161 research outputs found
No Ghost State in the Brane World
We discuss the role of the trace part of metric fluctuations in the
Randall-Sundrum scenario of gravity. Without the matter, this field
() is a gauge-dependent term, and thus it can be gauged
away. But, including the uniform source , this field satisfies
the linearized equation . This may
correspond to the scalar in the bending of the brane due to the
localized source. Considering the case of longitudinal perturbations (), one finds the source relation
, which leads to the ghost states in the
massive modes. In addition, if one requires , it is
found that in the limit of we have the massless spin-2
propagation without the ghost state. This exactly corresponds to the same
situation as in the intermediate scales of Gregory-Rubakov-Sibiryakov (GRS)
model.Comment: 7 pages, no figure, the version to appear in PLB, comments on the
matter source and references added, main results unchange
Quantized Black Hole and Heun function
Following the simple proposal by He and Ma for quantization of a black
hole(BH) by Bohr's idea about the atoms, we discussed the solvability of the
wave equation for such a BH. We superficial solved the associated Schrodinger
equation. The eigenfunction problem reduces to HeunB differential equation
which is a natural generalization of the hypergeometric differential equation.
In other words, the spectrum can be determined by solving the Heun's
differential equation.Comment: 9 pages,Title Changed, 3 figures, Refrences adde
Slowly rotating black holes in the Horava-Lifshitz gravity
We investigate slowly rotating black holes in the Ho\v{r}ava-Lifshitz (HL)
gravity. For and , we find a slowly rotating black
hole of the Kehagias-Sfetsos solution in asymptotically flat spacetimes. We
discuss their thermodynamic properties by computing mass, temperature, angular
momentum, and angular velocity on the horizon.Comment: 12 pages, no figures, version to appear in EPJ
Thermodynamics of Chaplygin gas
We clarify thermodynamics of the Chaplygin gas by introducing the
integrability condition. All thermal quantities are derived as functions of
either volume or temperature. Importantly, we find a new general equation of
state, describing the Chaplygin gas completely. We confirm that the Chaplygin
gas could show a unified picture of dark matter and energy which cools down
through the universe expansion without any critical point (phase transition).Comment: 5 pages, 4 figures, version "Accepted for publication in Astrophysics
& Space Science
Phase transitions for the Lifshitz black holes
We study possibility of phase transitions between Lifshitz black holes and
other configurations by using free energies explicitly. A phase transition
between Lifshitz soliton and Lifshitz black hole might not occur in three
dimensions. We find that a phase transition between Lifshitz and BTZ black
holes unlikely occurs because they have different asymptotes. Similarly, we
point out that any phase transition between Lifshitz and black branes unlikely
occurs in four dimensions since they have different asymptotes. This is
consistent with a necessary condition for taking a phase transition in the
gravitational system, which requires the same asymptote.Comment: 19 pages, 7 figures, a revised version to appear in EPJ
Randall-Sundrum Gauge in the Brane World
We discuss the Randall-Sundrum (RS) choice for in the brane-world.
We begin with the de Donder gauge (transverse-tracefree) including
scalar(), vector() and tensor() in five
dimensions for comparison. One finds that and . This
leads to the RS choice. It appears that the RS choice is so restrictive for the
five massless states, whereas it is unique for describing the massive states.
Furthermore, one can establish the stability of the RS solution with the RS
choice only.Comment: corrected some typographical mistakes, 11 pages with ReVTeX, no
figur
The absence of the Kerr black hole in the Ho\v{r}ava-Lifshitz gravity
We show that the Kerr metric does not exist as a fully rotating black hole
solution to the modified Ho\v{r}ava-Lifshitz (HL) gravity with
and case. We perform it by showing that the Kerr metric does not
satisfy full equations derived from the modified HL gravity.Comment: 35 pages, no figure
Logarithmic corrections to the Bekenstein_Hawking entropy for five-dimensional black holes and de Sitter spaces
We calculate corrections to the Bekenstein-Hawking entropy formula for the
five-dimensional topological AdS (TAdS)-black holes and topological de Sitter
(TdS) spaces due to thermal fluctuations. We can derive all thermal properties
of the TdS spaces from those of the TAdS black holes by replacing by .
Also we obtain the same correction to the Cardy-Verlinde formula for TAdS and
TdS cases including the cosmological horizon of the Schwarzschild-de Sitter
(SdS) black hole. Finally we discuss the AdS/CFT and dS/CFT correspondences and
their dynamic correspondences.Comment: 9 pages, version to appear in PL
Quasinormal modes and hidden conformal symmetry in the Reissner-Nordstrom black hole
It is shown that the scalar wave equation in the near-horizon limit respects
a hidden SL(2,R) invariance in the Reissner-Nordstrom (RN) black hole
spacetimes. We use the SL(2,R) symmetry to determine algebraically the purely
imaginary quasinormal frequencies of the RN black hole. We confirm that these
are exactly quasinormal modes of scalar perturbation around the near-extremal
black hole.Comment: 17 pages, 1 figure, version to appear in EPJ
Dilaton gravity approach to three dimensional Lifshitz black hole
The z=3 Lifshitz black hole is an exact black hole solution to the new
massive gravity in three dimensions. In order to understand this black hole
clearly, we perform a dimensional reduction to two dimensional dilaton gravity
by utilizing the circular symmetry. Considering the linear dilaton, we find the
same Lifshitz black hole in two dimensions. This implies that all thermodynamic
quantities of the z=3 Lifshitz black hole could be obtained from its
corresponding black hole in two dimensions. As a result, we derive the
temperature, mass, heat capacity, Bekesnstein-Hawking entropy, and free energy.Comment: 13 pages, 1 figure, version to appear in EPJ
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