Quasinormal modes of a black hole surrounded by quintessence

Using the third-order WKB approximation, we evaluate the quasinormal frequencies of massless scalar field perturbation around the black hole which is surrounded by the static and spherically symmetric quintessence. Our result shows that due to the presence of quintessence, the scalar field damps more rapidly. Moreover, we also note that the quintessential state parameter $\epsilon$ (the ratio of pressure $p_q$ to the energy density $\rho_q$) play an important role for the quasinormal frequencies. As the state parameter $\epsilon$ increases the real part increases and the absolute value of the imaginary part decreases. This means that the scalar field decays more slowly in the larger $\epsilon$ quintessence case.Comment: 7 pages, 3 figure

Quasinormal Spectrum and Quantization of Charged Black Holes

Black-hole quasinormal modes have been the subject of much recent attention, with the hope that these oscillation frequencies may shed some light on the elusive theory of quantum gravity. We study {\it analytically} the asymptotic quasinormal spectrum of a {\it charged} scalar field in the (charged) Reissner-Nordstr\"om spacetime. We find an analytic expression for these black-hole resonances in terms of the black-hole physical parameters: its Bekenstein-Hawking temperature $T_{BH}$, and its electric potential $\Phi$. We discuss the applicability of the results in the context of black-hole quantization. In particular, we show that according to Bohr's correspondence principle, the asymptotic resonance corresponds to a fundamental area unit $\Delta A=4\hbar\ln2$.Comment: 4 page

Gravitational quasinormal modes for Kerr Anti-de Sitter black holes

We investigate the quasinormal modes for gravitational perturbations of rotating black holes in four dimensional Anti-de Sitter (AdS) spacetime. The study of the quasinormal frequencies related to these modes is relevant to the AdS/CFT correspondence. Although results have been obtained for Schwarzschild and Reissner-Nordstrom AdS black holes, quasinormal frequencies of Kerr-AdS black holes are computed for the first time. We solve the Teukolsky equations in AdS spacetime, providing a second order and a Pade approximation for the angular eigenvalues associated to the Teukolsky angular equation. The transformation theory and the Regge-Wheeler-Zerilli equations for Kerr-AdS are obtained.Comment: 20 pages, 13 figures, ReVTe

Intermediate Asymptotics of the Kerr Quasinormal Spectrum

We study analytically the quasinormal mode spectrum of near-extremal (rotating) Kerr black holes. We find an analytic expression for these black-hole resonances in terms of the black-hole physical parameters: its Bekenstein-Hawking temperature T_{BH} and its horizon's angular velocity \Omega, which is valid in the intermediate asymptotic regime 1<<\omega<<1/T_{BH}.Comment: 4 page

Comparing two approaches to Hawking radiation of Schwarzschild-de Sitter black holes

We study two different ways to analyze the Hawking evaporation of a Schwarzschild-de Sitter black hole. The first one uses the standard approach of surface gravity evaluated at the possible horizons. The second method derives its results via the Generalized Uncertainty Principle (GUP) which offers a yet different method to look at the problem. In the case of a Schwarzschild black hole it is known that this methods affirms the existence of a black hole remnant (minimal mass $M_{\rm min}$) of the order of Planck mass $m_{\rm pl}$ and a corresponding maximal temperature $T_{\rm max}$ also of the order of $m_{\rm pl}$. The standard $T(M)$ dispersion relation is, in the GUP formulation, deformed in the vicinity of Planck length $l_{\rm pl}$ which is the smallest value the horizon can take. We generalize the uncertainty principle to Schwarzschild-de Sitter spacetime with the cosmological constant $\varLambda=1/m_\varLambda^2$ and find a dual relation which, compared to $M_{\rm min}$ and $T_{\rm max}$, affirms the existence of a maximal mass $M_{\rm max}$ of the order $(m_{\rm pl}/m_\varLambda)m_{\rm pl}$, minimum temperature $T_{\rm min} \sim m_\varLambda$. As compared to the standard approach we find a deformed dispersion relation $T(M)$ close to $l_{\rm pl}$ and in addition at the maximally possible horizon approximately at $r_\varLambda=1/m_\varLambda$. $T(M)$ agrees with the standard results at $l_{\rm pl} \ll r \ll r_\varLambda$ (or equivalently at $M_{\rm min} \ll M \ll M_{\rm max}$).Comment: new references adde