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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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Preface
Ignazio Licata
Full text: Acrobat
PDF (29 KB)
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2
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Symmetry, Conserved Charges, and Lax
Representations of Nonlinear Field Equations: A Unified Approach
C. J. Papachristou
Full text: Acrobat
PDF (129 KB)
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A
certain non-Noetherian connection between symmetry and integrability
properties of nonlinear field equations in conservation-law form is
studied. It is shown that the symmetry condition alone may lead, in a
rather straightforward way, to the construction of a Lax pair, a doubly
infinite set of (generally nonlocal) conservation laws, and a recursion
operator for symmetries. Applications include the chiral field equation and
the self-dual Yang-Mills equation.
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3
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Electroweak Standard Model at Finite Temperature
in Presence of A Bosonic Chemical Potential
Pena and C. Quimbay
Full text: Acrobat
PDF (168 KB)
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We
study the electroweak standard model at finite temperature in presence of a
bosonic chemical potential associated with the conserved electromagnetic
current. To preserve the thermodynamic equilibrium of the system, the
thermal medium is neutralized by the introduction of four background
charges related to the four gauge bosons of this model. Using the
mean-field approximation, in the high temperature limit, we find that there
exists a difference between the effective mass of the spatial and temporal
components of the W boson. A W boson condensation induced via the
background charges allows to vanish this difference.
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4
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Electric Dipole Moment and Neutrino Mixing due to
Planck Scale Effects
Bipin Singh Koranga
Full text: Acrobat
PDF (97 KB)
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In
this paper, we consider the effect of Planck scale operators on electric
dipole moment of the electron $de$. The electric dipole moment of the
electron, $de$ is known to vanish up to three loops in the standard model
with massless neutrinos We consider the Planck scale operator on neutrino
mixing. We assume that the neutrino masses and mixing arise through physics
at a scale intermediate between Planck scale and the electroweak breaking
scale. We also assume, that just above the electroweak breaking scale
neutrino mass are nearly degenerate and the mixing is bi-maximal. Quantum
gravity (Planck scale) effects lead to an effective SU(2)_{L} U(1)
invariant dimension-5 Lagrangian symmetry involving Standard Model. On
electroweak symmetry breaking, this operator gives rise to correction to
the neutrino masses and mixings these additional terms can be considered as
perturbation to the bimaximal neutrino mass matrix We assume that the
gravitational interaction is flavour blind and we study the neutrino mixing
and electric dipole moment due to the Planck scale effects.
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5
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Spinless Relativistic Particle in the Presence of
A Minimal Length
M. Merad, F. Zeroual, and H. Benzair
Full text: Acrobat
PDF (151 KB)
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In this paper, we propose to
study the (1+1)-dimensional Klein-Gordon equation in the presence of a
minimal length by two approaches: a method direct in the position space
representation and a path integral formalism in energy-momentum space,
where a particle is subjected to a mixing of \ linear vector plus scalar
potentials. For a first method, a suitable approximation technique of a non-relativistic
quantum mechanics has been applied and the shifts of the relativistic
energy levels is determined. For a second method, the Green function is
obtained, the energy spectrum together with the normalized wave functions
of the bound states are deduced \ and the limiting case is considered. The
results of both methods are compared and we find the same dominant
quantities to order 1 on parameter of deformation.
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6
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Astrophysical Chaotic Gun Effect
Gheorghe Dumitrescu
Full text: Acrobat
PDF (185 KB)
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We
propose a kinetic equation for a special kind of acceleration: chaotic gun
effect. Then we infer a distribution function which can depict the
instability condition. With this distribution function we derive the power
spectrum of the synchrotron emission and we prove the power law form of the
power spectrum. We show that the spectral index of the emission spectrum is
related to the spectral index of the number of the charged particles in the
beam. Our numeric simulations show that the spectrum has a break at a
frequency threshold where the chaotic acceleration becomes efficient.
Assuming this threshold to the set on of the efficient chaotic gun effect
we estimate the magnetic strength .Our paper advocates an electromagnetic
process able to accelerate charged particles to high energies starting from
low energies. Assuming the high-energy particles spectra of Mkn 501 to be
produced by the synchrotron emission during chaotic gun effect we estimate
some parameters of the source.
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7
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Chaos in Quantum Chromodynamics and the Hadron
Spectrum
Ervin Goldfain
Full text: Acrobat
PDF (114 KB)
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We
present analytic evidence that the distribution of hadron masses follows from
the universal transition to chaos in non-equilibrium field theory. It is
shown that meson and baryon spectra obey a scaling hierarchy with critical
exponents ordered in natural progression. Numerical predictions are found
to be in close agreement with experimental data.
