scholarly journals NOTES ON FIVE-DIMENSIONAL KERR BLACK HOLES

2006 ◽  
Vol 21 (11) ◽  
pp. 2331-2352 ◽  
Author(s):  
MAKOTO SAKAGUCHI ◽  
YUKINORI YASUI
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Kerr Black Hole ◽  
Weyl Curvature ◽  
Null Geodesics ◽  
Ricci Flat ◽  
Space Star ◽  
Kerr Space ◽  
Kerr Black Holes

The geometry of five-dimensional Kerr black holes is discussed based on geodesics and Weyl curvatures. Kerr-Star space, Star-Kerr space and Kruskal space are naturally introduced by using special null geodesics. We show that the geodesics of AdS Kerr black hole are integrable, which generalizes the result of Frolov and Stojkovic. We also show that five-dimensional AdS Kerr black holes are isospectrum deformations of Ricci-flat Kerr black holes in the sense that the eigenvalues of the Weyl curvature are preserved.

scholarly journals SEMICLASSICAL CORRECTIONS TO THE CARDY–VERLINDE FORMULA OF KERR BLACK HOLES

2008 ◽  
Vol 23 (13) ◽  
pp. 2047-2053 ◽  
Author(s):  
M. R. SETARE
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Central Charge ◽  
Kerr Black Hole ◽  
Gravitational Effect ◽  
The Self ◽  
Entropy Formula ◽  
Verlinde Formula ◽  
Kerr Black Holes

In this paper, we compute the corrections to the Cardy–Verlinde formula of four-dimensional Kerr black hole. These corrections are considered within the context of KKW analysis and arise as a result of the self-gravitational effect. Then we show that one can take into account the semiclassical corrections of the Cardy–Verlinde entropy formula by only redefining the Virasoro operator L0 and the central charge c.

scholarly journals AREA SPECTRUM OF KERR AND EXTREMAL KERR BLACK HOLES FROM QUASINORMAL MODES

2005 ◽  
Vol 20 (25) ◽  
pp. 1923-1932 ◽  
Author(s):  
MOHAMMAD R. SETARE ◽  
ELIAS C. VAGENAS
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Quasinormal Modes ◽  
Kerr Black Hole ◽  
Area Spectrum ◽  
The Real ◽  
Hole Area ◽  
Newman Black Hole ◽  
Discrete Area ◽  
Kerr Black Holes

Motivated by the recent interest in quantization of black hole area spectrum, we consider the area spectrum of Kerr and extremal Kerr black holes. Based on the proposal by Bekenstein and others that the black hole area spectrum is discrete and equally spaced, we implement Kunstatter's method to derive the area spectrum for the Kerr and extremal Kerr black holes. The real part of the quasinormal frequencies of Kerr black hole used for this computation is of the form mΩ where Ω is the angular velocity of the black hole horizon. The resulting spectrum is discrete but not as expected uniformly spaced. Thus, we infer that the function describing the real part of quasinormal frequencies of Kerr black hole is not the correct one. This conclusion is in agreement with the numerical results for the highly damped quasinormal modes of Kerr black hole recently presented by Berti, Cardoso and Yoshida. On the contrary, extremal Kerr black hole is shown to have a discrete area spectrum which in addition is evenly spaced. The area spacing derived in our analysis for the extremal Kerr black hole area spectrum is not proportional to ln 3. Therefore, it does not give support to Hod's statement that the area spectrum [Formula: see text] should be valid for a generic Kerr–Newman black hole.

scholarly journals A Zeroth Law Compatible Model to Kerr Black Hole Thermodynamics

2016 ◽  
Author(s):  
Viktor G. Czinner ◽  
Hideo Iguchi
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Stability Problem ◽  
Turning Point ◽  
Energy Parameter ◽  
Kerr Black Hole ◽  
Mass Energy ◽  
Temperature Function ◽  
Nonadditive Entropy ◽  
Kerr Black Holes

