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Number
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Articles Title
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Abstract
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1
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Foreword
Ignazio Licata
Full text: Acrobat
PDF (30 KB)
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2
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Equivalence Principle and Field
Quantization in Curved Spacetime
H. Kleinert
Full text: Acrobat
PDF (93 KB)
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To
comply with the equivalence principle, fields in curved spacetime
can be quantized only in the neighborhood of each point, where one can
construct a freely falling Minkowski frame with
zero curvature. In each such frame, the geometric forces of gravity can be
replaced by a selfinteracting spin-2 field, as
proposed by Feynman in 1962. At a fixed distance $R$ from a black hole, the
vacuum in each freely falling volume element acts like a thermal bath of
all particles with Unruh temperature T_U=\hbar
GM/2\pi c R^2. At the horizon R=2GM/c^2, the falling vacua
show the Hawking temperature T_H=\hbar c^3/8\pi GMk_B
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3
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New Seiberg-Witten
Fields Maps Through Weyl Symmetrization
and the Pure Geometric Extension of The Standard Model
N. Mebarki; F. Khelili and O. Benabbes
Full text: Acrobat
PDF (183 KB)
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A
unified description of a symmetrized and anti-symmetrized Moyal star product
of the noncommutative infinitesimal gauge
transformations is presented and the corresponding Seiberg-Witten
maps are derived. Moreover, the noncommutative
covariant derivative, field strength tensor as well as gauge
transformations are shown to be consistently constructed not on the enveloping
but on the Lie and/or Poisson algebra. As an application, a pure geometric
extension of the standard model is shown explicitly.
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4
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A Method for Constructing a Lax Pair for the Ernst
Equation
C. J. Papachristou and B. Kent Harrison
Full text: Acrobat
PDF (118 KB)
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A
systematic construction of a Lax pair and an infinite set of conservation
laws for the Ernst equation is described. The
matrix form of this equation is rewritten as a differential ideal of (2,R)-valued differential forms, and its symmetry
condition is expressed as an exterior equation which is linear in the
symmetry characteristic and has the form of a conservation law. By means of
a recursive process, an infinite collection of such laws is then obtained,
and the conserved ``charges'' are used to derive a linear exterior equation
whose components constitute a Lax pair.
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5
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Plane Symmetric Viscous Fluid Universe in Lyra Geometry
Pratima Singh and Pawan Kumar
Rai
Full text: Acrobat
PDF (154 KB)
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A new class of
plane-symmetric homogeneous cosmological models for viscous fluid
distribution is obtained in the context of Lyra's
geometry. We have obtained two types of solutions by considering the uniform
as well as time dependent displacement field. To get the deterministic
solutions of Einstein's modified field equations, the free gravitational
field is assumed to be of type D which is of the next order in the
hierarchy of Petrov classification. It has been found
that the displacement vector $\beta$ behaves like cosmological term \Lambda
in the normal gauge treatment and the solutions are consistent with the
observations. The displacement vector \beta(t) affects
entropy. Some physical and geometric properties of the models are
discussed.
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6
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Some Bianchi Type I Cosmological Models of the
Universe for Viscous Fluid Distribution in Lyra
Geometry
Ravi Prakash Singh and Lallan Yadav
Full text: Acrobat
PDF (147 KB)
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Some
Bianchi type I cosmological models of the universe with time dependent
gauge function $\beta$ for viscous fluid distribution within the framework
of Lyra geometry are investigated in which the expansion
is considered only in two dimensions i.e. one of the Hubble parameter (H_{1} = \frac{\dot{A}}{A}) is
zero. To get the deterministic solutions of Einstein's modified field
equations, the viscosity coefficient of bulk viscous fluid is assumed to be
a power function of mass density and the coefficient of shear viscosity is considered
as constant in first case whereas in other case it is taken as proportional
to scale of expansion in the model. It has been found that the displacement
vector \beta(t) behaves like cosmological term
\Lambda in the normal gauge treatment and the solutions are consistent with
the observations. Solution in absence of shear viscosity is also obtained.
