H. T. Cho

A New Approach to Black Hole Quasinormal Modes: A Review of the Asymptotic Iteration Method

We discuss how to obtain black hole quasinormal modes (QNMs) using the asymptotic iteration method (AIM), initially developed to solve second-order ordinary differential equations. We introduce the standard version of this method and present an improvement more suitable for numerical implementation. We demonstrate that the AIM can be used to find radial QNMs for Schwarzschild, Reissner-Nordstrom (RN), and Kerr black holes in a unified way. We discuss some advantages of the AIM over the continued fractions method (CFM). This paper presents for the first time the spin 0, 1/2 and 2 QNMs of a Kerr black hole and the gravitational and electromagnetic QNMs of the RN black hole calculated via the AIM and confirms results previously obtained using the CFM. We also present some new results comparing the AIM to the WKB method. Finally we emphasize that the AIM is well suited to higher-dimensional generalizations and we give an example of doubly rotating black holes.

Black hole quasinormal modes using the asymptotic iteration method

In this paper we show that the asymptotic iteration method (AIM) allows one to numerically find the quasinormal modes of Schwarzschild and Schwarzschild de Sitter black holes. An added benefit of the method is that it can also be used to calculate the Schwarzschild anti-de Sitter quasinormal modes for the case of spin-zero perturbations. We also discuss an improved version of the AIM, more suitable for numerical implementation.

Split fermion quasinormal modes

In this paper we use the conformal properties of the spinor field to show how we can obtain the fermion quasinormal 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 quasinormal frequencies in both the large angular momentum and the large mode number limits.

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,

Asymptotic quasinormal frequencies of different spin fields in spherically symmetric black holes

n\ensuremath{\ge}3

Bulk dominated fermion emission on a Schwarzschild background

) for gray-body factors of Kerr\char21{}de Sitter black holes and for Hawking radiation from simply rotating (

Fermion excitations of a tense brane black hole

n+4

Asymptotic iteration method for spheroidal harmonics of higher-dimensional Kerr-(A)dS black holes

)-dimensional Kerr black holes. Although there is some subtlety with defining the Hawking temperature of a Kerr\char21{}de Sitter black hole, we present some preliminary results for emissions assuming the standard Hawking normalization and a Bousso-Hawking-like normalization.

Scalar field fluctuations in Schwarzschild–de Sitter spacetime

We consider the asymptotic quasinormal frequencies of various spin fields in Schwarzschild and Reissner-Nordstroem 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 nonextreme 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 1/4M for all the spin fields in the single-horizon cases of the Schwarzschild and the extreme Reissner-Nordstroem black holes. The implications of these results to the universality of the asymptotic quasinormal frequencies are discussed.

Quasi-exactly solvable quasinormal modes

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 then 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 setup we use is sufficiently general such that it could also easily be applied to any spherically symmetric background in