scholarly journals Superradiant stability of five and six-dimensional extremal Reissner–Nordstrom black holes

2021 ◽  
Vol 81 (10) ◽  
Author(s):  
Jia-Hui Huang ◽  
Tian-Tian Cao ◽  
Mu-Zi Zhang
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Numerical Methods ◽  
Effective Potential ◽  
Scalar Perturbation ◽  
Polynomial Equations ◽  
Potential Well ◽  
Massive Scalar ◽  
Higher Dimensional ◽  
The Stability

AbstractWe revisit the superradiant stability of five and six-dimensional extremal Reissner–Nordstrom black holes under charged massive scalar perturbation with a new analytical method. In each case, it is analytically proved that the effective potential experienced by the scalar perturbation has only one maximum outside the black hole horizon and no potential well exists for the superradiance modes. So the five and six-dimensional extremal Reissner–Nordstrom black holes are superradiantly stable. The new method we developed is based on the Descartes’ rule of signs for the polynomial equations. Our result provides a complementary support of previous studies on the stability of higher dimensional extremal Reissner–Nordstrom black holes based on numerical methods.

scholarly journals Analytic study of superradiant stability of Kerr–Newman black holes under charged massive scalar perturbation

2021 ◽  
Vol 81 (5) ◽  
Author(s):  
Jun-Huai Xu ◽  
Zi-Han Zheng ◽  
Ming-Jian Luo ◽  
Jia-Hui Huang
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Effective Potential ◽  
Careful Analysis ◽  
Equation Of Motion ◽  
Analytic Study ◽  
Scalar Perturbation ◽  
Massive Scalar ◽  
Radial Equation ◽  
Newman Black Hole

AbstractThe superradiant stability of a Kerr–Newman black hole and charged massive scalar perturbation is investigated. We treat the black hole as a background geometry and study the equation of motion of the scalar perturbation. From the radial equation of motion, we derive the effective potential experienced by the scalar perturbation. By a careful analysis of this effective potential, it is found that when the inner and outer horizons of Kerr–Newman black hole satisfy $$\frac{r_-}{r_+}\leqslant \frac{1}{3}$$ r - r + ⩽ 1 3 and the charge-to-mass ratios of scalar perturbation and black hole satisfy $$ \frac{q}{\mu }\frac{Q}{ M}>1 $$ q μ Q M > 1 , the Kerr–Newman black hole and scalar perturbation system is superradiantly stable.

scholarly journals Massive scalar perturbations on Myers-Perry–de Sitter black holes with a single rotation

2020 ◽  
Vol 80 (11) ◽  
Author(s):  
Supakchai Ponglertsakul ◽  
Bogeun Gwak
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Quasinormal Modes ◽  
Analytic Formula ◽  
Asymptotic Iteration Method ◽  
Scalar Perturbation ◽  
De Sitter ◽  
Spin Parameter ◽  
Higher Dimensional ◽  
The Stability

AbstractThis study investigates the stability of higher-dimensional singly rotating Myers-Perry–de Sitter (MP–dS) black holes against scalar field perturbations. The phase spaces of MP-dS black holes with one spin parameter are discussed. Additionally, the quasinormal modes (QNMs) of MP-dS black holes are calculated via the asymptotic iteration method and sixth-order Wentzel–Kramers–Brillouin approximation. For near-extremal MP-dS black holes, the event horizon may be considerably close to the cosmological horizon. In such cases, the Pöschl–Teller technique yields an accurate analytic formula for the QNMs. It is found that when the spin parameter of a black hole increases, the scalar perturbation modes oscillate at higher frequencies and decay faster. Furthermore, the MP-dS black hole with a single rotation is found to be stable under perturbation.

scholarly journals Superradiant instability of D-dimensional Reissner–Nordström-anti-de Sitter black hole mirror system

2017 ◽  
Vol 26 (13) ◽  
pp. 1750141 ◽  
Author(s):  
Yang Huang ◽  
Dao-Jun Liu ◽  
Xin-Zhou Li
Keyword(s):  
Black Hole ◽  
Threshold Value ◽  
Scalar Fields ◽  
Scalar Perturbation ◽  
De Sitter ◽  
Charged Scalar ◽  
Dimensional Spacetime ◽  
Higher Dimensional ◽  
The Stability ◽  
Degree Of Instability

In this paper, a detailed analysis for superradiant stability of the system composed by a [Formula: see text]-dimensional Reissner–Nordström-anti-de Sitter (RN-AdS) black hole and a reflecting mirror under charged scalar perturbations are presented in the linear regime. It is found that the stability of the system is heavily affected by the mirror radius as well as the mass of the scalar perturbation, AdS radius and the dimension of spacetime. In a higher dimensional spacetime, the degree of instability of the superradiant modes will be severely weakened. Nevertheless, the degree of instability can be magnified significantly by choosing a suitable value of the mirror radius. Remarkably, when the mirror radius is smaller than a threshold value the system becomes stable. We also find that massive charged scalar fields cannot trigger the instabilities in the background of [Formula: see text]-dimensional asymptotically flat RN black hole. For a given scalar charge, a small RN-AdS black hole can be superradiantly unstable, while a large one may be always stable under charged scalar field with or without a reflecting mirror. We also show that these results can be easily expounded and understood with the help of factorized potential analysis.