The displacement vector \beta(t) affects entropy.
Some physical and geometrical properties of the models are discussed.
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7
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Geometrical Behaviuors
of LRS Bianchi Type-I Cosmological Model
Hassan Amirhashchi, Hishamuddin Zainuddin and Hamid Nil Saz Dezfouli
Full text: Acrobat
PDF (84 KB)
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By
using Einstein's theory of general relativity some properties of spatially
homogeneous locally rotationally symmetric (LRS) Bianchi type-I space-time
are investigated in empty space. The concept of Riemannian curvature
tensor, Ricci tensor and Ricci scalar has been used to discuss the
geometrical behavior of the space-time. It is shown that, LRS Bianchi
type-I has always flat geometry in empty space. Also we have shown that the
vacuum model does not have singularity when time goes to zero.
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8
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Bianchi Type V Bulk Viscous Cosmological Models
with Time Dependent Lambda Λ Term
J. P. Singh and P. S. Baghel
Full text: Acrobat
PDF (119 KB)
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Spatially
homogeneous and anisotropic Bianchi type V space-time with bulk viscous
fluid source and time-dependent cosmological term are considered.
Cosmological models have been obtained by assuming a variation law for the
Hubble parameter which yields a constant value of deceleration parameter.
Physical and kinematical parameters of the models are discussed. The models
are found to be compatible with the results of cosmological observations.
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9
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Corrections to massive
neutrino masses, caused by vacuum polarisation in
strong Coulomb field of daughter nuclei in weak decays of heavy ions
N. Ivanov,
P. Kienle, E. L. Kryshen, and M. Pitschmann
Full text: Acrobat
PDF (159 KB)
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We
calculate corrections to masses of massive neutrino mass--eigenstates,
caused by vacuum polarization in the strong
Coulomb fields of daughter heavy nuclei in the K--shell electron capture decays (EC) and positron
(\beta^+) decays of highly ionized
heavy ions, investigated experimentally at GSI in Darmstadt. Some applications of the
obtained results are discussed.
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10
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Neutrino Mass Differences and
Nonunitarity of Neutrino Mixing Matrix from
Interfering Recoil Ions
H. Kleinert and P. Kienle
Full text: Acrobat
PDF (222 KB)
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We
show that the recent observation of the time modulation of two-body weak
decays of heavy ions reveals the mass content of the electron neutrinos via interference
patterns in the recoiling ion wave function. From the modulation period we
derive the difference of the square masses \Delta m^2\approx 22.5\times 10^{-5}$\,eV${}^2, which is
about 2.8 times larger than that derived from a combined analysis of KamLAND and solar neutrino oscillation experiments. It
is, however, compatible with a data regime to which the KamLAND
analysis attributes a smaller probability. The experimental results displayed
in Fig.~1 imply that the neutrino mixing matrix
violates unitarity by about 10\%.
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11
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Bifurcations of
fractional-order diffusionless Lorenz system
Kehui Sun and J. C. Sprott
Full text: Acrobat
PDF (1,886 KB)
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Using the
predictor-corrector scheme, the fractional-order diffusionless
Lorenz system is investigated numerically. The effective chaotic range of the
fractional-order diffusionless system for
variation of the single control parameter is determined. The route to chaos
is by period-doubling bifurcation in this fractional-order system, and some
typical bifurcations are observed, such as the flip bifurcation, the
tangent bifurcation, an interior crisis bifurcation, and transient chaos.
The results show that the fractional-order diffusionless
Lorenz system has complex dynamics with interesting characteristics.
