923 research outputs found
Holographic Duals of Black Holes in Five-dimensional Minimal Supergravity
We examine the dual conformal field theory for extremal charged black holes
in five-dimensional minimal supergravity with 2 independent angular momenta.
The conformal field theory Virasoro algebra, central charge, and temperature
are calculated. Additionally the conformal field theory entropy is calculated
using the Cardy formula and agrees with the Bekenstein-Hawking black hole
entropy. The central charges are directly proportional to the angular momentum
components of the black hole. In five and higher dimensions, rotations of the
spacetime correspond to rotations of the central charges leading to an apparent
symmetry relating the conformal field theories dual to each black hole. A
rotationally invariant central charge, which is proportional to the total
angular momentum, is used to discuss the supersymmetric BMPV black hole limits.Comment: inaccurate descriptions are clarifie
Extremal dilatonic black holes in 4D Gauss-Bonnet gravity
This is a report of our recent investigation on the extremal dilatonic black
holes in four dimensional Gauss-Bonnet gravity. We found that a global solution
can exist only when the dilaton coupling is less than a critical value which
can be determined numerically. Moreover, the black hole horizon is stretched by
the Gauss-Bonnet correction and the entropy is twice the value given by
Bekenstein-Hawking formula.Comment: 4 pages, contribution to the proceedings of the 8th Asia-Pacific
International Conference on Gravitation and Astrophysics (ICGA8
Viscous dissipative effects in isotropic brane cosmology
We consider the dynamics of a viscous cosmological fluid in the generalized
Randall-Sundrum model for an isotropic brane. To describe the dissipative
effects we use the Israel-Hiscock-Stewart full causal thermodynamic theory. In
the limiting case of a stiff cosmological fluid with pressure equal to the
energy density, the general solution of the field equations can be obtained in
an exact parametric form for a cosmological fluid with constant bulk viscosity
and with a bulk viscosity coefficient proportional to the square root of the
energy density, respectively. The obtained solutions describe generally
non-inflationary brane worlds, starting from a singular state. During this
phase of evolution the comoving entropy of the Universe is an increasing
function of time, and thus a large amount of entropy is created in the brane
world due to viscous dissipative processes.Comment: 15 pages, 11 figure
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