horizon region, where the Regge-Wheeler potential becomes insignificant, the WKB geometric optics approximation of Hawking’s is replaced by the near-horizon gravitational scattering matrix that captures non-perturbative soft graviton exchanges near the horizon. We perform an appropriate matching for the scattering solutions of these two dynamical problems and compute the resulting Bogoliubov relations, that combines both dynamics. This allows us to formulate an S-matrix for the scattering process that is manifestly unitary. We discuss the analogue of the (quasi)-normal modes in this setup and the emergence of gravitational echoes that follow an original burst of radiation as the excited black hole relaxes to equilibrium.

scholarly journals Normal-mode analysis for scalar fields in BTZ black-hole background

2009 ◽  
Vol 60 (2) ◽  
pp. 169-173 ◽  
Author(s):  
Sayan K. Chakrabarti ◽  
Pulak Ranjan Giri ◽  
Kumar S. Gupta
Keyword(s):  
Black Hole ◽  
Normal Mode ◽  
Normal Mode Analysis ◽  
Scalar Fields ◽  
Mode Analysis ◽  
Btz Black Hole ◽  
Black Hole Background
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