4,941 research outputs found
Black hole quasinormal modes using the asymptotic iteration method
In this article we show that the asymptotic iteration method (AIM) allows one
to numerically find the quasinormal modes of Schwarzschild and Schwarzschild de
Sitter (SdS) black holes. An added benefit of the method is that it can also be
used to calculate the Schwarzschild anti-de Sitter (SAdS) quasinormal modes for
the case of spin zero perturbations. We also discuss an improved version of the
AIM, more suitable for numerical implementation.Comment: 10 pages, LaTeX; references added; substantially expanded versio
Split fermion quasi-normal modes
In this paper we use the conformal properties of the spinor field to show how
we can obtain the fermion quasi-normal modes for a higher dimensional
Schwarzschild black hole. These modes are of interest in so called split
fermion models, where quarks and leptons are required to exist on different
branes in order to keep the proton stable. As has been previously shown, for
brane localized fields, the larger the number of dimensions the faster the
black hole damping rate. Moreover, we also present the analytic forms of the
quasi-normal frequencies in both the large angular momentum and the large mode
number limits.Comment: 11 pages, 7 figures, version 2 added reference
Graviton emission from simply rotating Kerr-de Sitter black holes: Transverse traceless tensor graviton modes
In this article we present results for tensor graviton modes (in seven
dimensions and greater, ) for greybody factors of Kerr-dS black holes
and for Hawking radiation from simply rotating (n+4)-dimensional Kerr black
holes. Although there is some subtlety with defining the Hawking temperature of
a Kerr-dS black hole, we present some preliminary results for emissions
assuming the standard Hawking normalization and a Bousso-Hawking-like
normalization.Comment: 12 pages, 18 figure
Angular Eigenvalues of Higher-Dimensional Kerr-(A)dS Black Holes with Two Rotations
In this paper, following the work of Chen, L\"u and Pope, we present the
general metric for Kerr-(A)dS black holes with two rotations. The corresponding
Klein-Gordon equation is separated explicitly, from which we develop
perturbative expansions for the angular eigenvalues in powers of the rotation
parameters with .Comment: 10 pages, no figures. To appear in the proceedings of 2011 Shanghai
Asia-Pacific School and Workshop on Gravitatio
Bulk dominated fermion emission on a Schwarzschild background
Using the WKBJ approximation, and the Unruh method, we obtain semi-analytic
expressions for the absorption probability (in all energy regimes) for Dirac
fermions on a higher dimensional Schwarzschild background. We present an
analytic expression relating the absorption probability to the absorption
cross-section, and then use these results to plot the emission rates to third
order in the WKBJ approximation. The set-up we use is sufficiently general such
that it could also easily be applied to any spherically symmetric background in
-dimensions. Our results lead to the interesting conclusion that for
bulk fermion emission dominates brane localised emission. This is an example
contrary to the conjecture that black holes radiate mainly on the brane.Comment: 13 pages, 3 figure
Gravitino fields in Schwarzschild black hole spacetimes
The analysis of gravitino fields in curved spacetimes is usually carried out
using the Newman-Penrose formalism. In this paper we consider a more direct
approach with eigenspinor-vectors on spheres, to separate out the angular parts
of the fields in a Schwarzschild background. The radial equations of the
corresponding gauge invariant variable obtained are shown to be the same as in
the Newman-Penrose formalism. These equations are then applied to the
evaluation of the quasinormal mode frequencies, as well as the absorption
probabilities of the gravitino field scattering in this background.Comment: 21 pages, 2 figures. arXiv admin note: text overlap with
arXiv:1006.3327 by other author
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