scholarly journals SEMICLASSICAL (QFT) AND QUANTUM (STRING) ROTATING BLACK HOLES AND THEIR EVAPORATION: NEW RESULTS

2007 ◽  
Vol 22 (08n09) ◽  
pp. 1627-1648 ◽  
Author(s):  
A. BOUCHAREB ◽  
M. RAMÓN MEDRANO ◽  
N. G. SÁNCHEZ
Keyword(s):  
Phase Transition ◽  
Black Hole ◽  
Angular Momentum ◽  
Emission Cross Section ◽  
Kerr Black Hole ◽  
Hawking Temperature ◽  
Extremal Black Hole ◽  
Entropy Formula ◽  
Newman Black Hole ◽  
String State

Combination of both quantum field theory (QFT) and string theory in curved backgrounds in a consistent framework, the string analogue model, allows us to provide a full picture of the Kerr–Newman black hole and its evaporation going beyond the current picture. We compute the quantum emission cross-section of strings by a Kerr–Newman black hole (KNbh). It shows the black hole emission at the Hawking temperature T sem in the early stage of evaporation and the new string emission featuring a Hagedorn transition into a string state of temperature Ts at the last stages. New bounds on J and Q emerge in the quantum string regime (besides the known ones of the classical/semiclassical QFT regime). The last state of evaporation of a semiclassical Kerr–Newman black hole with mass M > m Pl , angular momentum J and charge Q is a string state of temperature Ts, string mass Ms, J = 0 and Q = 0, decaying as usual quantum strings do into all kinds of particles. (Naturally, in this framework, there is no loss of information, (there is no paradox at all).) We compute the string entropy Ss(m, j) from the microscopic string density of states of mass m and spin mode j, ρ(m, j). (Besides the Hagedorn transition at Ts) we find for high j (extremal string states j → m2α′c), a new phase transition at a temperature [Formula: see text], higher than Ts. By precisely identifying the semiclassical and quantum (string) gravity regimes, we find a new formula for the Kerr black hole entropy S sem (M, J), as a function of the usual Bekenstein–Hawking entropy [Formula: see text]. For M ≫ m Pl and J < GM2/c, [Formula: see text] is the leading term, but for high angular momentum, (nearly extremal case J = GM2/c), a gravitational phase transition operates and the whole entropy S sem is drastically different from the Bekenstein–Hawking entropy [Formula: see text]. This new extremal black hole transition occurs at a temperature T sem J = (J/ℏ)T sem , higher than the Hawking temperature T sem .

scholarly journals SEMICLASSICAL (QUANTUM FIELD THEORY) AND QUANTUM (STRING) DE SITTER REGIMES: NEW RESULTS

2007 ◽  
Vol 16 (06) ◽  
pp. 1053-1074 ◽  
Author(s):  
A. BOUCHAREB ◽  
M. RAMÓN MEDRANO ◽  
N. G. SÁNCHEZ
Keyword(s):  
Phase Transition ◽  
Black Hole ◽  
Emission Cross Section ◽  
Hubble Constant ◽  
Flat Space ◽  
De Sitter Space ◽  
Space Time ◽  
De Sitter ◽  
Entropy Formula ◽  
New Phase

We compute the quantum string entropy S s (m, H) from the microscopic string density of states ρ s (m, H) of mass m in de Sitter space–time. We find for high m (high Hm → c/α') a new phase transition at the critical string temperature T s = (1/2πk B )L cl c2/α', higher than the flat space (Hagedorn) temperature t s (L cl = c/H, the Hubble constant H acts at the transition, producing a smaller string constant α' and thus, a higher tension). T s is the precise quantum dual of the semiclassical (QFT Hawking–Gibbons) de Sitter temperature T sem = ħ c/(2πk B L cl ). By precisely identifying the semiclassical and quantum (string) de Sitter regimes, we find a new formula for the full de Sitter entropy S sem (H), as a function of the usual Bekenstein–Hawking entropy [Formula: see text]. For L cl ≫ ℓ Planck , i.e. for low [Formula: see text] is the leading term, but for high H near c/ℓ Planck , a new phase transition operates and the whole entropy S sem (H) is drastically different from the Bekenstein–Hawking entropy [Formula: see text]. We compute the string quantum emission cross-section σ string by a black hole in de Sitter (or asymptotically de Sitter) space–time (bhdS). For T sem bhdS ℓ T s (early evaporation stage), it shows the QFT Hawking emission with temperature T sem bhdS (semiclassical regime). For T sem bhdS → T s , σ string exhibits a phase transition into a string de Sitter state of size [Formula: see text], [Formula: see text], and string de Sitter temperature T s . Instead of featuring a single pole singularity in the temperature (Carlitz transition), it features a square root branch point (de Vega–Sanchez transition). New bounds on the black hole radius r g emerge in the bhdS string regime: it can become r g = L s /2, or it can reach a more quantum value, r g = 0.365 ℓ s .

