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 Bargmann–Wigner formulation and superradiance problem of bosons and fermions in Kerr space–time

2015 ◽  
Vol 30 (11) ◽  
pp. 1550052 ◽  
Author(s):  
Masakatsu Kenmoku ◽  
Y. M. Cho
Keyword(s):  
Negative Energy ◽  
Space Time ◽  
The Other ◽  
Positive Energy ◽  
Independent Components ◽  
Consistent Description ◽  
Other Hand ◽  
Kerr Space

The superradiance phenomena of massive bosons and fermions in the Kerr space–time are studied in the Bargmann–Wigner formulation. In case of bi-spinor, the four independent components spinors correspond to the four bosonic freedom: one scalar and three vectors uniquely. The consistent description of the Bargmann–Wigner equations between fermions and bosons shows that the superradiance of the type with positive energy (0 < ω) and negative momentum near horizon (p H < 0) is shown not to occur. On the other hand, the superradiance of the type with negative energy (ω < 0) and positive momentum near horizon (0 < p H ) is still possible for both scalar bosons and spinor fermions.

scholarly journals Varying Newton Constant and Black Hole to White Hole Quantum Tunneling

2020 ◽  
Author(s):  
Grigory Volovik
Keyword(s):  
Black Hole ◽  
Quantum Tunneling ◽  
Black Hole Thermodynamics ◽  
Black Hole Mass ◽  
Schwarzschild Black Hole ◽  
Dimensionless Quantity ◽  
White Hole ◽  
Thermodynamic Variable ◽  
Euclidean Action ◽  
Thermodynamics Of Black Holes

The thermodynamics of black holes is discussed for the case, when the Newton constant G is not a constant, but is the thermodynamic variable. This gives for the first law of the Schwarzschild black hole thermodynamics: d S BH = &minus; A d K + d M T BH , where the gravitational coupling K = 1 / 4 G , M is the black hole mass, A is the area of horizon, and T BH is Hawking temperature. From this first law it follows that the dimensionless quantity M 2 / K is the adiabatic invariant, which in principle can be quantized if to follow the Bekenstein conjecture. From the Euclidean action for the black hole it follows that K and A serve as dynamically conjugate variables. This allows us to calculate the quantum tunneling from the black hole to the white hole, and determine the temperature and entropy of the white hole.

scholarly journals Freely falling observer and black hole radiation

2014 ◽  
Vol 29 (11) ◽  
pp. 1450052 ◽  
Author(s):  
Wontae Kim ◽  
Edwin J. Son
Keyword(s):  
Black Hole ◽  
Energy Density ◽  
Event Horizon ◽  
Negative Energy ◽  
Positive Energy ◽  
Energy Curve ◽  
Zero Energy ◽  
Negative Energy Density ◽  
Black Hole Radiation

We find radiation in an infalling frame and present an explicit analytic evidence of the failure of no drama condition by showing that an infalling observer finds an infinite negative energy density at the event horizon. The negative and positive energy density regions are divided by the newly defined zero-energy curve (ZEC). The evaporating black hole is surrounded by the negative energy which can also be observed in the infalling frame.

Revisit on the thermodynamic stability of the noncommutative Schwarzschild black hole

2017 ◽  
Vol 26 (03) ◽  
pp. 1750018 ◽  
Author(s):  
Meng-Sen Ma ◽  
Yan-Song Liu ◽  
Huai-Fan Li
Keyword(s):  
Black Holes ◽  
Heat Capacity ◽  
Black Hole ◽  
Thermodynamic Stability ◽  
Black Hole Thermodynamics ◽  
Positive Temperature ◽  
Schwarzschild Black Hole ◽  
Horizon Thermodynamics ◽  
Thermodynamics Of Black Holes ◽  
Thermodynamic Curvature

In two frameworks, we discuss the thermodynamic stability of noncommutative geometry inspired Schwarzschild black hole (NCSBH). Under the horizon thermodynamics of black holes, we show that the NCSBH cannot be thermodynamically stable if requiring positive temperature. We note the inconsistency in the work of Larrañaga et al. and propose an effective first law of black hole thermodynamics for the NCSBH to eliminate the inconsistency. Based on the effective first law, we recalculate the heat capacity and the thermodynamic curvature by means of geometrothermodynamics (GTD) to revisit the thermodynamic stability.

