scholarly journals Gravitational Quasinormal Modes of Regular Phantom Black Hole

2017 ◽  
Vol 2017 ◽  
pp. 1-19 ◽  
Author(s):  
Jin Li ◽  
Kai Lin ◽  
Hao Wen ◽  
Wei-Liang Qian
Keyword(s):  
Black Hole ◽  
Scalar Field ◽  
Quasinormal Modes ◽  
De Sitter ◽  
Asymptotically Flat ◽  
Gravitational Perturbations ◽  
Phantom Scalar ◽  
Quantum Interpretation ◽  
The Stability ◽  
Phantom Scalar Field

We investigate the gravitational quasinormal modes (QNMs) for a type of regular black hole (BH) known as phantom BH, which is a static self-gravitating solution of a minimally coupled phantom scalar field with a potential. The studies are carried out for three different spacetimes: asymptotically flat, de Sitter (dS), and anti-de Sitter (AdS). In order to consider the standard odd parity and even parity of gravitational perturbations, the corresponding master equations are derived. The QNMs are discussed by evaluating the temporal evolution of the perturbation field which, in turn, provides direct information on the stability of BH spacetime. It is found that in asymptotically flat, dS, and AdS spacetimes the gravitational perturbations have similar characteristics for both odd and even parities. The decay rate of perturbation is strongly dependent on the scale parameterb, which measures the coupling strength between phantom scalar field and the gravity. Furthermore, through the analysis of Hawking radiation, it is shown that the thermodynamics of such regular phantom BH is also influenced byb. The obtained results might shed some light on the quantum interpretation of QNM perturbation.

scholarly journals Quasinormal modes and their anomalous behavior for black holes in f(R) gravity

2021 ◽  
Vol 81 (5) ◽  
Author(s):  
Almendra Aragón ◽  
P. A. González ◽  
Eleftherios Papantonopoulos ◽  
Yerko Vásquez
Keyword(s):  
Black Hole ◽  
Scalar Field ◽  
Critical Mass ◽  
Quasinormal Modes ◽  
Scalar Fields ◽  
Critical Value ◽  
Anomalous Behavior ◽  
Modified Theories Of Gravity ◽  
De Sitter ◽  
Massive Scalar Field

AbstractWe study the propagation of scalar fields in the background of an asymptotically de Sitter black hole solution in f(R) gravity. The aim of this work is to analyze in modified theories of gravity the existence of an anomalous decay rate of the quasinormal modes (QNMs) of a massive scalar field which was recently reported in Schwarzschild black hole backgrounds, in which the longest-lived modes are the ones with higher angular number, for a scalar field mass smaller than a critical value, while that beyond this value the behavior is inverted. We study the QNMs for various overtone numbers and they depend on a parameter $$\beta $$ β which appears in the metric and characterizes the f(R) gravity. For small $$\beta $$ β , i.e. small deviations from the Schwarzschild–dS black hole the anomalous behavior in the QNMs is present for the photon sphere modes, and the critical value of the mass of the scalar field depends on the parameter $$\beta $$ β while for large $$\beta $$ β , i.e. large deviations, the anomalous behavior and the critical mass does not appear. Also, the critical mass of the scalar field increases when the overtone number increases until the f(R) gravity parameter $$\beta $$ β approaches the near extremal limit at which the critical mass of the scalar field does not depend anymore on the overtone number. The imaginary part of the quasinormal frequencies is always negative leading to a stable propagation of the scalar fields in this background.

scholarly journals Quasinormal modes of massive scalar field with nonminimal coupling in higher-dimensional de Sitter black hole with single rotation

2019 ◽  
Vol 79 (12) ◽  
Author(s):  
Bogeun Gwak
Keyword(s):  
Black Hole ◽  
Scalar Field ◽  
Quasinormal Modes ◽  
Massive Scalar ◽  
Nonminimal Coupling ◽  
De Sitter ◽  
Massive Scalar Field ◽  
Outer Horizon ◽  
Dimensional Spacetime ◽  
Higher Dimensional

AbstractWe analytically investigate the quasinormal modes of the massive scalar field with a nonminimal coupling in the higher-dimensional de Sitter black hole with a single rotation. According to the separated scalar field equation, the boundary conditions of quasinormal modes are well constructed at the outer and cosmological horizons. Then, under near-extremal conditions, where the outer horizon closes to the cosmological horizon, the quasinormal frequencies are obtained and generalized to universal form in the higher-dimensional spacetime. Here, the real part of the frequency includes the scalar field contents, and its imaginary part only depends on the surface gravity at the outer horizon of the black hole.