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8
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Towards The Determination of Properties of the
Unconventional Josephson Junction Made by Putting Non-Superconducting Strip
on the Top of Superconducting Strip
Krzysztof Pomorski and Przemyslaw Prokopow
Full text: Acrobat
PDF (1,652 KB)
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We
present the theoretical approach to study the unconventional Josephson
junction (uJJ) made by putting the non-superconducting strip on the top of
superconducting strip. We work in the framework of the Ginzburg-Landau,
Bogoliubov de Gennes and Usadel equations. Then we solve the non-linear partial
differential equations numerically for few simple cases. We review the
similarities and new aspects of uJJ with currently known Josephson
junctions. Basing on the obtained results and current knowledge on
Josephson junctions we point the future perspectives of the research on
uJJs.
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9
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An Interruption in the
Highway: New Approach to Modeling the Car-Traffic
Amin Rezaeezadeh
Full text: Acrobat
PDF (285 KB)
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A
very common phenomena in car-traffic system is investigated in this
article. The problem is one-dimensional. We try to find the wave equation
of the traffic and then, we'll talk more about the simulation of the system
using Matlab7.6.
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10
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A generalization of the
Three-Dimensional Harmonic Oscillator Basis for Wave Functions with
Non-Gaussian Asymptotic Behavior
Maurizio De Sanctis
Full text: Acrobat
PDF (102 KB)
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Starting
from the standard harmonic oscillator basis, we construct new sets of orthonormal
wave functions with non-Gaussian
asymptotic spatial dependence. These new wave functions can be used to
study at numerical level two-body bound systems like mesons and baryons
within quark-diquark models. Generalized hyperradial functions for
three-quark models are also studied.
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11
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Exactly solved potentials
generated from the Manning-Rosen potential using extended transformation
method
S. A. S. Ahmed and L. Buragohain
Full text: Acrobat
PDF (113 KB)
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Generation of exactly
solvable quantum systems in non-relativistic quantum mechanics from an
already analytically solved quantum system is presented using extended
transformation method. The bound state quantized energy spectra and the
corresponding wavefunctions of the generated potentials are obtained. It is
also shown that eigenfunctions of the new quantum systems can easily be
normalized.
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12
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On the Bound-State Spectrum
of A Nonrelativistic Particle in the Background of A Short-Ranged Linear
Potential
L.B. Castro and A.S. de Castro
Full text: Acrobat
PDF (118 KB)
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The nonrelativistic problem
of a particle immersed in a triangular potential well, set forth by N. A.
Rao and B. A. Kagali, is revised. It is shown that these researchers
misunderstood the full meaning of the potential and obtained a wrong
quantization condition. By exploring the space inversion symmetry, this
work presents the correct solution to this problem with potential
applications in electronics in a simple and transparent way.
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13
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Relativistic Spin Operator
with Observers in Motion
J. P. Singh
Full text: Acrobat
PDF (156 KB)
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We obtain transformation
equations for the Bell basis states under an arbitrary Lorentz boost and
compute the expectation values of the relativistic center of mass spin
operator under each of these boosted states. We also obtain expectation
values for spin projections along the axes.
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14
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Statistical Mechanics of
Classical N-Particle System of
Galaxies in the Expanding Universe
Farooq Ahmad and Abdul Wahid
Full text: Acrobat
PDF (101 KB)
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For the distribution of
classical non-interacting particles we use Maxwell-Boltzmann's statistics.
However, this statistics is not workable for classical interacting
particles (galaxies). We attempt to modify the Maxwell-Boltzmann's
statistics by incorporating gravitational interaction term in it. The number
of ways in which N-particles can have pair interaction due to gravitational
interaction is obtained. With the help of entropy maximization we derive
the analytical expression for occupation number. Using the modified statistics
we obtain the general expressions for different thermodynamical quantities
and attempt to derive general distribution function for gravitating
particles (galaxies).
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15
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On the Noncommutative Space-time Bianchi I
Universe and Particles Pair Creation Process
N. Mebarki, L. Khodja and S. Zaim
Full text: Acrobat
PDF (155 KB)
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Using
an approach of modified Euler-Lagrange field equations obtained from an
invariant action under infinitesimal modified general coordinates, local Lorentz
and U_{\ast }(1) gauge transformations together with the corresponding
Seiberg-Witten maps of the dynamical fields, a generalized Dirac equation
in the presence of a constant electric field and a noncommutative
cosmological anisotropic Bianchi I universe is derived and the particles
pair creation process is studied.
