scholarly journals REAL TUNNELING AND BLACK HOLE CREATION

1998 ◽  
Vol 07 (01) ◽  
pp. 111-127 ◽  
Author(s):  
ZHONG CHAO WU
Keyword(s):  
Black Hole ◽  
De Sitter ◽  
Planck Constant ◽  
Gravitational Instanton ◽  
Constrained Gravitational Instanton ◽  
Black Hole Spacetime ◽  
Sitter Background ◽  
Transition Surface ◽  
The Universe ◽  
Black Hole Creation

We discuss the Hawking theory of quantum cosmology with regard to approximation at the lowest order of the Planck constant. At this level, the quantum scenario will be reduced to its classical evolutions in real and imaginary times. We restrict our attention to the so-called real tunneling case. It can be shown that, even at this level, there still exist some quantum effects, the classical field equation may not hold at the transition surface. One can introduce the concept of constrained gravitational instanton. It may play some important role in the scenario of black hole creation in the inflationary background at the Planckian era of the universe. From the constrained gravitational instanton, the real tunneling can occur through different ways. Consequently, it will lead to the creation of different parts of the black hole spacetime in the de Sitter background. The global aspects of the black hole creation are discussed.

scholarly journals QUANTUM FIELDS IN SCHWARZSCHILD–DE SITTER SPACE

1998 ◽  
Vol 07 (06) ◽  
pp. 887-907 ◽  
Author(s):  
ZHONG CHAO WU
Keyword(s):  
Black Hole ◽  
Mass Parameter ◽  
Primordial Black Hole ◽  
De Sitter ◽  
Gravitational Instanton ◽  
Boundary State ◽  
Spinor Fields ◽  
Black Hole Background ◽  
Constrained Gravitational Instanton ◽  
Sitter Background

In the No-Boundary Universe a primordial black hole is created from a constrained gravitational instanton. The black hole created is immersed in the de Sitter background with a positive cosmological constant. The constrained instanton is characterized not only by the external parameters, the mass parameter, charge and angular momentum, but also by one more internal parameter, the identification period in the imaginary time coordinate. Although the period has no effect on the black hole background, its inverse is the temperature of the no-boundary state of the perturbation modes perceived by an observer. By using the Bogoliubov transformation, we show that the perturbation modes of both scalar and spinor fields are in thermal equilibrium with the black hole background at the arbitrary temperature. However, for the two extreme cases, the de Sitter and the Nariai models, the no-boundary state remains pure.

scholarly journals Quantum Creation of a Black Hole

1997 ◽  
Vol 06 (02) ◽  
pp. 199-210 ◽  
Author(s):  
Zhong Chao Wu
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Wave Function ◽  
De Sitter Space ◽  
Total Entropy ◽  
De Sitter ◽  
Conical Singularities ◽  
Gravitational Instanton ◽  
The Universe ◽  
Black Hole Creation

Using the Hartle–Hawking no-boundary proposal for the wave function of the universe, we can study the wave function and probability of a single black hole created at the birth of the universe. The black hole originates from a generalized gravitational instanton with conical singularities. The wave function and probability of a universe with a black hole are calculated at the W K B level. The probability of a black hole creation is the exponential of one quarter of the sum of areas of the black hole and cosmological horizons. One quarter of this sum is the total entropy of universe. We show that these arguments apply to all kinds of black holes in the de Sitter space background.

scholarly journals QUANTUM CREATION OF A TOPOLOGICAL BLACK HOLE

2000 ◽  
Vol 15 (25) ◽  
pp. 1589-1595 ◽  
Author(s):  
ZHONG CHAO WU
Keyword(s):  
Phase Transition ◽  
Black Hole ◽  
De Sitter ◽  
Sitter Background ◽  
The Difference ◽  
The Universe

The constrained instanton method is used to study quantum creation of a vacuum or charged topological black hole. At the WKB level, the relative creation probability is the exponential of a quarter of the sum of the horizon areas associated with the seed instanton. The universe without a black hole has the highest creation probability. The difference between this creation scenario and the Hawking–Page phase transition in the anti-de Sitter background is clarified.

scholarly journals PRIMORDIAL BLACK HOLE FORMATION FROM INFLATON

2000 ◽  
Vol 09 (06) ◽  
pp. 705-710 ◽  
Author(s):  
XIN HE MENG ◽  
BIN WANG ◽  
S. FENG
Keyword(s):  
Black Hole ◽  
Primordial Black Hole ◽  
Primordial Black Holes ◽  
De Sitter ◽  
Hole Formation ◽  
Black Hole Formation ◽  
Expansion Of The Universe ◽  
Slow Rolling ◽  
The Relationship ◽  
The Universe

Measurements of the distances to SNe Ia have produced strong evidence that the expansion of the Universe is really accelarating, implying the existence of a nearly uniform component of dark energy with the simplest explanation as a cosmological constant. In this paper a small changing cosmological term is proposed, which is a function of a slow-rolling scalar field, by which the de Sitter primordial black holes' properties, for both charged and uncharged cases, are carefully examined and the relationship between the black hole formation and the energy transfer of the inflaton is eluciated. The criterion for primordial black hole formation is given.

scholarly journals Non-Singular Model of Magnetized Black Hole Based on Nonlinear Electrodynamics

