scholarly journals Quasinormal modes of a black hole with a cloud of strings in Einstein–Gauss–Bonnet gravity

2017 ◽  
Vol 26 (10) ◽  
pp. 1750113 ◽  
Author(s):  
J. P. Morais Graça ◽  
Godonou I. Salako ◽  
Valdir B. Bezerra
Keyword(s):  
General Relativity ◽  
Black Hole ◽  
Scalar Field ◽  
Quasinormal Modes ◽  
Wkb Approximation ◽  
Bonnet Gravity

The quasinormal modes for a scalar field in the background spacetime corresponding to a black hole, with a cloud of strings, in Einstein–Gauss–Bonnet gravity, and the tensor quasinormal modes corresponding to perturbations in such spacetime, were both calculated using the WKB approximation. In the obtained results, we emphasize the role played by the parameter associated with the string cloud, comparing them with the results already obtained for the Boulware–Deser metric. We also study how the Gauss–Bonnet correction to general relativity affects the results for the quasinormal modes, comparing them with the same background in general relativity.

scholarly journals Scalar modes, spontaneous scalarization and circular null-geodesics of black holes in scalar-Gauss–Bonnet gravity

2020 ◽  
Vol 29 (11) ◽  
pp. 2041006 ◽  
Author(s):  
Caio F. B. Macedo
Keyword(s):  
Black Holes ◽  
General Relativity ◽  
Black Hole ◽  
Scalar Field ◽  
Quasinormal Modes ◽  
Mode Analysis ◽  
Bonnet Gravity ◽  
Black Hole Binaries ◽  
The Impact ◽  
Black Hole Solutions

In general relativity, astrophysical black holes (BHs) are simple objects, described by just their mass and spin. These simple solutions are not exclusive to general relativity, as they also appear in theories that allow for an extra scalar degree of freedom. Recently, it was shown that some theories which couple a scalar field with the Gauss–Bonnet invariant can have the same classic black hole solutions from general relativity as well as hairy BHs. These scalarized solutions can be stable, having an additional “charge” term that has an impact on the gravitational-wave emission by black hole binaries. In this paper, we overview black hole solutions in scalar-Gauss–Bonnet gravity, considering self-interacting terms for the scalar field. We present the mode analysis for the monopolar and dipolar perturbations around the Schwarzschild black hole in scalar-Gauss–Bonnet, showing the transition between stable and unstable solutions. We also present the time-evolution of scalar Gaussian wave packets, analyzing the impact of the scalar-Gauss–Bonnet term in their evolution. We then present some scalarized solutions, showing that nonlinear coupling functions and self-interacting terms can stabilize them. Finally, we compute the light-ring frequency and the Lyapunov exponent, which possibly estimate the black hole quasinormal modes in the eikonal limit.

Extended GUP corrected thermodynamics, shadow radius and quasinormal modes of charged AdS black holes in Gauss–Bonnet gravity

2021 ◽  
pp. 2150137
Author(s):  
Shahid Chaudhary ◽  
Abdul Jawad ◽  
Kimet Jusufi ◽  
Muhammad Yasir
Keyword(s):  
Black Hole ◽  
Generalized Uncertainty Principle ◽  
Quasinormal Modes ◽  
Nonlinear Electrodynamics ◽  
Horizon Radius ◽  
Bonnet Gravity ◽  
Ads Black Holes ◽  
Dimensional Black Hole ◽  
Relationship Of ◽  
The Relationship

This paper explores the influence of special type of higher order generalized uncertainty principle on the thermodynamics of five-dimensional black hole in Einstein–Gauss–Bonnet gravity coupled to nonlinear electrodynamics. We examine the corrected thermodynamical properties of the black hole with some interesting limiting cases [Formula: see text] and [Formula: see text] and compared our results with usual thermodynamical relations. We observe that the influence of GUP correction stabilizes the BH and BH solution remains physical throughout the region of horizon radius. In this framework, we also uncover the relationship of shadow radius and quasinormal modes of the mentioned black hole. We conclude that shadow radius of our considered black hole is a perfect circle and it decreases with increasing values of charge and Gauss–Bonnet parameter. We also verify the inverse relation between the quasinormal modes frequencies and shadow radius, i.e. quasinormal modes should increase with increasing values of Gauss–Bonnet parameter and electric charge.

ASYMPTOTIC QUASINORMAL MODES IN EINSTEIN–GAUSS–BONNET GRAVITY

2011 ◽  
Vol 26 (16) ◽  
pp. 2783-2794 ◽  
Author(s):  
J. SADEGHI ◽  
A. BANIJAMALI ◽  
M. R. SETARE ◽  
H. VAEZ
Keyword(s):  
Scalar Field ◽  
Effective Potential ◽  
Quasinormal Modes ◽  
Space Time ◽  
Massive Scalar ◽  
Massive Scalar Field ◽  
Momentum Vector ◽  
Five Dimensions ◽  
Bonnet Gravity ◽  
Temperature Scalar

In this paper we consider a massive scalar field on the boundary of AdS space–time and calculate the quasinormal modes for the string inspired Einstein–Gauss–Bonnet gravity in five dimensions. We study the effects of Gauss–Bonnet parameter, temperature, scalar field's mass and momentum vector on the effective potential and quasinormal modes.