scholarly journals HOLLOWGRAPHY DRIVEN HOLOGRAPHY: BLACK HOLE WITH VANISHING VOLUME INTERIOR

2010 ◽  
Vol 19 (14) ◽  
pp. 2345-2351 ◽  
Author(s):  
AHARON DAVIDSON ◽  
ILYA GURWICH
Keyword(s):  
Phase Transition ◽  
General Relativity ◽  
Black Hole ◽  
Degrees Of Freedom ◽  
Schwarzschild Solution ◽  
Entropy Formula ◽  
Gravitational Theories ◽  
Hollow Interior ◽  
Spatial Volume ◽  
Self Similar

Hawking–Bekenstein entropy formula seems to tell us that no quantum degrees of freedom can reside in the interior of a black hole. We suggest that this is a consequence of the fact that the volume of any interior sphere of finite surface area simply vanishes. Obviously, this is not the case in general relativity. However, we show that such a phenomenon does occur in various gravitational theories which admit a spontaneously induced general relativity. In such theories, due to a phase transition (one-parameter family degenerates) which takes place precisely at the would-have-been horizon, the recovered exterior Schwarzschild solution connects, by means of a self-similar transition profile, with a novel "hollow" interior exhibiting a vanishing spatial volume and a locally varying Newton constant. This constitutes the so-called "hollowgraphy" driven holography.

Bound orbits around modified Hayward black holes

2021 ◽  
Author(s):  
Bo Gao ◽  
Xue-Mei Deng
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Angular Momentum ◽  
Gravitational Field ◽  
Periodic Orbits ◽  
Kerr Black Hole ◽  
Periodic Oscillations ◽  
Test Particles ◽  
Spin Parameter ◽  
Bound Orbits

The neutral time-like particle’s bound orbits around modified Hayward black holes have been investigated. We find that both in the marginally bound orbits (MBO) and the innermost stable circular orbits (ISCO), the test particle’s radius and its angular momentum are all more sensitive to one of the parameters [Formula: see text]. Especially, modified Hayward black holes with [Formula: see text] could mimic the same ISCO radius around the Kerr black hole with the spin parameter up to [Formula: see text]. Small [Formula: see text] could mimic the ISCO of small-spinning test particles around Schwarzschild black holes. Meanwhile, rational (periodic) orbits around modified Hayward black holes have also been studied. The epicyclic frequencies of the quasi-circular motion around modified Hayward black holes are calculated and discussed with respect to the observed Quasi-periodic oscillations (QPOs) frequencies. Our results show that rational orbits around modified Hayward black holes have different values of the energy from the ones of Schwarzschild black holes. The epicyclic frequencies in modified Hayward black holes have different frequencies from Schwarzschild and Kerr ones. These might provide hints for distinguishing modified Hayward black holes from Schwarzschild and Kerr ones by using the dynamics of time-like particles around the strong gravitational field.

scholarly journals Spectroscopy of z=0 Lifshitz Black Hole

2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Gulnihal Tokgoz ◽  
Izzet Sakalli
Keyword(s):  
Exact Solution ◽  
Black Hole ◽  
Normal Modes ◽  
Hawking Temperature ◽  
Massive Scalar ◽  
Local Mass ◽  
Entropy Formula ◽  
Adiabatic Invariant Quantity ◽  
Lifshitz Black Hole ◽  
Area Spectra

We studied the thermodynamics and spectroscopy of a 4-dimensional, z=0 Lifshitz black hole (Z0LBH). Using Wald’s entropy formula and the Hawking temperature, we derived the quasi-local mass of the Z0LBH. Based on the exact solution to the near-horizon Schrödinger-like equation (SLE) of the massive scalar waves, we computed the quasi-normal modes of the Z0LBH via employing the adiabatic invariant quantity for the Z0LBH. This study shows that the entropy and area spectra of the Z0LBH are equally spaced.

scholarly journals Quantum gravity effect on the Hawking radiation of spinning dilaton black hole

2019 ◽  
Vol 79 (10) ◽  
Author(s):  
Ganim Gecim ◽  
Yusuf Sucu
Keyword(s):  
Black Hole ◽  
Angular Momentum ◽  
Quantum Gravity ◽  
Total Angular Momentum ◽  
Vector Boson ◽  
Scalar Particle ◽  
Dirac Particle ◽  
Hawking Temperature ◽  
Quantum Gravity Effect ◽  
Dilaton Black Hole

Abstract The quantum gravity correction to the Hawking temperature of the 2+1 dimensional spinning dilaton black hole is studied by using the Hamilton-Jacobi approach in the context of the Generalized Uncertainty Principle (GUP). It is observed that the modified Hawking temperature of the black hole depends on both black hole and the tunnelling particle properties. Moreover, it is observed that the mass and the angular momentum of the scalar particle have the same effect on the Hawking temperature of the black hole, while the mass and total angular momentum (orbital+spin) of Dirac particle have different effect. Furthermore, the mass and total angular momentum (orbital+spin) of vector boson particle have a similar effect that of Dirac particle. Also, thermodynamical stability and phase transition of the black hole are discussed for scalar, Dirac and vector boson in the context of GUP, respectively. And, it is observed that the scalar particle probes the black hole as stable whereas, as for Dirac and vector boson particles, it might undergoes second-type phase transition to become stable while in the absence of the quantum gravity effect all of these particle probes the black hole as stable.

