dS Black Hole Research Articles

Holographic Q-picture of Kerr–Newman–AdS–dS black hole

In this article, we show that a four-dimensional Kerr–Newman–AdS–dS black hole could be described by two different holographic two-dimensional conformal field theories. The first description, in view of the angular momentum, has been well discussed in Chen and Long (2010) [23]. The other alternative dual picture, however, is somehow overlooked. This new description, in view of the charge, provides another holographic correspondence. This picture again is supported not only by the match of the macroscopic entropy with the counting of microscopic degrees of freedom via the Cardy formula and also by the agreement on the real-time correlator in the superradiant scattering.

ON THE CFT DUALS FOR NEAR-EXTREMAL BLACK HOLES

We consider Kerr–Newman–AdS–dS black holes near extremality and work out the near-horizon geometry of these near-extremal black holes. We identify the exact U (1)L× U (1)R isometries of the near-horizon geometry and provide boundary conditions enhancing them to a pair of commuting Virasoro algebras. The conserved charges of the corresponding asymptotic symmetries are found to be well-defined and nonvanishing and to yield central charges cL≠0 and cR = 0. The Cardy formula subsequently reproduces the Bekenstein–Hawking entropy of the black hole. This suggests that the near-extremal Kerr–Newman–AdS–dS black hole is holographically dual to a non-chiral two-dimensional conformal field theory.

Scalar Spheroidal Harmonics in Five Dimensional Kerr-(A)dS

We derive expressions for the general five-dimensional metric for Kerr-(A)dS black holes. The Klein-Gordon equation is explicitly separated and we show that the angular part of the wave equation leads to just one spheroidal wave equation, which is also that for charged five-dimensional Kerr-(A)dS black holes. We present results for the perturbative expansion of the angular eigenvalue in powers of the rotation parameters up to 6th order and compare numerically with the continued fraction method.

Black holes in Born-Infeld extended new massive gravity

In this paper we find different types of black holes for the Born-Infeld extended new massive gravity. Our solutions include (un)charged warped (A)dS black holes for four and six derivative expanded action. We also look at the black holes in unexpanded BI action. In each case we calculate the entropy, angular momentum and mass of the black holes. We also find the central charges for the CFT duals.

Formula omitted] superparticle near horizon of extreme Kerr–Newman–AdS–dS black hole

Conformal mechanics related to the near horizon extreme Kerr–Newman–AdS–dS black hole is studied. A unique N = 2 supersymmetric extension of the conformal mechanics is constructed.

Holographic description of Kerr–Bolt–AdS–dS spacetimes

We show that there exists a holographic 2D CFT description of a Kerr–Bolt–AdS–dS spacetime. We first consider the wave equation of a massless scalar field propagating in extremal Kerr–Bolt–AdS–dS spacetimes and find in the “near region”, the wave equation in extremal limit could be written in terms of the SL ( 2 , R ) quadratic Casimir. This suggests that there exist dual CFT descriptions of these black holes. In the probe limit, we compute the scattering amplitudes of the scalar off the extremal black holes and find perfect agreement with the CFT prediction. Furthermore we study the holographic description of the generic four-dimensional non-extremal Kerr–Bolt–AdS–dS black holes. We find that if focusing on the near-horizon region, for the massless scalar scattering in the low-frequency limit, the radial equation could still be rewritten as the SL ( 2 , R ) quadratic Casimir, suggesting the existence of dual 2D description. We read the temperatures of the dual CFT from the conformal coordinates and obtain the central charges by studying the near-horizon geometry of near-extremal black holes. We recover the macroscopic entropy from the microscopic counting. We also show that for the super-radiant scattering, the retarded Greenʼs functions and the corresponding absorption cross sections are in perfect match with CFT prediction.

On hidden symmetries of extremal Kerr–NUT–AdS–dS black holes

It is well known that the Kerr–NUT–AdS–dS black hole admits two linearly independent Killing vectors and possesses a hidden symmetry generated by a rank-2 Killing tensor. The near-horizon geometry of an extremal Kerr–NUT–AdS–dS black hole admits four linearly independent Killing vectors, and we show how the hidden symmetry of the black hole itself is carried over by means of a modified Killing–Yano potential which is given explicitly. We demonstrate that the corresponding Killing tensor of the near-horizon geometry is reducible as it can be expressed in terms of the Casimir operators formed by the four Killing vectors.

