7,790 research outputs found
An Alternative Method for Solving a Certain Class of Fractional Kinetic Equations
An alternative method for solving the fractional kinetic equations solved
earlier by Haubold and Mathai (2000) and Saxena et al. (2002, 2004a, 2004b) is
recently given by Saxena and Kalla (2007). This method can also be applied in
solving more general fractional kinetic equations than the ones solved by the
aforesaid authors. In view of the usefulness and importance of the kinetic
equation in certain physical problems governing reaction-diffusion in complex
systems and anomalous diffusion, the authors present an alternative simple
method for deriving the solution of the generalized forms of the fractional
kinetic equations solved by the aforesaid authors and Nonnenmacher and Metzler
(1995). The method depends on the use of the Riemann-Liouville fractional
calculus operators. It has been shown by the application of Riemann-Liouville
fractional integral operator and its interesting properties, that the solution
of the given fractional kinetic equation can be obtained in a straight-forward
manner. This method does not make use of the Laplace transform.Comment: 7 pages, LaTe
Domain Wall and Periodic Solutions of Coupled Asymmetric Double Well Models
Coupled asymmetric double well () one-dimensional
potentials arise in the context of first order phase transitions both in
condensed matter physics and field theory. Here we provide an exhaustive set of
exact periodic solutions of such a coupled asymmetric model in terms of
elliptic functions (domain wall arrays) and obtain single domain wall solutions
in specific limits. We also calculate the energy and interaction between
solitons for various solutions. Both topological (kink-like at ) and
nontopological (pulse-like for ) domain wall solutions are obtained.
We relate some of these solutions to domain walls in hydrogen bonded materials
and also in the field theory context. As a byproduct, we also obtain a new one
parameter family of kink solutions of the uncoupled asymmetric double well
model.Comment: 40 pages, no figure
Global satellite triangulation and trilateration for the National Geodetic Satellite Program (solutions WN 12, 14 and 16)
A multi-year study and analysis of data from satellites launched specifically for geodetic purposes and from other satellites useful in geodetic studies was conducted. The program of work included theoretical studies and analysis for the geometric determination of station positions derived from photographic observations of both passive and active satellites and from range observations. The current status of data analysis, processing and results are examined
Relative susceptibility of different cultivars of tomato to Rotylenchulus reniformis in relation to changes in phenolics
Mergers and Typical Black Hole Microstates
We use mergers of microstates to obtain the first smooth horizonless
microstate solutions corresponding to a BPS three-charge black hole with a
classically large horizon area. These microstates have very long throats, that
become infinite in the classical limit; nevertheless, their curvature is
everywhere small. Having a classically-infinite throat makes these microstates
very similar to the typical microstates of this black hole. A rough CFT
analysis confirms this intuition, and indicates a possible class of dual CFT
microstates.
We also analyze the properties and the merging of microstates corresponding
to zero-entropy BPS black holes and black rings. We find that these solutions
have the same size as the horizon size of their classical counterparts, and we
examine the changes of internal structure of these microstates during mergers.Comment: 49 pages, 5 figures. v2 references adde
Stability of nonlinear one-dimensional laser pulse solitons in a plasma
In a recent one-dimensional numerical fluid simulation study [Saxena et al.,
Phys. Plasmas 13,032309 (2006)], it was found that an instability is associated
with a special class of one-dimensional nonlinear solutions for modulated light
pulses coupled to electron plasma waves in a relativistic cold plasma model. It
is shown here that the instability can be understood on the basis of the
stimulated Raman scattering phenomenon and the occurrence of density bursts in
the trailing edge of the modulated structures are a manifestation of an
explosive instability arising from a nonlinear phase mixing mechanism.Comment: 17 pages, 7 figures, Published in Phys. Plasma
Domain Wall and Periodic Solutions of Coupled phi6 and Coupled phi6-phi4 Models
We obtain several higher order periodic solutions of a Coupled phi6 model in
terms of Lame polynomials of order one and two. These solutions are unusual in
the sense that while they are the solutions of the coupled problem, they are
not the solutions of the uncoupled problem. We also obtain exact solutions of
coupled phi6-phi4 models, both when the phi4 potential corresponds to a first
order (asymmetric double well) or a second order (symmetric double well)
transition.Comment: 17 pages, no figure
Viscoelastic Properties of Dynamically Asymmetric Binary Fluids Under Shear Flow
We study theoretically the viscoelastic properties of sheared binary fluids
that have strong dynamical asymmetry between the two components. The dynamical
asymmetry arises due to asymmetry between the viscoelastic stresses,
particularly the bulk stress. Our calculations are based on the two-fluid model
that incorporates the asymmetric stress distribution. We simulate the phase
separation process under an externally imposed shear and compare the asymmetric
case with the usual phase separation under a shear flow without viscoelastic
effects. We also simulate the behavior of phase separated stable morphologies
under applied shear and compute the stress relaxation.Comment: 10 pages text, 9 figure
Exact Solutions of the Two-Dimensional Discrete Nonlinear Schr\"odinger Equation with Saturable Nonlinearity
We show that the two-dimensional, nonlinear Schr\"odinger lattice with a
saturable nonlinearity admits periodic and pulse-like exact solutions. We
establish the general formalism for the stability considerations of these
solutions and give examples of stability diagrams. Finally, we show that the
effective Peierls-Nabarro barrier for the pulse-like soliton solution is zero
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