scholarly journals The GUP Effect on Tunneling of Massive Vector Bosons from The 2+1 Dimensional Black Hole

2018 ◽  
Vol 2018 ◽  
pp. 1-8
Author(s):  
Ganim Gecim ◽  
Yusuf Sucu
Keyword(s):  
Black Hole ◽  
Angular Momentum ◽  
Total Angular Momentum ◽  
Vector Boson ◽  
Generalized Uncertainty Principle ◽  
Hawking Temperature ◽  
Massive Vector ◽  
Vector Bosons ◽  
Dimensional Black Hole ◽  
The Stability

In this study, the Generalized Uncertainty Principle (GUP) effect on the Hawking radiation formed by tunneling of a massive vector boson particle from the 2+1 dimensional new-type black hole was investigated. We used modified massive vector boson equation based on the GUP. Then, the Hamilton-Jacobi quantum tunneling approach was used to work out the tunneling probability of the massive vector boson particle and Hawking temperature of the black hole. Due to the GUP effect, the modified Hawking temperature was found to depend on the black hole properties, on the AdS3 radius, and on the energy, mass, and total angular momentum of the tunneling massive vector boson. In the light of these results, we also observed that modified Hawking temperature increases by the total angular momentum of the particle while it decreases by the energy and mass of the particle and the graviton mass. Also, in the context of the GUP, we see that the Hawking temperature due to the tunneling massive vector boson is completely different from both that of the spin-0 scalar and that of the spin-1/2 Dirac particles obtained in the previous study. We also calculate the heat capacity of the black hole using the modified Hawking temperature and then discuss influence of the GUP on the stability of the black hole.

Modified fermion tunneling radiation of Demianski–Newman black hole at higher energy scales

2019 ◽  
Vol 35 (10) ◽  
pp. 2050061
Author(s):  
Z. Luo ◽  
X. G. Lan
Keyword(s):  
Black Hole ◽  
Dispersion Relation ◽  
Jacobi Equation ◽  
Black Hole Entropy ◽  
Hawking Temperature ◽  
Tunneling Radiation ◽  
Black Hole Spacetime ◽  
Newman Black Hole ◽  
Hamilton Jacobi Equation

It is suggested that the dispersion relation might be corrected at higher energy scales and lead to the deformed Hamilton–Jacobi equation. In this paper, we use the correction to investigate the fermion tunneling radiation for Demianski–Newman black hole spacetime, and the result shows that the corresponding Hawking temperature and the black hole entropy are related to the angular parameters of the black hole coordinates.

scholarly journals Optical properties of Kerr–Newman spacetime in the presence of plasma

2020 ◽  
Vol 80 (8) ◽  
Author(s):  
Gulmina Zaman Babar ◽  
Abdullah Zaman Babar ◽  
Farruh Atamurotov
Keyword(s):  
Black Hole ◽  
Kerr Black Hole ◽  
Field Approximation ◽  
Weak Field ◽  
Jacobi Method ◽  
Plasma Parameters ◽  
Spin Parameter ◽  
Newman Black Hole ◽  
Shadow Cast ◽  
Thermal Radiations

Abstract We have studied the null geodesics in the background of the Kerr–Newman black hole veiled by a plasma medium using the Hamilton–Jacobi method. The influence of black hole’s charge and plasma parameters on the effective potential and the generic photon orbits has been investigated. Furthermore, our discussion embodies the effects of black hole’s charge, plasma and the inclination angle on the shadow cast by the gravity with and without the spin parameter. We examined the energy released from the black hole as a result of the thermal radiations, which exclusively depends on the size of the shadow. The angle of deflection of the massless particles is also explored considering a weak-field approximation. We present our results in juxtaposition to the analogous black holes in General Relativity, particularly the Schwarzschild and Kerr black hole.

scholarly journals SEMICLASSICAL CORRECTIONS TO THE CARDY–VERLINDE FORMULA OF KERR BLACK HOLES

2008 ◽  
Vol 23 (13) ◽  
pp. 2047-2053 ◽  
Author(s):  
M. R. SETARE
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Central Charge ◽  
Kerr Black Hole ◽  
Gravitational Effect ◽  
The Self ◽  
Entropy Formula ◽  
Verlinde Formula ◽  
Kerr Black Holes

In this paper, we compute the corrections to the Cardy–Verlinde formula of four-dimensional Kerr black hole. These corrections are considered within the context of KKW analysis and arise as a result of the self-gravitational effect. Then we show that one can take into account the semiclassical corrections of the Cardy–Verlinde entropy formula by only redefining the Virasoro operator L0 and the central charge c.

Sign in / Sign up

Export Citation Format

Share Document