Universe ◽  
2019 ◽  
Vol 5 (12) ◽  
pp. 225 ◽  
Author(s):  
Sergey I. Kruglov
Keyword(s):  
Black Holes ◽  
Heat Capacity ◽  
Black Hole ◽  
Hawking Temperature ◽  
Nonlinear Electrodynamics ◽  
De Sitter ◽  
Fundamental Length ◽  
Gravity Effects ◽  
Black Hole Spacetime ◽  
Thermodynamics Of Black Holes

A new modified Hayward metric of magnetically charged non-singular black hole spacetime in the framework of nonlinear electrodynamics is constructed. When the fundamental length introduced, characterising quantum gravity effects, vanishes, one comes to the general relativity coupled with the Bronnikov model of nonlinear electrodynamics. The metric can have one (an extreme) horizon, two horizons of black holes, or no horizons corresponding to the particle-like solution. Corrections to the Reissner–Nordström solution are found as the radius approaches infinity. As r → 0 the metric has a de Sitter core showing the absence of singularities, the asymptotic of the Ricci and Kretschmann scalars are obtained and they are finite everywhere. The thermodynamics of black holes, by calculating the Hawking temperature and the heat capacity, is studied. It is demonstrated that phase transitions take place when the Hawking temperature possesses the maximum. Black holes are thermodynamically stable at some range of parameters.

BLACK HOLE QUANTIZATION, THERMODYNAMICS AND COSMOLOGICAL CONSTANT

2004 ◽  
Vol 13 (05) ◽  
pp. 885-898
Author(s):  
LI XIANG
Keyword(s):  
Black Hole ◽  
Cosmological Constant ◽  
Vacuum Energy ◽  
Planck Scale ◽  
Additional Term ◽  
Logarithmic Correction ◽  
De Sitter ◽  
Horizon Area ◽  
Constant Distance ◽  
The Universe

Bekenstein argues that the horizon area of a black hole has a constant distance spectrum. We investigate the effects of such a discrete spectrum on the thermodynamics of a Schwarzchild black hole (SBH) and a Schwarzchild–de Sitter black hole (SdBH), in terms of the time-energy uncertainty relation and Stefan–Boltzman law. For the massive SBH, a negative and logarithmic correction to the Bekenstein–Hawking entropy is obtained, as well as other authors by using other methods. As to the minimal hole near the Planck scale, its entropy is no longer proportional to the horizon area, but is of order of the mass of the hole. This is similar to an excited stringy state. The vanishing heat capacity of such a minimal black hole implies that it may be a remnant as the ground state of the evaporating hole. The properties of a SdBH are similar to the SBH, except for an additional term of square area associated with the cosmological constant. In order to maintain the validity of the Bekenstein–Hawking formula, the cosmological constant is strongly limited by the size of the biggest black hole in the universe. A relation associated with the cosmological constant, Planck area and the Stefan–Boltzman constant is obtained. The cosmological constant is not only related to the vacuum energy, but is also related to the thermodynamics.

scholarly journals ORIGIN OF MATTER OUT OF PURE CURVATURE

2008 ◽  
Vol 17 (03n04) ◽  
pp. 513-518 ◽  
Author(s):  
NARESH DADHICH ◽  
HIDEKI MAEDA
Keyword(s):  
Black Hole ◽  
Black Hole Solution ◽  
Space Time ◽  
De Sitter ◽  
Matter Distribution ◽  
Static Black Hole ◽  
Negative Constant ◽  
Usual Formula ◽  
The Universe ◽  
Kaluza Klein

We propose a mechanism for the origin of matter in the universe in the framework of Einstein–Gauss–Bonnet gravity in higher dimensions. The new static black hole solution recently discovered by the authors,1 with the Kaluza–Klein split of space–time as a product of the usual [Formula: see text] with a space of negative constant curvature, is indeed a pure gravitational creation of a black hole which is also endowed with a Maxwell-like gravitational charge in four-dimensional vacuum space–time. This solution has been further generalized to include radially flowing radiation, which means that extra-dimensional curvature also produces matter distribution asymptotically, resembling charged null dust. The static black hole could thus be envisioned as being formed from anti–de Sitter space–time by the collapse of radially inflowing charged null dust. It thus establishes the remarkable reciprocity between matter and gravity — as matter produces gravity (curvature), gravity produces matter. After the Kaluza–Klein generation of the Maxwell field, this is the first instance of realization of matter without matter in the classical framework.

scholarly journals NONSTATIC CHARGED BTZ-LIKE BLACK HOLES IN N+1 DIMENSIONS

2012 ◽  
Vol 21 (03) ◽  
pp. 1250022 ◽  
Author(s):  
SUSHANT G. GHOSH
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Gravitational Collapse ◽  
Naked Singularity ◽  
De Sitter Spacetime ◽  
De Sitter ◽  
Btz Black Hole ◽  
Sitter Spacetime ◽  
Apparent Horizons ◽  
Sitter Background

We find an exact nonstatic charged BTZ-like solutions, in (N+1)-dimensional Einstein gravity in the presence of negative cosmological constant and a nonlinear Maxwell field defined by a power s of the Maxwell invariant, which describes the gravitational collapse of charged null fluid in an anti-de Sitter background. Considering the situation that a charged null fluid injects into the initially an anti-de Sitter spacetime, we show that a black hole form rather than a naked singularity, irrespective of spacetime dimensions, from gravitational collapse in accordance with cosmic censorship conjecture. The structure and locations of the apparent horizons of the black holes are also determined. It is interesting to see that, in the static limit and when N = 2, one can retrieve 2+1 BTZ black hole solutions.

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