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12
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Underdeterminacy and redundance in Maxwell’s
Equations
Peter Enders
Full text: Acrobat
PDF (225 KB)
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Maxwell's (1864) original
equations are redundant in their description of charge conservation. In the
nowadays used, 'rationalized' Maxwell equations, this redundancy is removed
through omitting the continuity equation. Alternatively, one can Helmholtz
decompose the original set and omit instead the longitudinal part of the
flux law. This provides at once a natural description of the transversality of free electromagnetic waves and paves the
way to eliminate the gauge freedom. Poynting's
inclusion of the longitudinal field components in his theorem represents an
additional assumption to the Maxwell equations. Further, exploiting the
concept of Newtonian and Laplacian vector fields,
the role of the static longitudinal component of the vector potential being
\emph{not} determined by Maxwell's equations, but
important in quantum mechanics (Aharonov-Bohm
effect) is elucidated. Finally, extending Messiah's (1999) description of a
gauge invariant canonical momentum, a manifest gauge invariant canonical formulation
of Maxwell's theory \emph{without} imposing any contraints or auxiliary conditions will be proposed as
input for Dirac's (1949) approach to special-relativistic dynamics.
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13
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The Proton as A Kerr-Newman
Black Hole
Robert L. Oldershaw
Full text: Acrobat
PDF (72 KB)
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The general equation
governing the mass, spin and angular momentum of a Kerr-Newman black hole
applies equally well to a proton when the gravitational coupling constant
predicted by a discrete fractal paradigm is used in the equation, along
with the standard mass, spin and angular momentum of the proton.
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14
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Self-Interacting Scalar Field
and Galactic Dark Halos
M. R. Bordbar
and N. Riazi
Full text: Acrobat
PDF (217 KB)
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We construct dark halo
models which are supported by a self-interacting scalar field. The
possibility that the energy density of such a field which could produce
dark matter and dark energy inside and outside of the galactic dark halos
is explored.
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15
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Path Integral Quantization of The Electromagnetic
Field Coupled to A Spinor
Walaa. I. Eshraim
and Nasser. I. Farahat
Full text: Acrobat
PDF (94 KB)
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The
Hamilton-Jacobi approach is applied to the electromagnetic field coupled to
a spinor. The integrability
conditions are investigated and the path integral quantization is performed
using the action given by Hamilton-Jacobi approach.
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16
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Neutrino Mixing and Cosmological Constant above
GUT Scale
Bipin Singh Koranga
Full text: Acrobat
PDF (99 KB)
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Neutrino mixing lead to a non zero contribution to the cosmological constant.
We consider non renormalization $1/M_{x}$
interaction term as a perturbation of the neutrino mass matrix. We find
that for the degenerate neutrino mass spectrum. We assume that the neutrino
masses and mixing arise through physics at a scale intermediate between
Planck Scale and the electroweak scale. We also assume, above the
electroweak breaking scale, neutrino masses are nearly degenerate and their
mixing is bimaximal. Quantum gravitational
(Planck scale) effects lead to an effective $SU(2)_{L}\times U(10$
invariant dimension-5 Lagrangian involving
neutrino and Higgs fields, which gives rise to additional terms in neutrino
mass matrix. There additional term can be considered to be perturbation of
the GUT scale bi-maximal neutrino mass matrix. We assume that the
gravitational interaction is flavour
blind and we study the neutrino mixing and cosmological constant due to
physics above the GUT scale.
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17
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The Restricted Three Body Problem with Quadratic
Drag
Mayer Humi
Full text: Acrobat
PDF (207 KB)
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When
an asteroid, space-craft or another small object in the solar system is in
the vicinity of a planet it is subjected to the gravitational forces of the
Sun, the planet, the drag forces due to the solar wind and (possibly) the
planet upper atmosphere. To determine the object trajectory we consider
this problem within the context of the restricted three body problem in
three dimensions with quadratic drag. In this setting we linearize the equations of motion of the object and
cast them in a coordinate system with respect to the secondary (planet)
which is assumed to be in a general Keplerian
orbit around the primary (Sun). We then reduce them, to a simple system of
three second order linear differential equations. These equations can be
considered to be a generalization of Hill's equations to general Keplerian orbits (of the secondary) with the addition
of quadratic drag force acting on the third object in the system. We derive
also "approximate conservation laws" in three dimensions which
represent a generalization of Jacobi's integral in two dimensions and
consider some special cases.
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