scholarly journals Inside an asymptotically flat hairy black hole

2021 ◽  
Vol 2021 (12) ◽  
Author(s):  
Óscar J. C. Dias ◽  
Gary T. Horowitz ◽  
Jorge E. Santos
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Scalar Field ◽  
Holographic Superconductor ◽  
Charged Scalar ◽  
General Argument ◽  
Asymptotically Flat ◽  
Charged Black Holes ◽  
Scalar Hair ◽  
Hairy Black Hole

Abstract We study the interior of a recently constructed family of asymptotically flat, charged black holes that develop (charged) scalar hair as one increases their charge at fixed mass. Inside the horizon, these black holes resemble the interior of a holographic superconductor. There are analogs of the Josephson oscillations of the scalar field, and the final Kasner singularity depends very sensitively on the black hole parameters near the onset of the instability. In an appendix, we give a general argument that Cauchy horizons cannot exist in a large class of stationary black holes with scalar hair.

scholarly journals Extremal black holes that are not extremal: maximal warm holes

2022 ◽  
Vol 2022 (1) ◽  
Author(s):  
Óscar J. C. Dias ◽  
Gary T. Horowitz ◽  
Jorge E. Santos
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Hawking Temperature ◽  
Charged Scalar ◽  
Asymptotically Flat ◽  
Charged Black Holes ◽  
Maximum Charge ◽  
Scalar Hair ◽  
Hairy Black Hole ◽  
Extremal Black Holes

Abstract We study a family of four-dimensional, asymptotically flat, charged black holes that develop (charged) scalar hair as one increases their charge at fixed mass. Surprisingly, the maximum charge for given mass is a nonsingular hairy black hole with nonzero Hawking temperature. The implications for Hawking evaporation are discussed.

scholarly journals Spinning boson stars and hairy black holes with nonminimal coupling

2018 ◽  
Vol 27 (11) ◽  
pp. 1843009 ◽  
Author(s):  
Carlos A. R. Herdeiro ◽  
Eugen Radu
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Scalar Field ◽  
Coupling Parameter ◽  
Nonminimal Coupling ◽  
Boson Stars ◽  
Hairy Black Holes ◽  
Black Hole Solutions ◽  
Hairy Black Hole ◽  
Coupled Theory

We obtain spinning boson star solutions and hairy black holes with synchronized hair in the Einstein–Klein–Gordon model, wherein the scalar field is massive, complex and with a nonminimal coupling to the Ricci scalar. The existence of these hairy black holes in this model provides yet another manifestation of the universality of the synchronization mechanism to endow spinning black holes with hair. We study the variation of the physical properties of the boson stars and hairy black holes with the coupling parameter between the scalar field and the curvature, showing that they are, qualitatively, identical to those in the minimally coupled case. By discussing the conformal transformation to the Einstein frame, we argue that the solutions herein provide new rotating boson star and hairy black hole solutions in the minimally coupled theory, with a particular potential, and that no spherically symmetric hairy black hole solutions exist in the nonminimally coupled theory, under a condition of conformal regularity.

scholarly journals A new spin on black hole hair

2014 ◽  
Vol 23 (12) ◽  
pp. 1442014 ◽  
Author(s):  
Carlos A. R. Herdeiro ◽  
Eugen Radu
Keyword(s):  
Black Holes ◽  
General Relativity ◽  
Black Hole ◽  
Scalar Field ◽  
Massive Scalar ◽  
Massive Scalar Field ◽  
Hairy Black Holes ◽  
Scalar Hair

We show that scalar hair can be added to rotating, vacuum black holes (BHs) of general relativity. These hairy black holes (HBHs) clarify a lingering question concerning gravitational solitons: Whether a BH can be added at the centre of a boson star (BS), as it typically can for other solitons. We argue that it can, but only if it is spinning. The existence of such HBHs is related to the Kerr superradiant instability triggered by a massive scalar field. This connection leads to the following conjecture: a (hairless) BH, which is afflicted by the superradiant instability of a given field, must allow hairy generalizations with that field.

scholarly journals THE CARDY–VERLINDE FORMULA AND ASYMPTOTICALLY FLAT CHARGED BLACK HOLES

