50,816 research outputs found

### Notes on Five-dimensional 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.Comment: 23 pages, 5 figures; analyses on the Weyl curvature of AdS Kerr black
holes are extended, an appendix and references are adde

### Joule-Thomson Expansion of Kerr-AdS Black Holes

In this paper, we study Joule-Thomson expansion for Kerr-AdS black holes in
the extended phase space. Joule-Thomson expansion formula of Kerr-AdS black
holes is derived. We investigate both isenthalpic and numerical inversion
curves in the T-P plane and demonstrate the cooling-heating regions for
Kerr-AdS black holes. We also calculate the ratio between minimum inversion and
critical temperatures for Kerr-AdS black holes.Comment: 10 pages, 3 figures. Minor revision

### Initial Data and Coordinates for Multiple Black Hole Systems

We present here an alternative approach to data setting for spacetimes with
multiple moving black holes generalizing the Kerr-Schild form for rotating or
non-rotating single black holes to multiple moving holes. Because this scheme
preserves the Kerr-Schild form near the holes, it selects out the behaviour of
null rays near the holes, may simplify horizon tracking, and may prove useful
in computational applications. For computational evolution, a discussion of
coordinates (lapse function and shift vector) is given which preserves some of
the properties of the single-hole Kerr-Schild form

### Logarithmic Corrections to Rotating Extremal Black Hole Entropy in Four and Five Dimensions

We compute logarithmic corrections to the entropy of rotating extremal black
holes using quantum entropy function i.e. Euclidean quantum gravity approach.
Our analysis includes five dimensional supersymmetric BMPV black holes in type
IIB string theory on T^5 and K3 x S^1 as well as in the five dimensional CHL
models, and also non-supersymmetric extremal Kerr black hole and slowly
rotating extremal Kerr-Newmann black holes in four dimensions. For BMPV black
holes our results are in perfect agreement with the microscopic results derived
from string theory. In particular we reproduce correctly the dependence of the
logarithmic corrections on the number of U(1) gauge fields in the theory, and
on the angular momentum carried by the black hole in different scaling limits.
We also explain the shortcomings of the Cardy limit in explaining the
logarithmic corrections in the limit in which the (super)gravity description of
these black holes becomes a valid approximation. For non-supersymmetric
extremal black holes, e.g. for the extremal Kerr black hole in four dimensions,
our result provides a stringent testing ground for any microscopic explanation
of the black hole entropy, e.g. Kerr/CFT correspondence.Comment: LaTeX file, 50 pages; v2: added extensive discussion on the relation
between boundary condition and choice of ensemble, modified analysis for
slowly rotating black holes, all results remain unchanged, typos corrected;
v3: minor additions and correction

### Geometry of Higher-Dimensional Black Hole Thermodynamics

We investigate thermodynamic curvatures of the Kerr and Reissner-Nordstr\"om
(RN) black holes in spacetime dimensions higher than four. These black holes
possess thermodynamic geometries similar to those in four dimensional
spacetime. The thermodynamic geometries are the Ruppeiner geometry and the
conformally related Weinhold geometry. The Ruppeiner geometry for $d=5$ Kerr
black hole is curved and divergent in the extremal limit. For $d \geq 6$ Kerr
black hole there is no extremality but the Ruppeiner curvature diverges where
one suspects that the black hole becomes unstable. The Weinhold geometry of the
Kerr black hole in arbitrary dimension is a flat geometry. For RN black hole
the Ruppeiner geometry is flat in all spacetime dimensions, whereas its
Weinhold geometry is curved. In $d \geq 5$ the Kerr black hole can possess more
than one angular momentum. Finally we discuss the Ruppeiner geometry for the
Kerr black hole in $d=5$ with double angular momenta.Comment: 8 pages, 2 figures, RevTex, References adde

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