scholarly journals Quasinormal modes of dilatonic Reissner–Nordström black holes

2019 ◽  
Vol 79 (12) ◽  
Author(s):  
Jose Luis Blázquez-Salcedo ◽  
Sarah Kahlen ◽  
Jutta Kunz
Keyword(s):  
Black Holes ◽  
Quantitative Analysis ◽  
Electric Charge ◽  
Quasinormal Modes ◽  
Spherically Symmetric ◽  
Coupling Constant ◽  
Dilaton Coupling

AbstractWe calculate the quasinormal modes of static spherically symmetric dilatonic Reissner–Nordström black holes for general values of the electric charge and of the dilaton coupling constant. The spectrum of quasinormal modes is composed of five families of modes: polar and axial gravitational-led modes, polar and axial electromagnetic-led modes, and polar scalar-led modes. We make a quantitative analysis of the spectrum, revealing its dependence on the electric charge and on the dilaton coupling constant. For large electric charge and large dilaton coupling, strong deviations from the Reissner–Nordström modes arise. In particular, isospectrality is strongly broken, both for the electromagnetic-led and the gravitational-led modes, for large values of the charge.

scholarly journals Quasinormal Modes of Charged Black Holes in Higher-Dimensional Einstein-Power-Maxwell Theory

Axioms ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 33 ◽  
Author(s):  
Grigoris Panotopoulos
Keyword(s):  
Black Holes ◽  
Scalar Field ◽  
Electric Charge ◽  
Quasinormal Modes ◽  
Space Time ◽  
Maxwell Theory ◽  
Charged Black Holes ◽  
Higher Dimensional ◽  
The Impact ◽  
Scalar Perturbations

We compute the quasinormal frequencies for scalar perturbations of charged black holes in five-dimensional Einstein-power-Maxwell theory. The impact on the spectrum of the electric charge of the black holes, of the angular degree, of the overtone number, and of the mass of the test scalar field is investigated in detail. The quasinormal spectra in the eikonal limit are computed as well for several different space-time dimensionalities.

scholarly journals Asymptotic quasinormal modes of string-theoretical d-dimensional black holes

2021 ◽  
Vol 2021 (8) ◽  
Author(s):  
Filipe Moura ◽  
João Rodrigues
Keyword(s):  
Differential Equation ◽  
Black Holes ◽  
Complex Plane ◽  
Quasinormal Modes ◽  
Scalar Fields ◽  
Einstein Gravity ◽  
Quasinormal Mode ◽  
Spherically Symmetric ◽  
Gravitational Perturbations

Abstract We compute the quasinormal frequencies of d-dimensional spherically symmetric black holes with leading string α′ corrections for tensorial gravitational perturbations in the highly damped regime. We solve perturbatively the master differential equation and we compute the monodromies of the master perturbation variable (analytically continued to the complex plane) in different contours, in order to obtain the quasinormal mode spectra. We proceed analogously for the quasinormal modes of test scalar fields. Differently than in Einstein gravity, we obtain distinct results for the two cases.

scholarly journals Scalar Perturbations of Black Holes in the f(R)=R−2αR Model

Universe ◽  
2022 ◽  
Vol 8 (1) ◽  
pp. 47
Author(s):  
Ping Li ◽  
Rui Jiang ◽  
Jian Lv ◽  
Xianghua Zhai
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Scalar Field ◽  
Critical Frequency ◽  
Amplification Factor ◽  
Quasinormal Modes ◽  
Spherically Symmetric ◽  
Third Order ◽  
Charged Scalar ◽  
The Time Domain

In this paper, we study the perturbations of the charged static spherically symmetric black holes in the f(R)=R−2αR model by a scalar field. We analyze the quasinormal modes spectrum, superradiant modes, and superradiant instability of the black holes. The frequency of the quasinormal modes is calculated in the frequency domain by the third-order WKB method, and in the time domain by the finite difference method. The results by the two methods are consistent and show that the black hole stabilizes quicker for larger α satisfying the horizon condition. We then analyze the superradiant modes when the massive charged scalar field is scattered by the black hole. The frequency of the superradiant wave satisfies ω∈(μ2,ωc), where μ is the mass of the scalar field, and ωc is the critical frequency of the superradiance. The amplification factor is also calculated by numerical method. Furthermore, the superradiant instability of the black hole is studied analytically, and the results show that there is no superradiant instability for such a system.

scholarly journals Perturbative and nonperturbative quasinormal modes of 4D Einstein–Gauss–Bonnet black holes

2020 ◽  
Vol 80 (8) ◽  
Author(s):  
Almendra Aragón ◽  
Ramón Bécar ◽  
P. A. González ◽  
Yerko Vásquez
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Imaginary Part ◽  
Quasinormal Modes ◽  
Scalar Fields ◽  
The Other ◽  
Coupling Constant ◽  
De Sitter ◽  
Other Hand

