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.

QUANTIZATION OF ENTROPY SPECTRA OF BLACK HOLES

2013 ◽  
Vol 22 (02) ◽  
pp. 1330001 ◽  
Author(s):  
YONGJOON KWON ◽  
SOONKEON NAM
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Correspondence Principle ◽  
Scattering Problem ◽  
Classical System ◽  
Quasinormal Modes ◽  
Entropy Spectrum ◽  
Total Transmission ◽  
Transmission Modes ◽  
Characteristic Modes

From the quasinormal modes (QNM) of black holes, we obtain the quantizations of the entropy and horizon area of black holes via Bohr–Sommerfeld quantization, based on Bohr's correspondence principle. For this, we identify the appropriate action variable of the classical system corresponding to a black hole. By considering the BTZ black holes in topologically massive gravity as well as Einstein gravity, it is found that the spectra of not the horizon areas but the entropies of black holes are equally spaced. We also propose that other characteristic modes of black holes, which are non-QNM or holographic QNM, can be used in quantization of entropy spectra just like QNM. From these modes, it is found that only the entropy spectrum of the warped AdS3 black hole is equally spaced as well. Furthermore, by considering a scattering problem in a black hole, we propose that the total transmission modes and total reflection modes of black holes can be regarded as characteristic modes of black holes and result in the equally spaced entropy of the Kerr and Reissner–Nordström black holes. Finally, we conclude that there is a universal behavior that the entropy spectra of various black holes are equally spaced.

Universality of spectra of black holes

2014 ◽  
Vol 29 (36) ◽  
pp. 1450191 ◽  
Author(s):  
Xiao-Xiong Zeng ◽  
Qiang Li ◽  
Yi-Wen Han
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Area Spectrum ◽  
Spherically Symmetric ◽  
Action Variable ◽  
Intrinsic Properties ◽  
Entropy Spectrum ◽  
Symmetric Black Hole

Using exclusively an action variable, we quantize a static, spherically symmetric black hole. The spacings of the quantized entropy spectrum and area spectrum are found to be equal to the values given by Bekenstein. Interestingly, we find the spectra are independent of the hairs of the black holes and the mode of motion of a particle outside the spacetime, which depends only on the intrinsic properties of the gravity. Our result shows that the spectra are universal provided the spacetime owns a horizon.

SPECTROSCOPY OF ROTATING BLACK HOLES VIA AN ACTION INVARIANCE

2012 ◽  
Vol 27 (24) ◽  
pp. 1250139 ◽  
Author(s):  
CHENG-ZHOU LIU
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Quasinormal Modes ◽  
Entropy Spectrum ◽  
Quantization Rule ◽  
Rotating Black Holes

The spectroscopy of rotating black holes are investigated via an action invariance of black holes. Without using the quasinormal modes of black holes, the area and entropy spectrum for Kerr and Kerr–Newman black holes are calculated, respectively. For these rotating black holes, the same result of the equally spaced area and entropy spectrum is derived by utilizing the action invariance and with the help of Bohr–Sommerfield quantization rule. The present black hole spectroscopy is consistent not only to the result of other researches by the action invariance but also the original Bekenstein's spectra.

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 Entropy spectrum of the apparent horizon of Vaidya black holes via adiabatic invariance

2016 ◽  
Vol 31 (06) ◽  
pp. 1650011 ◽  
Author(s):  
Ge-Rui Chen ◽  
Yong-Chang Huang
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Apparent Horizon ◽  
Generic Property ◽  
Entropy Spectrum ◽  
Adiabatic Invariance ◽  
Hawking Effect ◽  
The One

The spectroscopy of the apparent horizon of Vaidya black holes is investigated via adiabatic invariance. We obtain an equally spaced entropy spectrum with its quantum equal to the one given by Bekenstein [J. D. Bekenstein, Phys. Rev. D 7, 2333 (1973)]. We demonstrate that the quantization of entropy and area is a generic property of horizon, not only for stationary black holes, and the results also exit in a dynamical black hole. Our work also shows that the quantization of black hole is closely related to the tunneling formalism for deriving the Hawking effect, which is interesting.

scholarly journals Weak Gravitational Lensing by Bocharova-Bronnikove-Melnikov-Bekenstein Black Holes Using Gauss-Bonnet Theorem

2020 ◽  
Author(s):  
Wajiha Javed ◽  
Muhammad Bilal Khadim ◽  
Ali Övgün
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Gravitational Lensing ◽  
Deflection Angle ◽  
Spherically Symmetric ◽  
Plasma Medium ◽  
Weak Gravitational Lensing ◽  
The Deflection Angle ◽  
Bonnet Theorem ◽  
Symmetric Spacetime