Disappearance of Black Hole Criticality in Semiclassical General Relativity

1997 ◽  
Vol 12 (10) ◽  
pp. 709-718 ◽  
Author(s):  
Takeshi Chiba ◽  
Masaru Siino
Keyword(s):  
General Relativity ◽  
Black Hole ◽  
Scalar Field ◽  
Critical Phenomena ◽  
Equations Of Motion ◽  
Quantum Effects ◽  
Hole Formation ◽  
Trace Anomaly ◽  
Self Similar ◽  
Similar Solutions

We investigate the quantum effects on the so-called critical phenomena in black hole formation. Quantum effects of a scalar field are treated semiclassically via a trace anomaly method. It is found that the demand of regularity at the origin implies the disappearance of the echo. It is also found that semiclassical equations of motion do not admit continuously self-similar solutions. The quantum effects would change the critical solution from a discretely self-similar one to a solution without critical phenomena.

scholarly journals Massive scalar field quasinormal modes of a Schwarzschild black hole surrounded by quintessence

Open Physics ◽  
2008 ◽  
Vol 6 (2) ◽  
Author(s):  
Chunrui Ma ◽  
Yuanxing Gui ◽  
Wei Wang ◽  
Fujun Wang
Keyword(s):  
Black Hole ◽  
Scalar Field ◽  
Quasinormal Modes ◽  
Massless Scalar ◽  
Massless Scalar Field ◽  
Massive Scalar ◽  
Schwarzschild Black Hole ◽  
Third Order ◽  
Massive Scalar Field ◽  
Absolute Value

AbstractWe present the quasinormal frequencies of the massive scalar field in the background of a Schwarzchild black hole surrounded by quintessence with the third-order WKB method. The mass of the scalar field u plays an important role in studying the quasinormal frequencies, the real part of the frequencies increases linearly as mass of the field u increases, while the imaginary part in absolute value decreases linearly which leads to damping more slowly than the massless scalar field. The frequencies have a limited value, so it is easier to detect the quasinormal modes. Moreover, owing to the presence of the quintessence, the massive scalar field damps more slowly.

scholarly journals An exploration of the black hole entropy in Gauss–Bonnet gravity via the Weyl tensor

2021 ◽  
pp. 2150193
Author(s):  
Taha A. Malik ◽  
Rafael Lopez-Mobilia
Keyword(s):  
General Relativity ◽  
Black Hole ◽  
Weyl Tensor ◽  
Black Hole Entropy ◽  
Entropy Density ◽  
Modified Theories Of Gravity ◽  
Bonnet Gravity ◽  
Gravitational Entropy ◽  
Theories Of Gravity ◽  
Almost All

Various proposals for gravitational entropy densities have been constructed from the Weyl tensor. In almost all cases, though, these studies have been restricted to general relativity, and little has been done in modified theories of gravity. However, in this paper, we investigate the simplest proposal for an entropy density constructed from the Weyl tensor in five-dimensional Gauss–Bonnet gravity and find that it fails to reproduce the expected entropy of a black hole.

Area spectrum from quasinormal modes of a Lifshitz black hole in 2+1 dimensions

2015 ◽  
Vol 30 (13) ◽  
pp. 1550078 ◽  
Author(s):  
Sharmanthie Fernando
Keyword(s):  
Black Hole ◽  
Mass Spectrum ◽  
Scalar Field ◽  
Quasinormal Modes ◽  
Area Spectrum ◽  
Conformal Gravity ◽  
Btz Black Hole ◽  
The Future ◽  
Lifshitz Black Hole

In this paper, we have studied the area and mass spectrum of a Lifshitz black hole in 2+1 dimensions. This black hole is obtained for conformal gravity in 2+1 dimensions and is asymptotic to z = 0 Lifshitz spacetime. Quasinormal modes (QNM) frequencies of the conformally coupled scalar field perturbations are employed for the purpose of analyzing the area spectrum of the black hole. We have used two methods: modified Hod's conjecture and Kunsttater's method. In both methods, the area and the mass spectrum is shown to be equally spaced. We compared our results with the area spectrum of the BTZ black hole and the z = 3 black hole and made suggestions to extend this work in the future.

scholarly journals DECAY OF SPIN-1/2 FIELD AROUND REISSNER–NORDSTROM BLACK HOLE

2004 ◽  
Vol 13 (06) ◽  
pp. 1105-1118 ◽  
Author(s):  
WEI ZHOU ◽  
JIAN-YANG ZHU
Keyword(s):  
Black Hole ◽  
Scalar Field ◽  
Quantum Number ◽  
Turning Point ◽  
Quasinormal Modes ◽  
Astronomical Observation ◽  
Dirac Field ◽  
Neutrino Field ◽  
Extremal Limit ◽  
Field Decay

To find what influence the charge of the black hole Q will bring to the evolution of the quasinormal modes, we calculate the quasinormal frequencies of the neutrino field (charge e=0) perturbations and those of the massless Dirac field (e≠0) perturbations in the RN metric. The influences of Q, e, the momentum quantum number l, and the mode number n are discussed. Among the conclusions, the most important one is that, at the stage of quasinormal ringing, when the black hole and the field have the same kind of charge (eQ>0), the quasinormal modes of the massless charged Dirac field decay faster than those of the neutral ones, and when eQ<0, the massless charged Dirac field decays slower, which may be helpful in the astronomical observation. In addition, we compare the influence from the charge of the black hole to the spin 1/2 field and scalar field perturbations including the extremal limit (M=Q) and find a turning point of Q exists in both cases. The explanation of this fact is unclear with some suggestions that may be helpful are given.

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