scholarly journals On the stability of the scalar field in the gravitational field of a rotating (Kerr-) black hole

2010 ◽  
Author(s):  
Reinhard Horst Beyer ◽  
H. A. Morales-Tecotl ◽  
L. A. Urena-Lopez ◽  
R. Linares-Romero ◽  
H. H. Garcia-Compean
Keyword(s):  
Black Hole ◽  
Gravitational Field ◽  
Scalar Field ◽  
Kerr Black Hole ◽  
The Stability

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 DISCUSSION ON SOME CHARACTERISTICS OF CHARGED BRANE-WORLD BLACK HOLES

2009 ◽  
Vol 24 (04) ◽  
pp. 719-739 ◽  
Author(s):  
M. KALAM ◽  
F. RAHAMAN ◽  
A. GHOSH ◽  
B. RAYCHAUDHURI
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Gravitational Field ◽  
Scalar Field ◽  
Brane World ◽  
Massless Scalar ◽  
Massless Scalar Field ◽  
Effective Potentials ◽  
Test Particles ◽  
Jacobi Formalism

Several physical natures of charged brane-world black holes are investigated. Firstly, the timelike and null geodesics of the charged brane-world black holes are presented. We also analyze all the possible motions by plotting the effective potentials for various parameters for circular and radial geodesics. Secondly, we investigate the motion of test particles in the gravitational field of the charged brane-world black holes using the Hamilton–Jacobi formalism. We consider charged and uncharged test particles and examine their behavior in both static and nonstatic cases. Thirdly, the thermodynamics of the charged brane-world black holes are studied. Finally, it is shown that there is no phenomenon of superradiance for an incident massless scalar field for such a black hole.

A Kerr black hole in the external gravitational field

1997 ◽  
Vol 230 (1-2) ◽  
pp. 7-11 ◽  
Author(s):  
Nora Bretón ◽  
Tatiana E. Denisova ◽  
Vladimir S. Manko
Keyword(s):  
Black Hole ◽  
Gravitational Field ◽  
Kerr Black Hole ◽  
External Gravitational Field

scholarly journals The limit y of the incident particle under the superradiance of Kerr black hole

2021 ◽  
Author(s):  
Wen-Xiang Chen
Keyword(s):  
Black Hole ◽  
Scalar Field ◽  
Kerr Black Hole ◽  
Weak Field ◽  
Incident Particle ◽  
Field Coupling ◽  
Field System ◽  
Field Behavior

It is important to emphasize that as the reference has proved well, the critical storage line of black hole field system is universal, that is, different scalar field coupling functions with the same weak field behavior are $\{C(\phi) \} , C (\phi) =1+\alpha\phi ^{2} + o(\phi ^{4})$, and have the same function behavior $\alpha=\alpha (\mu); a / M) $. The purpose of this paper is to find out the limit $y$ of the incident particle under the superradiance of the preset boundary (${\mu} = {y}{\omega}$).

Thermal Casimir effect in the Kerr spacetime with quintessence

2019 ◽  
Vol 34 (16) ◽  
pp. 1950125
Author(s):  
V. B. Bezerra ◽  
J. M. Toledo
Keyword(s):  
Black Hole ◽  
Scalar Field ◽  
Equatorial Plane ◽  
Casimir Effect ◽  
Kerr Black Hole ◽  
Casimir Energy ◽  
Massless Scalar ◽  
Massless Scalar Field ◽  
Kerr Spacetime

We calculate thermal corrections to the Casimir energy of a massless scalar field in the Kerr black hole surrounded by quintessence, taking into account the metrics derived by Ghosh [S. G. Ghosh, Eur. Phys. J. C 76, 222 (2016)] and Toshmatov et al. [B. Toshmatov, Z. Stuchlík and B. Ahmedov, Eur. Phys. J. Plus 132, 98 (2017)]. We compare both results and show that they are almost the same, except very close to the horizons. At [Formula: see text], equatorial plane, the results are the same, as should be expected, due to the fact that the metrics coincide in this region.

scholarly journals QUANTUM AMPLITUDES IN BLACK-HOLE EVAPORATION: COMPLEX APPROACH AND SPIN-0 AMPLITUDE

2011 ◽  
Vol 20 (02) ◽  
pp. 133-159
Author(s):  
A. N. St. J. FARLEY ◽  
P. D. D'EATH
Keyword(s):  
Black Hole ◽  
Gravitational Field ◽  
Scalar Field ◽  
Boundary Value Problem ◽  
Boundary Data ◽  
Proper Time ◽  
Boundary Value ◽  
Constrained Systems ◽  
Time Interval ◽  
Late Time