In this article, we demonstrate the weak gravitational lensing in the context of Bocharova-Bronnikove-Melnikov-Bekenstein (BBMB) black hole. To this desire, we derive the deflection angle of light in a plasma medium by BBMB black hole using the Gibbons and Werner method. First, we obtain the Gaussian optical curvature and implement the Gauss-Bonnet theorem to investigate the deflection angle for spherically symmetric spacetime of BBMB black hole. Moreover, we also analyze the graphical behavior of deflection angle by BBMB black hole in the presence of plasma medium.

scholarly journals New Model of 4D Einstein–Gauss–Bonnet Gravity Coupled with Nonlinear Electrodynamics

Universe ◽  
2021 ◽  
Vol 7 (7) ◽  
pp. 249
Author(s):  
Sergey Il’ich Kruglov
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Symmetric Solution ◽  
Emission Rate ◽  
Quasinormal Modes ◽  
Black Hole Thermodynamics ◽  
Nonlinear Electrodynamics ◽  
Spherically Symmetric ◽  
Bonnet Gravity ◽  
Spherically Symmetric Solution

New spherically symmetric solution in 4D Einstein–Gauss–Bonnet gravity coupled with nonlinear electrodynamics is obtained. At infinity, this solution has the Reissner–Nordström behavior of the charged black hole. The black hole thermodynamics, entropy, shadow, energy emission rate, and quasinormal modes of black holes are investigated.

scholarly journals LUKEWARM BLACK HOLES IN QUADRATIC GRAVITY

2011 ◽  
Vol 26 (14) ◽  
pp. 999-1007 ◽  
Author(s):  
JERZY MATYJASEK ◽  
KATARZYNA ZWIERZCHOWSKA
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Event Horizon ◽  
Fourth Order ◽  
Spherically Symmetric ◽  
Cosmological Horizon ◽  
De Sitter ◽  
Quadratic Gravity ◽  
De Sitter Universe ◽  
Electrically Charged

Perturbative solutions to the fourth-order gravity describing spherically-symmetric, static and electrically charged black hole in an asymptotically de Sitter universe is constructed and discussed. Special emphasis is put on the lukewarm configurations, in which the temperature of the event horizon equals the temperature of the cosmological horizon.

Accretion onto a Black Hole

2014 ◽  
Author(s):  
Charles D. Bailyn
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Potential Energy ◽  
Gravitational Potential ◽  
Gas Flow ◽  
Gravitational Potential Energy ◽  
Spherically Symmetric ◽  
Potential Well ◽  
Accretion Flows ◽  
Flow Geometry

This chapter explores the ways that accretion onto a black hole produces energy and radiation. As material falls into a gravitational potential well, energy is transformed from gravitational potential energy into other forms of energy, so that total energy is conserved. Observing such accretion energy is one of the primary ways that astrophysicists pinpoint the locations of potential black holes. The spectrum and intensity of this radiation is governed by the geometry of the gas flow, the mass infall rate, and the mass of the accretor. The simplest flow geometry is that of a stationary object accreting mass equally from all directions. Such spherically symmetric accretion is referred to as Bondi-Hoyle accretion. However, accretion flows onto black holes are not thought to be spherically symmetric—the infall is much more frequently in the form of a flattened disk.

scholarly journals Deforming charged black holes with dipolar differential rotation boundary

2020 ◽  
Vol 80 (7) ◽  
Author(s):  
Tong-Tong Hu ◽  
Shuo Sun ◽  
Hong-Bo Li ◽  
Yong-Qiang Wang
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Chemical Potential ◽  
Dimensional Space ◽  
Quasinormal Modes ◽  
Fixed Temperature ◽  
First Case ◽  
Ads Black Holes ◽  
Horizon Geometry ◽  
Black Hole Solutions

Abstract Motivated by the recent studies of the novel asymptotically global $$\hbox {AdS}_4$$AdS4 black hole with deformed horizon, we consider the action of Einstein–Maxwell gravity in AdS spacetime and construct the charged deforming AdS black holes with differential boundary. In contrast to deforming black hole without charge, there exists at least one value of horizon for an arbitrary temperature. The extremum of temperature is determined by charge q and divides the range of temperature into several parts. Moreover, we use an isometric embedding in the three-dimensional space to investigate the horizon geometry. The entropy and quasinormal modes of deforming charged AdS black hole are also studied in this paper. Due to the existence of charge q, the phase diagram of entropy is more complicated. We consider two cases of solutions: (1) fixing the chemical potential $$\mu $$μ; (2) changing the value of $$\mu $$μ according to the values of horizon radius and charge. In the first case, it is interesting to find there exist two families of black hole solutions with different horizon radii for a fixed temperature, but these two black holes have same horizon geometry and entropy. The second case ensures that deforming charged AdS black hole solutions can reduce to standard RN–AdS black holes.

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