2001 ◽  
Vol 16 (19) ◽  
pp. 1263-1268 ◽  
Author(s):  
DONAM YOUM
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Casimir Effect ◽  
Higher Dimensions ◽  
Thermodynamic Quantities ◽  
Two Dimensional ◽  
Temperature Relation ◽  
Asymptotically Flat ◽  
Charged Black Holes ◽  
Verlinde Formula

We show that the modified Cardy–Verlinde formula without the Casimir effect term is satisfied by asymptotically flat charged black holes in arbitrary dimensions. Thermodynamic quantities of the charged black holes are shown to satisfy the energy-temperature relation of a two-dimensional CFT, which supports the claim in our previous work (Phys. Rev.D61, 044013, hep-th/9910244) that thermodynamics of charged black holes in higher dimensions can be effectively described by two-dimensional theories. We also check the Cardy formula for the two-dimensional black hole compactified from a dilatonic charged black hole in higher dimensions.

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.

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 SCALAR–TENSOR BLACK HOLES COUPLED TO EULER–HEISENBERG NONLINEAR ELECTRODYNAMICS

2007 ◽  
Vol 22 (17) ◽  
pp. 1217-1231 ◽  
Author(s):  
IVAN ZH. STEFANOV ◽  
STOYTCHO S. YAZADJIEV ◽  
MICHAIL D. TODOROV
Keyword(s):  
Black Holes ◽  
Scalar Field ◽  
Numerical Solutions ◽  
Causal Structure ◽  
Nonlinear Electrodynamics ◽  
Massless Scalar ◽  
Massless Scalar Field ◽  
Charged Black Holes ◽  
Maxwell Electrodynamics ◽  
Scalar Hair

The no-scalar-hair conjecture rules out the existence of asymptotically flat black holes with a scalar dressing for a large class of theories. No-scalar-hair theorems have been proved for the cases of neutral black holes and for charged black holes in the Maxwell electrodynamics. These theorems, however, do not apply in the case of nonlinear electrodynamics. In the present work numerical solutions describing charged black holes coupled to Euler–Heisenberg type nonlinear electrodynamics in scalar–tensor theories of gravity with massless scalar field are found. In comparison to the corresponding solution in General Relativity the presented solution has a simpler causal structure the reason for which is the presence of the scalar field. The present class of black holes has a single, nondegenerate horizon, i.e. its causal structure resembles that of the Schwarzschild black hole.

scholarly journals Static and dynamic charged black holes

2019 ◽  
Vol 79 (11) ◽  
Author(s):  
Hyat Huang ◽  
Zhong-Ying Fan ◽  
H. Lü
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Scalar Field ◽  
Reverse Engineering ◽  
Electric Charge ◽  
Scalar Potential ◽  
Hole State ◽  
Minimal Coupling ◽  
Charged Black Holes ◽  
Static Solutions

AbstractWe consider a class of Einstein–Maxwell–dilaton theories in general dimensions and construct both static and dynamic charged black holes. We adopt the reverse engineering procedure and make a specific ansatz for the scalar field and then derive the necessary scalar potential and the non-minimal coupling function between the scalar and the Maxwell field. The resulting static black holes contain mass and electric charge as integration constants. We find that some of the static solutions can be promoted to become dynamical ones in the Eddington–Finkelstein-like coordinates. The collapse solutions describe the evolution from a smaller charged black hole to a larger black hole state, driven by the scalar field.

scholarly journals BRANE WORLD IN A TOPOLOGICAL BLACK HOLES IN ASYMPTOTICALLY FLAT SPACE–TIME

2001 ◽  
Vol 16 (26) ◽  
pp. 1703-1710 ◽  
Author(s):  
DONAM YOUM
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Scalar Field ◽  
Flat Space ◽  
Space Time ◽  
Brane World ◽  
Black Hole Horizon ◽  
World Model ◽  
Asymptotically Flat ◽  
Bulk Scalar Field

We study static brane configurations in the bulk background of the topological black holes in asymptotically flat space–time and find that such configurations are possible even for flat black hole horizon, unlike the AdS black hole case. We construct the brane world model with an orbifold structure S1/Z2 in such bulk background and study massless bulk scalar field.

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