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16
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Cylindrically Symmetric Inhomogeneous String
Cosmological Models of Perfect Fluid Distribution with Electromagnetic
Fields
Anirudh Pradhan and Rekha Singh
Full text: Acrobat
PDF (139 KB)
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Two
new cylindrically symmetric inhomogeneous string cosmological models are investigated
in presence of magnetic field. We have assumed that F_{12} is the only
non-vanishing component of electromagnetic field tensor F_{ij}. The
Maxwell's equations show that F_{12} is the function of $x$ alone whereas the
magnetic permeability \bar{\mu} is the function of x and t both. To get the
deterministic solution, it has been assumed that the metric coefficients
are separable in the form as A = f(x) \ell(t), B = g(x) k(t), C = g(x)
\nu(t). Also, the Einstein field equations have been solved with string
source in which magnetic field is absent. Some physical and geometric aspects
of the models in presence and absence of magnetic field are discussed.
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17
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Some LRS Bianchi Type-II String-Dust Cosmological
Models in General Relativity
Hassan Amirhashchi and Hishamuddin Zainuddin
Full text: Acrobat
PDF (98 KB)
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Some LRS Bianchi type-II
string- dust cosmological models are investigated in which the expansion
(\theta) is assumed to be proportional to the shear (\sigma). To obtain
exact solutions, the Einstein's field equations have been solved for two
cases (i) Reddy string and (ii) Nambu string. The physical and geometrical
behaviour of these models are discussed.
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18
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Relativistic Particle Motion and Radiation
Reaction in Electrodynamics
Richard T. Hammond
Full text: Acrobat
PDF (423 KB)
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The
problem of radiation reaction and the self force is the oldest unsolved
mystery in physics. At times it is considered a minor issue, a malefactor
born of classical electrodynamics, while at other times it is public enemy
number one, a major inconsistency and unsolved problem. This work derives
some of the basic and most important results while reviewing some of the
other known approaches to the problem. Some historical notes are given, and
yet another approach is discussed that accounts for radiation reaction
without the unphysical behavior that plagues so many theories.
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19
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The Fundamental Equations of Point, Fluid and Wave Dynamics in the De
Sitter-Fantappie-Arcidiacono Projective Relativity Theory
Leonardo Chiatti
Full text: Acrobat
PDF (186 KB)
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A
review is presented of the fundamental equations of point, perfect incompressible
fluid and wave dynamics in the Fantappie-Arcidiacono theory of projective
relativity, also known as ``De Sitter relativity''. Compared to the
original works, some deductions have been simplified and the physical
meaning of the equations has been analyzed in greater depth.
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20
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Geodesics of Deformed Relativity in Five
Dimensions
Fabio Cardone, Alessio Marrani and Roberto Mignani
Full text: Acrobat
PDF (471 KB)
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In
a previous paper, we discussed the Killing symmetries of the Kaluza-Klein-like
scheme known as Deformed Relativity in five dimensions (DR5), based on a
five-dimensional Riemannian space \mathcal{\Re }_{5} in which the
four-dimensional space-time metric is deformed ({i.e.} it depends on the
energy) and energy plays the role of the fifth dimension. In the present
paper, we carry on the investigation of the main mathematical aspects of
DR5 by studying the geodesic motions in \mathcal{\Re }_{5}. In particular,
we consider the case of physical relevance in which the metric coefficients
are power functions of the energy (Power Ansatz). The geodesic equations
are solved explicitly for all the twelve 5-d. metrics obtained as solutions
of the vacuum Einstein equations, and in particular for those describing
the four fundamental interactions. It is also shown that it is possible,
from the geodesic motion related to one of these Power-Ansatz solutions, to
get a time-energy uncertainty relation of the Heisenberg type.
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21
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Theory of Dirac Equation without Negative Energie
E. Trubenbacher
Full text: Acrobat
PDF (205 KB)
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It
is shown that the well-known Hermitean operator 'sign of frequency' for the
free Dirac equation has the physical meaning of 'sign of charge'. Since the
kinetic energy of a free particle should not depend on its charge state,
this identification requires a modification of the traditional quantum
mechanical 4-momentum operators when used with Dirac spinors. Due to the
new 4-momentum operators the Dirac equation has no negative energy
solutions\textbf{ }and the complex of problems associated with the latter
disappears from the theory. The quantum number 'sign of charge' rigorously
defines electronic and positronic plane waves. Second quantization of the
free Dirac equation does not need the traditional amendments required by
the negative energy values. As an example for the application of the theory
the relativistic hydrogen ground state wave function is analyzed with
respect to the quantum number 'sign of charge'. Since the operator 'sign of
charge' does not commute with the Coulomb potential the wave function is
only an approximate eigenfunction of
the operator 'sign of charge'. It is shown how one can construct
'effective potentials' that commute with the operator 'sign of charge' and
thus are able to produce eigenfunctions of charge when used in the Dirac
equation.
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