Hawking temperature in Taub-NUT (A)dS spaces via the generalized uncertainty principle

Using the extended forms of the Heisenberg uncertainty principle from string theory and the quantum gravity theory, we drived Hawking temperature of a Taub-Nut-(A)dS black hole. In spite of their distinctive natures such as asymptotically locally flat and breakdown of the area theorem of the horizon for the black holes, we show that the corrections to Hawking temperature by the generalized versions of the the Heisenberg uncertainty principle increases like the Schwarzschild-(A)dS black hole and give the reason why the Taub-Nut-(A)dS metric may have AdS/CFT dual picture.

Radiation Spectrum and Correction Entropy of (n+4)-dimensional Kerr-(A)dS Black Hole

We extend the classical Damour-Ruffini method and discuss Hawking radiation of an (n+4)-dimensional Kerr-(A)dS black hole. We not only derive the radiation spectrum that satisfies the unitary principle but also obtain the correction term of Bekenstein-Hawking entropy.

Asymptotic iteration method for spheroidal harmonics of higher-dimensional Kerr-(A)dS black holes

In this work we calculate the angular eigenvalues of the ($n+4$)-dimensional simply rotating Kerr-(A)dS spheroidal harmonics using the asymptotic iteration method. We make some comparisons between this method and that of the continued fraction method and use the latter to check our results. We also present analytic expressions for the small rotation limit up to $O({c}^{3})$ with the coefficient of each power up to $O({\ensuremath{\alpha}}^{2})$, where $c=a\ensuremath{\omega}$ and $\ensuremath{\alpha}={a}^{2}\ensuremath{\Lambda}$ ($a$ is the angular velocity, $\ensuremath{\omega}$ the frequency, and $\ensuremath{\Lambda}$ the cosmological constant).

NONCOMMUTATIVE D-BRANE WORLD, BLACK HOLES AND EXTRA DIMENSIONS

Inspired by the space-time noncommutativity on a D5-brane world, in a type IIB string theory, we explore the possibility of an emergent 4D ordinary space-time in the formalism. In particular, a curved D3-brane dynamics is worked out to obtain an axially symmetric and a spherically symmetric AdS and dS black holes. Extremal geometries are analyzed, using the noncommutative scaling. The emerging two dimensional semi-classical black holes are investigated to yield evidence for extra dimensions in the curved brane-world. Interestingly, a tunneling between dS to AdS vacua in the formalism is briefly discussed by incorporating the Hagedorn transitions in string theory.

The absence of normalizable time-periodic solutions for the Dirac equation in the Kerr–Newman–dS black hole background

We consider the Dirac equation on the background of a Kerr–Newman–de Sitter black hole. By performing variable separation, we show that no time-periodic and normalizable solution of the Dirac equation is allowed, which amounts to the absence of quantum bound states for the Dirac Hamiltonian. This conclusion holds true even for extremal black holes. With respect to previously considered cases, the novelty is represented by the presence, in addition to a black hole event horizon, of a cosmological (non-degenerate) event horizon, which is at the root of the possibility to draw a conclusion on the aforementioned topic in a straightforward way even in the extremal case.

Hawking temperature of a Kerr–Newman–dS black hole from tunneling

We study the Hawking radiation of the Kerr–Newman–dS black hole on its event horizon and cosmological horizon from the tunneling approach of Parikh and Wilczek. In order to eliminate the motion on the rotating degree of freedom of a tunneling particle coming from the rotation of the Kerr–Newman–dS black hole, we choose a reference system that is co-rotating with the black hole horizon. Using such a method, we can derive the Hawking temperature of a general rotating black hole from the tunneling approach clearly. Then, to use the general result to the Kerr–Newman–dS case, we reproduce the Hawking temperatures of the Kerr–Newman–dS black hole on its event horizon and cosmological horizon from the tunneling approach.

Modified dispersion relations and (A)dS Schwarzschild black holes

In this Letter we investigate the impact of modified dispersion relations (MDR) on (Anti)de Sitter–Schwarzschild black holes. In this context we find the temperature of black holes can be derived with important corrections. In particular given a specific MDR the temperature has a maximal value such that it can prevent black holes from total evaporation. The entropy of the (A)dS black holes is also obtained with a logarithmic correction.