This paper is concerned with the quantum-mechanical decay of a Schwarzschild-like black hole, formed by gravitational collapse, into almost-flat space–time and weak radiation at a very late time. We evaluate quantum amplitudes (not just probabilities) for transitions from initial to final states. This quantum description shows that no information is lost in collapse to a black hole. Boundary data for the gravitational field and (in this paper) a scalar field are posed on an initial space-like hypersurface ΣI and a final surface ΣF. These asymptotically flat three-surfaces are separated by a Lorentzian proper-time interval T (typically very large), as measured at spatial infinity. The boundary-value problem is made well-posed, both classically and quantum-mechanically, by a rotation of T into the lower-half complex plane: T → |T| exp (- iθ), with 0 < θ ≤ π/2. This corresponds to Feynman's +iϵ prescription. We consider the classical boundary-value problem and calculate the second-variation classical Lorentzian action [Formula: see text] as a functional of the boundary data. Following Feynman, the Lorentzian quantum amplitude is recovered in the limit θ → 0+ from the well-defined complex-T amplitude. Dirac's canonical approach to the quantisation of constrained systems shows that, for locally supersymmetric theories of gravity, the amplitude is exactly semi-classical, namely [Formula: see text] for weak perturbations, apart from delta functionals of the supersymmetry constraints. We treat such quantum amplitudes for weak scalar-field configurations on ΣF, taking (for simplicity) the weak final gravitational field to be spherically symmetric. The treatment involves adiabatic solutions to the scalar wave equation. This considerably extends work reported in previous papers, by giving explicit expressions for the real and imaginary parts of such quantum amplitudes.

scholarly journals Comments on “Casimir effect in the Kerr spacetime with quintessence”

2017 ◽  
Vol 32 (21) ◽  
pp. 1775001 ◽  
Author(s):  
Bobir Toshmatov ◽  
Zdeněk Stuchlík ◽  
Bobomurat Ahmedov
Keyword(s):  
Black Hole ◽  
Scalar Field ◽  
Casimir Effect ◽  
Kerr Black Hole ◽  
Casimir Energy ◽  
Massless Scalar ◽  
Massless Scalar Field ◽  
Kerr Spacetime ◽  
The Difference

This comment is devoted to the recalculation of the Casimir energy of a massless scalar field in the Kerr black hole surrounded by quintessence derived in [B. Toshmatov, Z. Stuchlík and B. Ahmedov, Eur. Phys. J. Plus 132, 98 (2017)] and its comparison with the results recently obtained in [V. B. Bezerra, M. S. Cunha, L. F. F. Freitas and C. R. Muniz, Mod. Phys. Lett. A 32, 1750005 (2017)] in the spacetime [S. G. Ghosh, Eur. Phys. J. C 76, 222 (2016)]. We have shown that in the more realistic spacetime which does not have the failures illustrated here, the Casimir energy is significantly bigger than that derived in [V. B. Bezerra, M. S. Cunha, L. F. F. Freitas and C. R. Muniz, Mod. Phys. Lett. A 32, 1750005 (2017)], and the difference becomes crucial especially in the regions of near horizons of the spacetime.

GRAVITOMAGNETISM AND THE BERRY PHASE OF PHOTON IN AN ROTATING GRAVITATIONAL FIELD

2001 ◽  
Vol 10 (06) ◽  
pp. 961-969 ◽  
Author(s):  
LONG-LONG FENG ◽  
WOLUNG LEE
Keyword(s):  
Black Hole ◽  
Gravitational Field ◽  
Berry Phase ◽  
Optical Rotation ◽  
Polarized Light ◽  
Kerr Black Hole ◽  
Optical Path ◽  
Zeroth Order ◽  
Helicity State ◽  
Two Factors

In this paper, we present an investigation of the Berry phase that a photon acquired during its propagating through a gravitational field produced by a Kerr black hole. Starting from the Maxwell equation in Kerr–Schild metric form of Kerr black hole, we give the zeroth order Hamiltonian of the photon under geometric optics approximation. The helicity state of the photon is then derived. We demonstrate that there are two factors leading to the Berry phase that the photon acquires in a gravitational field. These are the adiabatic transport of the local comoving tetrad and the rotation of the equivalent magnetic field that we introduce. The straightforward calculation show that the appearance of Berry phase is attributed to the twisted optical path due to the rotation of black hole. It is in fact analogous to the observed optical rotation for a linear polarized light propagating in an helical optical fiber.

Superradiant stability of the Kerr black hole

2020 ◽  
Vol 29 (01) ◽  
pp. 2050009 ◽  
Author(s):  
Wen-Xiang Chen ◽  
Zi-Yang Huang
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Kerr Black Hole ◽  
Algebraic Methods ◽  
Stability Conditions ◽  
Parameter Region ◽  
Kerr Black Holes ◽  
The Stability ◽  
Scalar Perturbations

We know that Kerr black holes are stable for specific conditions. In this paper, we use algebraic methods to prove the stability of the Kerr black hole against certain scalar perturbations. This provides new results for the previously obtained superradiant stability conditions of Kerr black hole. Hod proved that Kerr black holes are stable to massive perturbations in the regime [Formula: see text]. In this paper, we consider some other situations of the stability of the black hole in the complementary parameter region[Formula: see text]

Sign in / Sign up

Export Citation Format

Share Document