O "bom professor": entre o possível e o necessário

Dias, Gabriela Bernardes Makishi

doi:10.11606/d.48.2015.tde-19102015-103755

Cited by 12 publications

(20 citation statements)

References 4 publications

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“…(13) will be reduced to unity in the fluxes by the normalization condition: Θ 2 (θ)dΩ = 1. In addition, the solution of the θ-directional equation has been treated and discussed in various studies [48,[56][57][58][59][60][61][62][63][64][65][66] (see also references therein). In several limits, we can expect the form of Θ(θ).…”

Section: Solution To Scalar Field Equationmentioning

confidence: 99%

“…These radiations are not in equilibrium, which is directly related to the stability of the dS black hole, and a proper temperature should be set [56]. Although the propagation of a scalar field in (A)dS black holes is complex, various analytical studies have investigated (A)dS black holes [48,[57][58][59][60][61][62][63][64][65][66]. In particular, the scalar field non-minimally coupled with gravity has recently been studied in dS black holes [53][54][55][56]67] because such a scalar field acts differently in a low-frequency mode compared with the case of minimal coupling.…”

Section: Introductionmentioning

confidence: 99%

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Weak cosmic censorship conjecture in Kerr-(anti-)de Sitter black hole with scalar field

Gwak

2018

J. High Energ. Phys.

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We investigate the weak cosmic censorship conjecture in Kerr-(anti-)de Sitter black holes under the scattering of a scalar field. We test the conjecture in terms of whether the black hole can exceed the extremal condition with respect to its change caused by the energy and angular momentum fluxes of the scalar field. Without imposing the laws of thermodynamics, we prove that the conjecture is valid in all the initial states of the black hole (non-extremal, near-extremal, and extremal black holes). The validity in the case of the near-extremal black hole is different from the results of similar tests conducted by adding a particle because the fluxes represent the energy and angular momentum transferred to the black hole during the time interval not included in the tests involving the particle. Using the time interval, we show that the angular velocity of the black hole with the scalar field of a constant state takes a long time for saturation to the frequency of the scalar field. 1 rasenis@sejong.ac.krBlack holes, which are directly proven to exist through detection by the Laser Interferometer Gravitational-Wave Observatory (LIGO), are among the most interesting topics in gravity theories. Classically, in the black hole spacetime, there is an event horizon through which no matter can escape from the black hole; thus, no radiation from the black hole can reach an observer located outside this horizon. However, in quantum theory, black holes act as thermal systems that emit energy through Hawking radiation [1,2]. In Hawking radiation, the Hawking temperature is defined for a black hole. Furthermore, when a particle is added to the black hole, depending on the conserved quantities of the particle, the conserved quantities of the black hole, such as mass and angular momentum, can increase or decrease. However, an irreducible quantity exists during this process, which is known as the irreducible mass [3][4][5]. The irreducible mass is the energy distributed on the surface of the horizon of the black hole [6]. Owing to the similarity between the irreducible mass and the thermodynamic entropy, the Bekenstein-Hawking entropy is defined to be proportional to the surface area of the black hole, which is the square of its irreducible mass [7,8]. Accordingly, we can establish the laws of thermodynamics for black holes.

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Section: Solution To Scalar Field Equationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Weak cosmic censorship conjecture in Kerr-(anti-)de Sitter black hole with scalar field

Gwak

2018

J. High Energ. Phys.

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“…In order to solve the resulting equations of motion we use a standard Newton-Raphson relaxation routine on a single Chebyshev grid 3 and provide detailed convergence tests in the Appendix C. For more details on the numerical implementation see for instance [31].…”

Section: The Actionmentioning

confidence: 99%

Evidence for the existence of a novel class of supersymmetric black holes with AdS ₅ ×S ⁵ asymptotics

Markeviciute

Santos

2018

Class. Quantum Grav.

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We construct a new class of charged, rotating hairy black holes in a consistent truncation of N = 8 supergravity, which retains one charged scalar field and a U(1) gauge field. These hairy solutions can be uplifted to solutions of type IIB supergravity with AdS 5 ×S 5 asymptotics. We find rotating hairy black holes with finite entropy arbitrarily close to the supersymmetric bound -the resulting supersymmetric solution is a one-parameter extension of the Gutowski-Reall solution. These solutions have finite curvature invariants (including at extremality), but in the extremal limit exhibit diverging tidal forces in the near horizon region. Nevertheless, we argue that these limiting supersymmetric black holes can be consistently studied within the supergravity approximation.

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“…Indeed, it would be convenient, putting the metric in the Gaussian form (2), e.g., to evaluate the mass and angular momenta [42] for rotating black holes from Eqs. (12), (13). However, in the next section it is argued that, for the purpose of vacuum energy computation it is enough to consider just the deformation induced by the rotation parameters on the global AdS spacetime, i.e., the line element (26).…”

Section: Kerr Black Hole Metric In Odd Spacetime Dimensionsmentioning

confidence: 99%

“…[12,13]. Perturbations of the black hole metric are equivalent to the perturbation of a thermal state on the boundary CFT.…”

Section: Introductionmentioning

confidence: 99%

Vacuum energy in Kerr-AdS black holes

Olavarria

Olea

2014

Phys. Rev. D

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We compute the vacuum energy for Kerr black holes with anti-de Sitter (AdS) asymptotics in dimensions 5 ≤ D ≤ 9 with all rotation parameters. The calculations are carried out employing an alternative regularization scheme for asymptotically AdS gravity, which considers supplementing the bulk action with counterterms which are a given polynomial in the extrinsic and intrinsic curvatures of the boundary (also known as Kounterterms). The Kerr-Schild form of the rotating solutions enables us to identify the vacuum energy as coming from the part of the metric that corresponds to a global AdS spacetime written in oblate spheroidal coordinates. We find that the zero-point energy for higher-dimensional Kerr-AdS reduces to one of a Schwarzschild-AdS black hole when all the rotation parameters are equal to each other, a fact that is well known in five dimensions. We also sketch a compact expression for the vacuum energy formula in terms of asymptotic quantities that might be useful to extend the computations to higher odd dimensions.

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O "bom professor": entre o possível e o necessário

Cited by 12 publications

References 4 publications

Weak cosmic censorship conjecture in Kerr-(anti-)de Sitter black hole with scalar field

Weak cosmic censorship conjecture in Kerr-(anti-)de Sitter black hole with scalar field

Evidence for the existence of a novel class of supersymmetric black holes with AdS ₅ ×S ⁵ asymptotics

Vacuum energy in Kerr-AdS black holes

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O "bom professor": entre o possível e o necessário

Cited by 12 publications

References 4 publications

Weak cosmic censorship conjecture in Kerr-(anti-)de Sitter black hole with scalar field

Weak cosmic censorship conjecture in Kerr-(anti-)de Sitter black hole with scalar field

Evidence for the existence of a novel class of supersymmetric black holes with AdS 5 ×S 5 asymptotics

Vacuum energy in Kerr-AdS black holes

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Evidence for the existence of a novel class of supersymmetric black holes with AdS ₅ ×S ⁵ asymptotics