scholarly journals Superradiant instability of charged scalar fields in higher-dimensional Reissner-Nordström-de Sitter black holes

2019 ◽  
Vol 100 (4) ◽  
Author(s):  
Kyriakos Destounis
2017 ◽  
Vol 26 (13) ◽  
pp. 1750141 ◽  
Author(s):  
Yang Huang ◽  
Dao-Jun Liu ◽  
Xin-Zhou Li

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.


2002 ◽  
Vol 17 (20) ◽  
pp. 2747-2747
Author(s):  
A. BEESHAM

The singularity theorems of general relativity predict that gravitational collapse finally ends up in a spacetime singularity1. The cosmic censorship hypothesis (CCH) states that such a singularity is covered by an event horizon2. Despite much effort, there is no rigorous formulation or proof of the CCH. In view of this, examples that appear to violate the CCH and lead to naked singularities, in which non-spacelike curves can emerge, rather than black holes, are important to shed more light on the issue. We have studied several collapse scenarios which can lead to both situations3. In the case of the Vaidya-de Sitter spacetime4, we have shown that the naked singularities that arise are of the strong curvature type. Both types of singularities can also arise in higher dimensional Vaidya and Tolman-Bondi spacetimes, but black holes are favoured in some sense by the higher dimensions. The charged Vaidya-de Sitter spacetime also exhibits both types of singularities5.


2006 ◽  
Vol 24 (3) ◽  
pp. 625-644 ◽  
Author(s):  
Abhay Ashtekar ◽  
Tomasz Pawlowski ◽  
Chris Van Den Broeck

2019 ◽  
Vol 28 (03) ◽  
pp. 1950049 ◽  
Author(s):  
Kai Lin ◽  
Fei-Hung Ho ◽  
Wei-Liang Qian

In this work, we investigate the [Formula: see text]-dimensional charged static black hole solutions in the Einstein-æther theory. By taking the metric parameter [Formula: see text] to be [Formula: see text], and [Formula: see text], we obtain the spherical, planar, and hyperbolic spacetimes, respectively. Three choices of the cosmological constant, [Formula: see text], [Formula: see text] and [Formula: see text], are investigated, which correspond to asymptotically de Sitter, flat and anti-de Sitter spacetimes. The obtained results show the existence of the universal horizon in higher dimensional cases which may trap any particle with arbitrarily large velocity. We analyze the horizon and the surface gravity of four- and five-dimensional black holes, and the relations between the above quantities and the electrical charge. It is shown that when the aether coefficient [Formula: see text] or the charge [Formula: see text] increases, the outer Killing horizon shrinks and approaches the universal horizon. Furthermore, the surface gravity decreases and approaches zero in the limit [Formula: see text] or [Formula: see text], where [Formula: see text] is the extreme charge. The main features of the horizon and surface gravity are found to be similar to those in [Formula: see text] case, but subtle differences are also observed.


Author(s):  
Almendra Aragón ◽  
Ramón Bécar ◽  
P. A. González ◽  
Yerko Vásquez

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.


2015 ◽  
Vol 24 (06) ◽  
pp. 1550040 ◽  
Author(s):  
Seyed Hossein Hendi

In this paper, we consider third-order Lovelock–Maxwell gravity with additional (Fμν Fμν)2 term as a nonlinearity correction of the Maxwell theory. We obtain black hole solutions with various horizon topologies (and various number of horizons) in which their asymptotical behavior can be flat or anti-de Sitter with an effective cosmological constant. We investigate the effects of Lovelock and electrodynamic corrections on properties of the solutions. Then, we restrict ourselves to asymptotically flat solutions and calculate the conserved and thermodynamic quantities. We check the first law of thermodynamics for these black hole solutions and calculate the heat capacity to analyze stability. Although higher dimensional black holes in Einstein gravity are unstable, here we look for suitable constraints on the black hole radius to find thermally stable black hole solutions.


2014 ◽  
Vol 90 (6) ◽  
Author(s):  
Hui-Hua Zhao ◽  
Li-Chun Zhang ◽  
Meng-Sen Ma ◽  
Ren Zhao

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