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 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 Quantum simulation of particle pair creation near the event horizon

2020 ◽  
Vol 7 (9) ◽  
pp. 1476-1484
Author(s):  
Yao Wang ◽  
Chong Sheng ◽  
Yong-Heng Lu ◽  
Jun Gao ◽  
Yi-Jun Chang ◽  
...  
Keyword(s):  
General Relativity ◽  
Black Hole ◽  
Event Horizon ◽  
Single Photon ◽  
Quantum Effects ◽  
Gravitational Effect ◽  
Flat Space ◽  
Quantum Simulation ◽  
Quantum Evolution ◽  
Positive Energy

Abstract Though it is still a big challenge to unify general relativity and quantum mechanics in modern physics, the theory of quantum field related with the gravitational effect has been well developed and some striking phenomena are predicted, such as Hawking radiation. However, the direct measurement of these quantum effects under general relativity is far beyond present experiment techniques. Fortunately, the emulation of general relativity phenomena in the laboratory has become accessible in recent years. However, up to now, these simulations are limited either in classical regime or in flat space whereas quantum simulation related with general relativity is rarely involved. Here we propose and experimentally demonstrate a quantum evolution of fermions in close proximity to an artificial black hole on a photonic chip. We successfully observe the acceleration behavior, quantum creation, and evolution of a fermion pair near the event horizon: a single-photon wave packet with positive energy escapes from the black hole while negative energy is captured. Our extensible platform not only provides a route to access quantum effects related with general relativity, but also has the potentiality to investigate quantum gravity in future.

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.

ABSORPTION OF A PARTICLE BY A ROTATING BLACK HOLE

2012 ◽  
Vol 27 (27) ◽  
pp. 1250155 ◽  
Author(s):  
LEON HELLER
Keyword(s):  
Black Hole ◽  
Angular Momentum ◽  
Test Particle ◽  
Kerr Black Hole ◽  
Negative Energy ◽  
Positive Energy ◽  
Energy Particle ◽  
Rotating Black Hole ◽  
Particle Approximation

We examine the absorption of a test particle by a near-extreme Kerr black hole, including both positive and negative energy particles. Allowing arbitrary values of the particle's radial momentum at the horizon, we display the region in which the absorption of the particle would "overspin" the black hole and also the region in which it would reduce the area of the black hole. The portions of these regions for a positive energy particle, shrink and disappear as the angular momentum of the initial black hole approaches the extreme Kerr limit. But even in that limit the absorption of a negative energy particle can reduce the area. Proposals to go beyond the test particle approximation are also discussed.

scholarly journals Varying Newton Constant and Black Hole to White Hole Quantum Tunneling

Universe ◽  
2020 ◽  
Vol 6 (9) ◽  
pp. 133
Author(s):  
Grigory Volovik
Keyword(s):  
Black Hole ◽  
Quantum Tunneling ◽  
Condensed Matter ◽  
Black Hole Thermodynamics ◽  
Black Hole Mass ◽  
Schwarzschild Black Hole ◽  
Dimensionless Quantity ◽  
White Hole ◽  
Euclidean Action ◽  
Thermodynamics Of Black Holes

The thermodynamics of black holes is discussed for the case, when the Newton constant G is not a constant, but it is the thermodynamic variable. This gives for the first law of the Schwarzschild black hole thermodynamics: dSBH=−AdK+dMTBH, where the gravitational coupling K=1/4G, M is the black hole mass, A is the area of horizon, and TBH is Hawking temperature. From this first law, it follows that the dimensionless quantity M2/K is the adiabatic invariant, which, in principle, can be quantized if to follow the Bekenstein conjecture. From the Euclidean action for the black hole it follows that K and A serve as dynamically conjugate variables. Using the Painleve–Gullstrand metric, which in condensed matter is known as acoustic metric, we calculate the quantum tunneling from the black hole to the white hole. The obtained tunneling exponent suggests that the temperature and entropy of the white hole are negative.

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