We consider the thermodynamic and stability problem of Kerr black holes arising from the nonextensive/nonadditive nature of the Bekenstein-Hawking entropy formula. Nonadditive thermodynamics is often criticized by asserting that the zeroth law cannot be compatible with nonadditive composition rules, so in this work we follow the so-called formal logarithm method to derive an additive entropy function for Kerr black holes satisfying also the zeroth law's requirement. Starting from the most general, equilibrium compatible, nonadditive entropy composition rule of Abe, we consider the simplest, non-parametric approach that is generated by the explicit nonadditive form of the Bekenstein-Hawking formula. This analysis extends our previous results on the Schwarzschild case and shows that the zeroth law compatible temperature function in the model is independent of the mass-energy parameter of the black hole. By applying the Poincaré turning point method we also study the thermodynamic stability problem in the system.

scholarly journals Exotic orbits due to spin–spin coupling around Kerr black holes

2017 ◽  
Vol 27 (01) ◽  
pp. 1750179 ◽  
Author(s):  
Wen-Biao Han ◽  
Shu-Cheng Yang
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Equatorial Plane ◽  
Strong Field ◽  
Kerr Black Hole ◽  
Spin Coupling ◽  
Spinning Particles ◽  
Test Particles ◽  
Kerr Black Holes ◽  
Large Spins

We report exotic orbital phenomena of spinning test particles orbiting around a Kerr black hole, i.e. some orbits of spinning particles are asymmetrical about the equatorial plane. When a nonspinning test particle orbits around a Kerr black hole in a strong field region, due to relativistic orbital precessions, the pattern of trajectories is symmetrical about the equatorial plane of the Kerr black hole. However, the patterns of the spinning particles’ orbit are no longer symmetrical about the equatorial plane for some orbital configurations and large spins. We argue that these asymmetrical patterns come from the spin–spin interactions between spinning particles and Kerr black holes, because the directions of spin–spin forces can be arbitrary, and distribute asymmetrically about the equatorial plane.

Superradiant stability of the Kerr black hole

2020 ◽  
Vol 29 (01) ◽  
pp. 2050009 ◽  
Author(s):  
Wen-Xiang Chen ◽  
Zi-Yang Huang
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Kerr Black Hole ◽  
Algebraic Methods ◽  
Stability Conditions ◽  
Parameter Region ◽  
Kerr Black Holes ◽  
The Stability ◽  
Scalar Perturbations

We know that Kerr black holes are stable for specific conditions. In this paper, we use algebraic methods to prove the stability of the Kerr black hole against certain scalar perturbations. This provides new results for the previously obtained superradiant stability conditions of Kerr black hole. Hod proved that Kerr black holes are stable to massive perturbations in the regime [Formula: see text]. In this paper, we consider some other situations of the stability of the black hole in the complementary parameter region[Formula: see text]

scholarly journals Gedanken experiments at high-order approximation: Kerr black hole cannot be overspun

2021 ◽  
Vol 2021 (9) ◽  
Author(s):  
Aofei Sang ◽  
Jie Jiang
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Order Approximation ◽  
Energy Condition ◽  
Kerr Black Hole ◽  
Null Energy Condition ◽  
Higher Order ◽  
High Order ◽  
Order Perturbation ◽  
Kerr Black Holes

Abstract Sorce and Wald proposed a new version of gedanken experiments to examine the weak cosmic censorship conjecture (WCCC) in Kerr-Newmann black holes. However, their discussion only includes the second-order approximation of perturbation and there exists an optimal condition such that the validity of the WCCC is determined by the higher-order approximations. Therefore, in this paper, we extended their discussions into the high-order approximations to study the WCCC in a nearly extremal Kerr black hole. After assuming that the spacetime satisfies the stability condition and the perturbation matter fields satisfy the null energy condition, based on the Noether charge method by Iyer and Wald, we completely calculate the first four order perturbation inequalities and discuss the corresponding gedanken experiment to overspin the Kerr black hole. As a result, we find that the nearly extremal Kerr black holes cannot be destroyed under the fourth-order approximation of perturbation. Then, by using the mathematical induction, we strictly prove the nth order perturbation inequality when the first (n − 1) order perturbation inequalities are saturated. Using these results, we discuss the first 100 order approximation of the gedanken experiments and find that the WCCC in Kerr black hole is valid under the higher-order approximation of perturbation. Our investigation implies that the WCCC might be strictly satisfied in Kerr black holes under the perturbation level.

