scholarly journals Decay of a charged scalar field around a black hole: Quasinormal modes of RN, RNAdS, and dilaton black holes

2002 ◽  
Vol 66 (8) ◽  
Author(s):  
R. A. Konoplya
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Scalar Field ◽  
Quasinormal Modes ◽  
Charged Scalar ◽  
Charged Scalar Field ◽  
Dilaton Black Holes

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 ABSORPTION CROSS SECTION OF A RN BLACK HOLE

2009 ◽  
Vol 18 (01) ◽  
pp. 1-11 ◽  
Author(s):  
R. SINI ◽  
V. C. KURIAKOSE
Keyword(s):  
Black Hole ◽  
Scalar Field ◽  
Event Horizon ◽  
Cross Section ◽  
Absorption Cross Section ◽  
Hawking Temperature ◽  
Absorption Cross ◽  
Charged Scalar ◽  
Matter Waves ◽  
Charged Scalar Field

The behavior of a charged scalar field in the RN black hole space–time is studied using the WKB approximation. In the present work, it is assumed that matter waves can be reflected from the event horizon. Using this effect, the Hawking temperature and the absorption cross section for an RN black hole placed in a charged scalar field are calculated. The absorption cross section σabs is found to be inversely proportional to the square of the Hawking temperature of the black hole.

scholarly journals CFT dual of charged AdS black hole in the large dimension limit

2016 ◽  
Vol 25 (07) ◽  
pp. 1650085 ◽  
Author(s):  
Er-Dong Guo ◽  
Miao Li ◽  
Jia-Rui Sun
Keyword(s):  
Black Hole ◽  
Scalar Field ◽  
Cross Sections ◽  
Central Charge ◽  
Conformal Symmetry ◽  
Large Dimension ◽  
Absorption Cross ◽  
De Sitter ◽  
Charged Scalar ◽  
Charged Scalar Field

We study the dual CFT description of the [Formula: see text]-dimensional Reissner–Nordström-Anti de Sitter (RN-AdS[Formula: see text]) black hole in the large dimension (large [Formula: see text]) limit, both for the extremal and nonextremal cases. The central charge of the dual CFT2 (or chiral CFT1) is calculated for the near-horizon near extremal geometry which possesses an AdS2 structure. Besides, the [Formula: see text]-picture hidden conformal symmetry in the nonextremal background can be naturally obtained by a probe charged scalar field in the large [Formula: see text] limit, without the need to input the usual limits to probe the hidden conformal symmetry. Furthermore, a new dual CFT description of the nonextremal RN-AdS[Formula: see text] black hole is found in the large [Formula: see text] limit and the duality is analyzed by comparing the entropies, the absorption cross-sections and the retarded Green’s functions obtained both from the gravity and the dual CFT sides.

scholarly journals Boson stars and solitons confined in a Minkowski box

2021 ◽  
Vol 2021 (4) ◽  
Author(s):  
Oscar J. C. Dias ◽  
Ramon Masachs ◽  
Paul Rodgers
Keyword(s):  
Black Hole ◽  
Scalar Field ◽  
Ground State ◽  
Normal Modes ◽  
Junction Conditions ◽  
Mass Limit ◽  
Boson Stars ◽  
Charged Scalar ◽  
Charged Scalar Field ◽  
Scalar Hair

Abstract We consider the static charged black hole bomb system, originally designed for a (uncharged) rotating superradiant system by Press and Teukolsky. A charged scalar field confined in a Minkowski cavity with a Maxwell gauge field has a quantized spectrum of normal modes that can fit inside the box. Back-reacting non-linearly these normal modes, we find the hairy solitons, a.k.a boson stars (depending on the chosen U(1) gauge), of the theory. The scalar condensate is totally confined inside the box and, outside it, we have the Reissner-Nordström solution. The Israel junction conditions at the box surface layer determine the stress tensor that the box must have to confine the scalar hair. Some of these horizonless hairy solutions exist for any value of the scalar field charge and not only above the natural critical charges of the theory (namely, the critical charges for the onset of the near-horizon and superradiant instabilities of the Reissner-Nordström black hole). However, the ground state solutions have a non-trivial intricate phase diagram with a main and a secondary family of solitons (some with a Chandrasekhar mass limit but others without) and there are a third and a fourth critical scalar field charges where the soliton spectra changes radically. Most of these intricate properties are not captured by a higher order perturbative analysis of the problem where we simply back-react a normal mode of the system.

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