Comment on ‘Non-monotonic orbital velocity profiles around rapidly rotating Kerr–(anti-)de Sitter black holes’

A critical discussion of the recently published results (Müller A and Aschenbach B 2007 Class. Quantum Grav. 24 2637) on the non-monotonic orbital velocity profiles of the Keplerian motion of test particles and ℓ = const motion of test perfect fluid around K(a)dS black holes is given, and the discrepancies concerned with the existence of the non-monotonicity in dependence of the spacetime parameters are corrected. Moreover, a new non-monotonic behaviour of the Keplerian orbital velocity in the Kerr–anti-de Sitter spacetimes is highlighted.

Integrability and the Kerr-(A)dS black hole in five dimensions

In this paper we prove that the Hamilton-Jacobi equation for a particle in the five dimensional Kerr-(A)dS black hole is separable, for arbitrary rotation parameters. As a result we find an irreducible Killing tensor. We also consider the Klein-Gordon equation in this background and show that this is also separable. Finally, we comment on extensions and implications of these results.

Nuttier (A)dS black holes in higher dimensions

We construct new solutions of the vacuum Einstein field equations with cosmological constant. These solutions describe spacetimes with non-trivial topology, which are asymptotically dS, AdS or flat. For a negative cosmological constant these solutions are NUT charged generalizations of the topological black-hole solutions in higher dimensions. We also point out the existence of such NUT charged spacetimes in odd dimensions and explicitly construct such spaces in five and seven dimensions. The existence of such spacetimes with non-trivial topology is closely related to the existence of the cosmological constant. Finally, we discuss the global structure of such solutions and possible applications in string theory.

Pair of accelerated black holes in a de Sitter background: The dSCmetric

Following the work of Kinnersley and Walker for flat spacetimes, we have analyzed the anti-de Sitter C-metric in a previous paper. In the de Sitter case, Podolsky and Griffiths have established that the de Sitter C-metric (dS C-metric) found by Plebanski and Demianski describes a pair of accelerated black holes in the dS background with the acceleration being provided (in addition to the cosmological constant) by a strut that pushes away the two black holes or, alternatively, by a string that pulls them. We extend their analysis mainly in four directions. First, we draw the Carter-Penrose diagrams of the massless uncharged dS C-metric, of the massive uncharged dS C-metric and of the massive charged dS C-metric. These diagrams allow us to clearly identify the presence of two dS black holes and to conclude that they cannot interact gravitationally. Second, we revisit the embedding of the dS C-metric in the 5D Minkowski spacetime and we represent the motion of the dS C-metric origin in the dS 4-hyperboloid as well as the localization of the strut. Third, we comment on the physical properties of the strut that connects the two black holes. Finally, we find the range of parameters that correspond to non-extreme black holes, extreme black holes, and naked particles.

FRIEDMANN–ROBERTSON–WALKER BRANE COSMOLOGICAL EQUATIONS FROM THE FIVE-DIMENSIONAL BULk (A)dS BLACK HOLE

In the first part of this work we review the equations of motion for the brane presented in Friedmann–Robertson–Walker (FRW) form, when the bulk is five-dimensional (A)dS Black Hole. The spacelike (timelike) FRW brane equations are considered from the point of view of their representation in the form similar to two-dimensional CFT entropy, the so-called Cardy–Verlinde (CV) formula. The following five-dimensional gravities are reviewed: Einstein, Einstein–Maxwell and Einstein with brane quantum corrections. The second part of the work is devoted to the study of FRW brane equations and their representation in CV form, brane induced matter and brane cosmology in Einstein–Gauss–Bonnet (GB) gravity. In particular, we focus on the inflationary brane cosmology. The energy conditions for brane matter are also analyzed. We show that for some values of GB coupling constant (bulk is AdS BH) the brane matter is not CFT. Its energy density and pressure are not always positive. The appearance of logarithmic corrections in brane cosmology is discussed.

Higher dimensional flat embeddings of (2+1)-dimensional black holes

We obtain the higher dimensional global flat embeddings of static, rotating, and charged BTZ black holes. On the other hand, we also study the similar higher dimensional flat embeddings of the (2+1) de Sitter black holes which are the counterparts of the anti-de Sitter BTZ black holes. As a result, the charged dS black hole is shown to be embedded in (3+2) GEMS, contrast to the charged BTZ one having (3+3) GEMS structure.