scholarly journals A note on the linear stability of black holes in quadratic gravity

2020 ◽  
Vol 135 (11) ◽  
Author(s):  
Christian Dioguardi ◽  
Massimiliano Rinaldi
Keyword(s):  
Black Holes ◽  
General Relativity ◽  
Black Hole ◽  
Special Class ◽  
Einstein Equations ◽  
Kerr Solution ◽  
Scalar Perturbation ◽  
Massive Scalar ◽  
Scale Invariant ◽  
Quadratic Gravity

AbstractBlack holes in f(R)-gravity are known to be unstable, especially the rotating ones. In particular, an instability develops that looks like the classical black hole bomb mechanism: the linearized modified Einstein equations are characterized by an effective mass that acts like a massive scalar perturbation on the Kerr solution in general relativity, which is known to yield instabilities. In this note, we consider a special class of f(R) gravity that has the property of being scale-invariant. As a prototype, we consider the simplest case $$f(R)=R^2$$ f ( R ) = R 2 and show that, in opposition to the general case, static and stationary black holes are stable, at least at the linear level. Finally, the result is generalized to a wider class of f(R) theories.

scholarly journals Analysis of Superradiation Stability of Kerr-Newman Black Hole Using Curve integral

2021 ◽  
Author(s):  
Wen-Xiang Chen
Keyword(s):  
Black Hole ◽  
Event Horizon ◽  
Effective Potential ◽  
Laurent Series ◽  
Potential Well ◽  
Cauchy Integral ◽  
Newman Black Hole

Abstract In this article, a new variable y is added here to expand the results of the above article.We use the properties of the Laurent series and the Cauchy integral. When y is greater than a certain limit, the effective potential of the equation does not have a pole, then there is no potential well outside the event horizon, when p 2(a 2 + Q2)/r2 + < ω < mΩH + qΦH,so the Kerr-Newman black hole is superradiantly stable at that time.

scholarly journals Analysis of Superradiation Stability of Kerr-Newman Black Hole Using Curve integral

2021 ◽  
Author(s):  
Wen-Xiang Chen
Keyword(s):  
Black Hole ◽  
Event Horizon ◽  
Effective Potential ◽  
Laurent Series ◽  
Potential Well ◽  
Cauchy Integral ◽  
Newman Black Hole

Abstract In this article, a new variable y is added here to expand the results of the above article.We use the properties of the Laurent series and the Cauchy integral. When y is greater than a certain limit, the effective potential of the equation does not have a pole, then there is no potential well outside the event horizon, when p 2(a 2 + Q2)/r2 + < ω < mΩH + qΦH,so the Kerr-Newman black hole is superradiantly stable at that time.

scholarly journals Massive scalar field perturbation on Kerr black holes in dynamical Chern–Simons gravity

2021 ◽  
Vol 81 (5) ◽  
Author(s):  
Shao-Jun Zhang
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Scalar Field ◽  
Massive Scalar ◽  
Coupling Constant ◽  
Field Mass ◽  
Field Perturbation ◽  
Massive Scalar Field ◽  
Kerr Black Holes ◽  
Chern Simons

AbstractWe study massive scalar field perturbation on Kerr black holes in dynamical Chern–Simons gravity by performing a $$(2+1)$$ ( 2 + 1 ) -dimensional simulation. Object pictures of the wave dynamics in time domain are obtained. The tachyonic instability is found to always occur for any nonzero black hole spin and any scalar field mass as long as the coupling constant exceeds a critical value. The presence of the mass term suppresses or even quench the instability. The quantitative dependence of the onset of the tachyonic instability on the coupling constant, the scalar field mass and the black hole spin is given numerically.

scholarly journals Instability of charged massive scalar fields in bound states around Kerr–Sen black holes

2015 ◽  
Vol 24 (14) ◽  
pp. 1550102 ◽  
Author(s):  
Haryanto M. Siahaan
Keyword(s):  
Black Holes ◽  
Bound States ◽  
Gordon Equation ◽  
Scalar Fields ◽  
Bound State ◽  
Imaginary Component ◽  
Scalar Perturbation ◽  
Massive Scalar ◽  
Massive Scalar Field ◽  
Klein Gordon

In this paper, we show the instability of a charged massive scalar field in bound states around Kerr–Sen black holes. By matching the near and far region solutions of the radial part in the corresponding Klein–Gordon equation, one can show that the frequency of bound state scalar fields contains an imaginary component which gives rise to an amplification factor for the fields. Hence, the unstable modes for a charged and massive scalar perturbation in Kerr–Sen background can be shown.

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 BLACK-HOLE BOMBS AT THE LHC

2012 ◽  
Vol 27 (07) ◽  
pp. 1250038 ◽  
Author(s):  
JONG-PHIL LEE
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Rotating Black Hole ◽  
Field Amplification ◽  
Higher Dimensional ◽  
Original Field

A particle scattered off by a rotating black hole can be amplified when the system is in the superradiant regime. If the system is surrounded by a mirror which reflects the particle back to the black hole the whole system forms a black-hole bomb, amplifying the original field exponentially. We show in this paper that higher-dimensional black holes can also form black-hole bombs at the LHC. For a pion the e-folding time for the field amplification is tc ~ 10-23–10-24 sec . If the lifetime of the black hole is long enough compared with tc, we can observe severely amplified fields.

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