DECAY OF DIRAC FIELDS IN THE BACKGROUNDS OF DILATONIC BLACK HOLES

2010 ◽  
Vol 25 (08) ◽  
pp. 1713-1723 ◽  
Author(s):  
RAMÓN BECAR ◽  
SAMUEL LEPE ◽  
JOEL SAAVEDRA
Keyword(s):  
Exact Solution ◽  
Black Hole ◽  
Quasinormal Modes ◽  
Dimensional Case ◽  
Two Dimensional ◽  
Asymptotically Flat ◽  
Three Sphere ◽  
Constant Radius ◽  
The Stability ◽  
Dilatonic Black Hole

We find an exact solution to the Dirac equation in the background of the dilatonic black hole in 1 + 1 and 4 + 1 dimensions, and for them we calculate the corresponding quasinormal frequencies. In the two-dimensional case we find that for Weyl spinors the quasinormal modes' (QNM's) frequencies are pure imaginary and have negative sign for all modes, ensuring the stability of the (1 + 1)-dimensional dilatonic black hole. We generalize results to the (4 + 1)-dimensional dilatonic black hole, where the metric is product of a two-dimensional asymptotically flat geometry and a three-sphere with a constant radius. Our conclusion is that the QNMs are pure imaginary, as in the (1 + 1)-dimensional case.

scholarly journals Regular black holes in de Sitter universe: Scalar field perturbations and quasinormal modes

2015 ◽  
Vol 24 (14) ◽  
pp. 1550104 ◽  
Author(s):  
Sharmanthie Fernando
Keyword(s):  
Black Hole ◽  
Scalar Field ◽  
Cosmological Constant ◽  
Quasinormal Modes ◽  
Massless Scalar ◽  
Massless Scalar Field ◽  
De Sitter ◽  
Regular Black Hole ◽  
Text Mode ◽  
De Sitter Universe

The purpose of this paper is to study quasinormal modes (QNMs) of a regular black hole with a cosmological constant due to scalar perturbations. A detailed study of QNMs frequencies for the massless scalar field was done by varying the parameters of the theory such as mass, magnetic charge, cosmological constant and the spherical harmonic index. We have employed the sixth-order WKB approximation to compute the QNMs frequencies. We have also proved analytically that the [Formula: see text] mode for the massless field reaches a constant value at late times. We have approximated the near-extreme regular-de Sitter (dS) black hole potential with the Pöschl–Teller potential to obtain exact frequencies. The null geodesics of the regular-de Sitter black hole is employed to describe the QNMs frequencies at the eikonal limit ([Formula: see text]).

scholarly journals An exact black hole spacetime with scalar field and its shadow together with quasinormal modes

2020 ◽  
Vol 35 (31) ◽  
pp. 2050256 ◽  
Author(s):  
Shuang Yu ◽  
Changjun Gao
Keyword(s):  
Black Hole ◽  
Scalar Field ◽  
Black Hole Solution ◽  
Quasinormal Modes ◽  
The Other ◽  
De Sitter Spacetime ◽  
De Sitter ◽  
First Law Of Thermodynamics ◽  
Sitter Spacetime ◽  
Black Hole Spacetime

We find an exact black hole solution with a minimally coupled scalar field. The corresponding spacetime has two horizons and one of them is the black hole event horizon and the other is the cosmic horizon. In this sense, the solution is analogous to the Schwarzschild-de Sitter (or anti-de Sitter) spacetime. We investigate the thermodynamics and construct the first law of thermodynamics. At the same time, we make a study on the shadow and quasinormal modes of this black hole solution.

scholarly journals Quasinormal modes, stability and shadows of a black hole in the 4D Einstein–Gauss–Bonnet gravity

2020 ◽  
Vol 80 (11) ◽  
Author(s):  
R. A. Konoplya ◽  
A. F. Zinhailo
Keyword(s):  
Black Hole ◽  
Black Hole Solution ◽  
Lorentz Invariance ◽  
Quasinormal Modes ◽  
Dimensional Regularization ◽  
Asymptotically Flat ◽  
Gravitational Perturbations ◽  
Limited Class ◽  
Effective Description ◽  
Naive Approach

AbstractRecently a D-dimensional regularization approach leading to the non-trivial $$(3+1)$$ ( 3 + 1 ) -dimensional Einstein–Gauss–Bonnet (EGB) effective description of gravity was formulated which was claimed to bypass the Lovelock’s theorem and avoid Ostrogradsky instability. Later it was shown that the regularization is possible only for some broad, but limited, class of metrics and Aoki et al. (arXiv:2005.03859) formulated a well-defined four-dimensional EGB theory, which breaks the Lorentz invariance in a theoretically consistent and observationally viable way. The black-hole solution of the first naive approach proved out to be also the exact solution of the well-defined theory. Here we calculate quasinormal modes of scalar, electromagnetic and gravitational perturbations and find the radius of shadow for spherically symmetric and asymptotically flat black holes with Gauss–Bonnet corrections. We show that the black hole is gravitationally stable when ($$-16 M^2<\alpha \lessapprox 0.6 M^2$$ - 16 M 2 < α ⪅ 0.6 M 2 ). The instability in the outer range is the eikonal one and it develops at high multipole numbers. The radius of the shadow $$R_{Sh}$$ R Sh obeys the linear law with a remarkable accuracy.

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