Abstract We study the propagation of probe scalar fields in the background of 4D Einstein–Gauss–Bonnet black holes with anti-de Sitter (AdS) asymptotics and calculate the quasinormal modes. Mainly, we show that the quasinormal spectrum consists of two different branches, a branch perturbative in the Gauss–Bonnet coupling constant $$\alpha $$α and another branch, nonperturbative in $$\alpha $$α. The perturbative branch consists of complex quasinormal frequencies that approximate the quasinormal frequencies of the Schwarzschild AdS black hole in the limit of a null coupling constant. On the other hand, the nonperturbative branch consists of purely imaginary frequencies and is characterized by the growth of the imaginary part when $$\alpha $$α decreases, diverging in the limit of null coupling constant; therefore they do not exist for the Schwarzschild AdS black hole. Also, we find that the imaginary part of the quasinormal frequencies is always negative for both branches; therefore, the propagation of scalar fields is stable in this background.

scholarly journals On Quasinormal Modes for Scalar Perturbations of Static Spherically Symmetric Black Holes in Nash Embedding Framework

2017 ◽  
Vol 2017 ◽  
pp. 1-10
Author(s):  
Sergio C. Ulhoa ◽  
Ronni G. G. Amorim ◽  
Abraão J. S. Capistrano
Keyword(s):  
Black Holes ◽  
Quasinormal Modes ◽  
Wkb Approximation ◽  
Spherically Symmetric ◽  
Third Order ◽  
Five Dimensions ◽  
The Third ◽  
Bulk Space ◽  
Scalar Perturbations

In this paper we investigate scalar perturbations of black holes embedded in a five-dimensional bulk space. The quasinormal frequencies of such black holes are calculated using the third order of Wentzel, Kramers, and Brillouin (WKB) approximation for scalar perturbations. The high overtones of quasinormal modes indicate a resonant-like set of black holes suggesting a serious constraint of embedding models in five dimensions.

scholarly journals Black holes in Einstein-Gauß-Bonnet-dilaton theory

2016 ◽  
Vol 12 (S324) ◽  
pp. 265-272 ◽  
Author(s):  
Jose Luis Blázquez-Salcedo ◽  
Vitor Cardoso ◽  
Valeria Ferrari ◽  
Leonardo Gualtieri ◽  
Panagiota Kanti ◽  
...  
Keyword(s):  
Black Holes ◽  
Angular Momentum ◽  
Strong Evidence ◽  
Quasinormal Modes ◽  
Coupling Constant ◽  
X Ray ◽  
Orbital Frequency ◽  
Low Mass ◽  
Bonnet Term ◽  
Current Bound

AbstractGeneralizations of the Schwarzschild and Kerr black holes are discussed in an astrophysically viable generalized theory of gravity, which includes higher curvature corrections in the form of the Gauss-Bonnet term, coupled to a dilaton. The angular momentum of these black holes can slightly exceed the Kerr bound. The location and the orbital frequency of particles in their innermost stable circular orbits can deviate significantly from the respective Kerr values. Study of the quasinormal modes of the static black holes gives strong evidence that they are mode stable against polar and axial perturbations. Future gravitational wave observations should improve the current bound on the Gauss-Bonnet coupling constant, based on observations of the low-mass x-ray binary A 0620-00.

scholarly journals SPACING OF THE ENTROPY SPECTRUM FOR KS BLACK HOLE IN HOŘAVA–LIFSHITZ GRAVITY

2011 ◽  
Vol 26 (02) ◽  
pp. 151-159 ◽  
Author(s):  
M. R. SETARE ◽  
D. MOMENI
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Mass Parameter ◽  
Quasinormal Modes ◽  
Surface Gravity ◽  
Spherically Symmetric ◽  
Entropy Spectrum ◽  
Adiabatic Invariance ◽  
Fundamental Parameters ◽  
Symmetric Spacetime

In this paper we present the spectrum of entropy/area for Kehagias–Sfetsos (KS) black hole in Hořava–Lifshitz (HL) gravity via quasinormal modes (QNM) approach. We show that in the massive case, the mass parameter μ disappears in the entropy spectrum and the quasinormal modes are modified by a term proportional to the mass square term. Our calculations show that the charge-like parameter [Formula: see text] appears in the surface gravity and our calculations can be applied to any spherically symmetric spacetime which has only one physically acceptable horizon. Our main difference between our calculations and what was done in Ref. 1 is that we explicitly calculated the portion of charge and mass on the surface gravity and consequently in the QNM expression. Since the imaginary part of the QNM is related to the adiabatic invariance of the system and also to the entropy, surprisingly the mass parameter does not appear in the entropy spectrum. Our conclusion supported by some acclaims about the scalar field parameters (charges) cannot change the fundamental parameters in the four-dimensional black holes.

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