scholarly journals Solutions of Kerr Black Holes subject to Naked Singularity and Wormholes

2020 ◽  
Author(s):  
Deep Bhattacharjee
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Event Horizon ◽  
Kerr Black Hole ◽  
Naked Singularity ◽  
The Other ◽  
Cauchy Horizon ◽  
White Hole ◽  
Kerr Black Holes ◽  
The Way

The existence of the “Naked Singularity" has been shown taking the advantage of the Ring Singularity of the Kerr Black Hole and thereby making the way to manipulate the mathematics by taking the larger root of Δ as zero and thereby vanishing the ergosphere and event horizon making the way for the naked ring singularity which can be easily connected via a cylindrical wormhole and as ‘a wormhole is a black hole without an event horizon’ therefore, this cylindrical connection paved the way for the Einstein-Rosen Bridge allowing particles or null rays to travel from one universe to another ending up in a future directed Cauchy horizon while changing constantly from spatial to temporal and again spatial paving the entrance to another Kerr Black hole (which would act as a white hole) in the other universes.

scholarly journals Gravitomagnetism and pulsar beam precession near a Kerr black hole

2019 ◽  
Vol 490 (3) ◽  
pp. 3262-3286 ◽  
Author(s):  
Prashant Kocherlakota ◽  
Pankaj S Joshi ◽  
Sudip Bhattacharyya ◽  
Chandrachur Chakraborty ◽  
Alak Ray ◽  
...  
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Kerr Black Hole ◽  
Theoretical Work ◽  
Pulse Frequency ◽  
Spin Precession ◽  
Naked Singularities ◽  
Frame Dragging ◽  
Kerr Black Holes ◽  
Short Time

ABSTRACT A rotating black hole causes the spin axis of a nearby pulsar to precess due to geodetic and gravitomagnetic frame-dragging effects. The aim of our theoretical work here is to explore how this spin precession can modify the rate at which pulses are received on Earth. Towards this end, we obtain the complete evolution of the beam vectors of pulsars moving on equatorial circular orbits in the Kerr space–time, relative to asymptotic fixed observers. We proceed to establish that such spin precession effects can significantly modify observed pulse frequencies and, in specific, we find that the observed pulse frequency rises sharply as the orbit shrinks, potentially providing a new way to locate horizons of Kerr black holes, even if observed for a very short time period. We also discuss implications for detections of sub-millisecond pulsars, pulsar nulling, quasi-periodic oscillations, multiply peaked pulsar Fourier profiles, and how Kerr black holes can potentially be distinguished from naked singularities.

scholarly journals U(N)-MONOPOLES ON KERR BLACK HOLE AND ITS ENTROPY

1998 ◽  
Vol 13 (18) ◽  
pp. 1495-1507 ◽  
Author(s):  
YU. P. GONCHAROV
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Fine Structure ◽  
Explicit Form ◽  
Moduli Space ◽  
Kerr Black Hole ◽  
Black Hole Entropy ◽  
Statistical Ensemble ◽  
Splitting Theorem ◽  
Kerr Black Holes

We describe U(N)-monopoles (N>1) on Kerr black holes using the parameters of the moduli space of holomorphic vector U(N)-bundles over [Formula: see text] with the help of the Grothendieck splitting theorem. For N = 2,3 we obtain this description in an explicit form as well as the estimates for the corresponding monopole masses. This gives us a possibility to adduce some reasonings in favor of the existence of both a fine structure for Kerr black holes and the statistical ensemble tied with it which might generate the Kerr black hole entropy.

scholarly journals Fermat’s principle in black-hole spacetimes

2018 ◽  
Vol 27 (14) ◽  
pp. 1847025 ◽  
Author(s):  
Shahar Hod
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Black Hole Spacetimes ◽  
Fermat’S Principle ◽  
Kerr Black Holes ◽  
Fermat's Principle ◽  
Asymptotic Observers

Black-hole spacetimes are known to possess closed light rings. We here present a remarkably compact theorem which reveals the physically intriguing fact that these unique null circular geodesics provide the fastest way, as measured by asymptotic observers, to circle around spinning Kerr black holes.

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