519 research outputs found
Charged Anti-de Sitter BTZ black holes in Maxwell- gravity
Inspired by the BTZ formalism, we discuss the Maxwell- gravity in
(2+1)-dimensions. The main task is to derive exact solutions for a special form
of , with being the torsion scalar of
Weitzenb\ddot{\mbox{o}}ck geometry. To this end, a triad field is applied to
the equations of motion of charged and sets of circularly symmetric
non-charged and charged solutions have been derived. We show that, in the
charged case, the monopole-like and the terms are linked by a
correlative constant despite of known results in teleparallel geometry and its
extensions [39]. Furthermore, it is possible to show that the event horizon is
not identical with the Cauchy horizon due to such a constant. The singularities
and the horizons of these black holes are examined: they are new and have no
analogue in literature due to the fact that their curvature singularities are
soft. We calculate the energy content of these solutions by using the general
vector form of the energy-momentum within the framework of gravity.
Finally, some thermodynamical quantities, like entropy and Hawking temperature,
are derived.Comment: 15 pages, accepted for publication in IJMP
-dimensional charged Anti-de-Sitter black holes in gravity
We present a -dimensional charged Anti-de-Sitter black hole solutions in
gravity, where and . These solutions are
characterized by flat or cylindrical horizons. The interesting feature of these
solutions is the existence of inseparable electric monopole and quadrupole
terms in the potential which share related momenta, in contrast with most of
the known charged black hole solutions in General Relativity and its
extensions. Furthermore, these solutions have curvature singularities which are
milder than those of the known charged black hole solutions in General
Relativity and Teleparallel Gravity. This feature can be shown by calculating
some invariants of curvature and torsion tensors. Furthermore, we calculate the
total energy of these black holes using the energy-momentum tensor. Finally, we
show that these charged black hole solutions violate the first law of
thermodynamics in agreement with previous results.Comment: 11 Pages, will appear in JHE
On the energy of charged black holes in generalized dilaton-axion gravity
In this paper we calculate the energy distribution of some charged black
holes in generalized dilaton-axion gravity. The solutions correspond to charged
black holes arising in a Kalb-Ramond-dilaton background and some existing
non-rotating black hole solutions are recovered in special cases. We focus our
study to asymptotically flat and asymptotically non-flat types of solutions and
resort for this purpose to the M{\o}ller prescription. Various aspects of
energy are also analyzed.Comment: LaTe
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Giant Adrenal Myelolipoma Masquerading as Heart Failure
Adrenal myelolipomas are rare benign tumors of the adrenal cortex composed of adipose and hematopoietic cells. They have been postulated to arise from repeated stimulation by stress, inflammation and ACTH oversecretion. Myelolipomas are usually detected incidentally on imaging and do not require any active intervention besides regular follow-up by imaging. However, myelolipomas may insidiously grow to large sizes and cause mass effects and hemorrhage. Timely diagnosis and surgical resection are curative and lifesaving
Teleparallel Energy-Momentum Distribution of Static Axially Symmetric Spacetimes
This paper is devoted to discuss the energy-momentum for static axially
symmetric spacetimes in the framework of teleparallel theory of gravity. For
this purpose, we use the teleparallel versions of Einstein, Landau-Lifshitz,
Bergmann and Mller prescriptions. A comparison of the results shows
that the energy density is different but the momentum turns out to be constant
in each prescription. This is exactly similar to the results available in
literature using the framework of General Relativity. It is mentioned here that
Mller energy-momentum distribution is independent of the coupling
constant . Finally, we calculate energy-momentum distribution for the
Curzon metric, a special case of the above mentioned spacetime.Comment: 14 pages, accepted for publication in Mod. Phys. Lett.
Cosmological applications in Kaluza-Klein theory
The field equations of Kaluza-Klein (KK) theory have been applied in the
domain of cosmology. These equations are solved for a flat universe by taking
the gravitational and the cosmological constants as a function of time t. We
use Taylor's expansion of cosmological function, , up to the first
order of the time . The cosmological parameters are calculated and some
cosmological problems are discussed.Comment: 14 pages Latex, 5 figures, one table. arXiv admin note: text overlap
with arXiv:gr-qc/9805018 and arXiv:astro-ph/980526
Teleparallel Energy-Momentum Distribution of Spatially Homogeneous Rotating Spacetimes
The energy-momentum distribution of spatially homogeneous rotating spacetimes
in the context of teleparallel theory of gravity is investigated. For this
purpose, we use the teleparallel version of Moller prescription. It is found
that the components of energy-momentum density are finite and well-defined but
are different from General Relativity. However, the energy-momentum density
components become the same in both theories under certain assumptions. We also
analyse these quantities for some special solutions of the spatially
homogeneous rotating spacetimes.Comment: 12 pages, accepted for publication in Int. J. Theor. Phy
Pinning Susceptibility: The Effect Of Dilute, Quenched Disorder On Jamming
We study the effect of dilute pinning on the jamming transition. Pinning reduces the average contact number needed to jam unpinned particles and shifts the jamming threshold to lower densities, leading to a pinning susceptibility, χp. Our main results are that this susceptibility obeys scaling form and diverges in the thermodynamic limit as χp∝|ϕ−ϕ∞c|−γp where ϕ∞c is the jamming threshold in the absence of pins. Finite-size scaling arguments yield these values with associated statistical (systematic) errors γp=1.018±0.026(0.291) in d=2 and γp=1.534±0.120(0.822) in d=3. Logarithmic corrections raise the exponent in d=2 to close to the d=3 value, although the systematic errors are very large
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