513 research outputs found
Asymptotic Quasinormal Frequencies of Different Spin Fields in Spherically Symmetric Black Holes
We consider the asymptotic quasinormal frequencies of various spin fields in
Schwarzschild and Reissner-Nordstr\"om black holes. In the Schwarzschild case,
the real part of the asymptotic frequency is ln3 for the spin 0 and the spin 2
fields, while for the spin 1/2, the spin 1, and the spin 3/2 fields it is zero.
For the non-extreme charged black holes, the spin 3/2 Rarita-Schwinger field
has the same asymptotic frequency as that of the integral spin fields. However,
the asymptotic frequency of the Dirac field is different, and its real part is
zero. For the extremal case, which is relevant to the supersymmetric
consideration, all the spin fields have the same asymptotic frequency, the real
part of which is zero. For the imaginary parts of the asymptotic frequencies,
it is interesting to see that it has a universal spacing of for all the
spin fields in the single-horizon cases of the Schwarzschild and the extreme
Reissner-Nordstr\"om black holes. The implications of these results to the
universality of the asymptotic quasinormal frequencies are discussed.Comment: Revtex, 17 pages, 3 eps figures; one table, some remarks and
references added to section I
Exact Gravitational Quasinormal Frequencies of Topological Black Holes
We compute the exact gravitational quasinormal frequencies for massless
topological black holes in d-dimensional anti-de Sitter space. Using the gauge
invariant formalism for gravitational perturbations derived by Kodama and
Ishibashi, we show that in all cases the scalar, vector, and tensor modes can
be reduced to a simple scalar field equation. This equation is exactly solvable
in terms of hypergeometric functions, thus allowing an exact analytic
determination of the gravitational quasinormal frequencies.Comment: 14 pages, Latex; v2 additional reference
Dynamical evolution of a scalar field coupling to Einstein's tensor in the Reissner-Nordstr\"{o}m black hole spacetime
We study the dynamical evolution of a scalar field coupling to Einstein's
tensor in the background of Reissner-Nordstr\"{o}m black hole. Our results show
that the the coupling constant imprints in the wave dynamics of a scalar
perturbation. In the weak coupling, we find that with the increase of the
coupling constant the real parts of the fundamental quasinormal
frequencies decrease and the absolute values of imaginary parts increase for
fixed charge and multipole number . In the strong coupling, we find that
for the instability occurs when is larger than a certain
threshold value which deceases with the multipole number and
charge . However, for the lowest , we find that there does not exist
such a threshold value and the scalar field always decays for arbitrary
coupling constant.Comment: 11 pages, 6 figures, accepted for publication in Phys Rev
Quasinormal Modes of Kerr Black Holes in Four and Higher Dimensions
We analytically calculate to leading order the asymptotic form of quasinormal
frequencies of Kerr black holes in four, five and seven dimensions. All the
relevant quantities can be explicitly expressed in terms of elliptical
integrals. In four dimensions, we confirm the results obtained by Keshest and
Hod by comparing the analytic results to the numerical ones.Comment: 14 pages, 7 figure
Quasinormal modes of black holes localized on the Randall-Sundrum 2-brane
We investigate conformal scalar, electromagnetic, and massless Dirac
quasinormal modes of a brane-localized black hole. The background solution is
the four-dimensional black hole on a 2-brane that has been constructed by
Emparan, Horowitz, and Myers in the context of a lower dimensional version of
the Randall-Sundrum model. The conformally transformed metric admits a Killing
tensor, allowing us to obtain separable field equations. We find that the
radial equations take the same form as in the four-dimensional "braneless"
Schwarzschild black hole. The angular equations are, however, different from
the standard ones, leading to a different prediction for quasinormal
frequencies.Comment: 10 pages, 7 figures; references added, version to appear in PR
Perturbative calculation of quasi-normal modes of AdS Schwarzschild black holes
We calculate analytically quasi-normal modes of AdS Schwarzschild black holes
including first-order corrections. We consider massive scalar, gravitational
and electromagnetic perturbations. Our results are in good agreement with
numerical calculations. In the case of electromagnetic perturbations, ours is
the first calculation to provide an analytic expression for quasi-normal
frequencies, because the effective potential vanishes at zeroth order. We show
that the first-order correction is logarithmic.Comment: 20 pages incl. 8 figures (using eepic and color
The physical interpretation of the spectrum of black hole quasinormal modes
When a classical black hole is perturbed, its relaxation is governed by a set
of quasinormal modes with complex frequencies \omega= \omega_R+i\omega_I. We
show that this behavior is the same as that of a collection of damped harmonic
oscillators whose real frequencies are (\omega_R^2+\omega_I^2)^{1/2}, rather
than simply \omega_R. Since, for highly excited modes, \omega_I >> \omega_R,
this observation changes drastically the physical understanding of the black
hole spectrum, and forces a reexamination of various results in the literature.
In particular, adapting a derivation by Hod, we find that the area of the
horizon of a Schwarzschild black hole is quantized in units \Delta
A=8\pi\lpl^2, where \lpl is the Planck length (in contrast with the original
result \Delta A=4\log(3) \lpl^2). The resulting area quantization does not
suffer from a number of difficulties of the original proposal; in particular,
it is an intrinsic property of the black hole, independent of the spin of the
perturbation.Comment: 4 pages, 2 figures; v3: added references and comments. To appear in
Phys. Rev. Let
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