5,403 research outputs found
Grid service orchestration using the Business Process Execution Language (BPEL)
Modern scientific applications often need to be distributed across grids. Increasingly
applications rely on services, such as job submission, data transfer or data
portal services. We refer to such services as grid services. While the invocation
of grid services could be hard coded in theory, scientific users want to orchestrate
service invocations more flexibly. In enterprise applications, the orchestration of
web services is achieved using emerging orchestration standards, most notably
the Business Process Execution Language (BPEL). We describe our experience
in orchestrating scientific workflows using BPEL. We have gained this experience
during an extensive case study that orchestrates grid services for the automation of
a polymorph prediction application
Effects of stoichiometry, purity, etching and distilling on resistance of MgB2 pellets and wire segments
We present a study of the effects of non-stoichiometry, boron purity, wire
diameter and post-synthesis treatment (etching and Mg distilling) on the
temperature dependent resistance and resistivity of sintered MgB2 pellets and
wire segments. Whereas the residual resistivity ratio (RRR) varies between RRR
\~ 4 to RRR > 20 for different boron purity, it is only moderately affected by
non-stoichiometry (from 20% Mg deficiency to 20% Mg excess) and is apparently
independent of wire diameter and presence of Mg metal traces on the wire
surface. The obtained set of data indicates that RRR values in excess of 20 and
residual resistivities as low as rho{0} ~ 0.4 mu Ohm cm are intrinsic material
properties of high purity MgB2
Unparticle Physics in the Moller Scattering
We investigate the virtual effects of vector unparticles in the Moller
scattering. We derive the analytic expression for scattering amplitudes with
unpolarized beams. We obtain 95% confidence level limits on the unparticle
couplings and with integrated luminosity of
and and 500 GeV energies. We show
that limits on are more sensitive than .Comment: 10 pages, 5 figures, 4 table
All-optical switching in metamaterial with high structural symmetry
We argue the possibility of realization of a polarization insensitive
all-optical switching in a planar metamaterial composed of a 4-fold periodic
array of two concentric metal rings placed on a substrate of nonlinear
material. It is demonstrated that a switching may be achieved between
essentially different values of transmission near the resonant frequency of the
high-quality-factor Fano-shape trapped-mode excitation.Comment: 7 pages, 3 figure
On the Rigorous Derivation of the 3D Cubic Nonlinear Schr\"odinger Equation with A Quadratic Trap
We consider the dynamics of the 3D N-body Schr\"{o}dinger equation in the
presence of a quadratic trap. We assume the pair interaction potential is
N^{3{\beta}-1}V(N^{{\beta}}x). We justify the mean-field approximation and
offer a rigorous derivation of the 3D cubic NLS with a quadratic trap. We
establish the space-time bound conjectured by Klainerman and Machedon [30] for
{\beta} in (0,2/7] by adapting and simplifying an argument in Chen and
Pavlovi\'c [7] which solves the problem for {\beta} in (0,1/4) in the absence
of a trap.Comment: Revised according to the referee report. Accepted to appear in
Archive for Rational Mechanics and Analysi
New supersymmetric solutions of N=2, D=5 gauged supergravity with hyperscalars
We construct new supersymmetric solutions, including AdS bubbles, in an N=2
truncation of five-dimensional N=8 gauged supergravity. This particular
truncation is given by N=2 gauged supergravity coupled to two vector multiples
and three incomplete hypermultiplets, and was originally investigated in the
context of obtaining regular AdS bubble geometries with multiple active
R-charges. We focus on cohomogeneity-one solutions corresponding to objects
with two equal angular momenta and up to three independent R-charges.
Curiously, we find a new set of zero and negative mass solitons asymptotic to
AdS_5/Z_k, for k \ge 3, which are everywhere regular without closed timelike
curves.Comment: Latex 3 times, 42 page
Some Issues in a Gauge Model of Unparticles
We address in a recent gauge model of unparticles the issues that are
important for consistency of a gauge theory, i.e., unitarity and Ward identity
of physical amplitudes. We find that non-integrable singularities arise in
physical quantities like cross section and decay rate from gauge interactions
of unparticles. We also show that Ward identity is violated due to the lack of
a dispersion relation for charged unparticles although the Ward-Takahashi
identity for general Green functions is incorporated in the model. A previous
observation that the unparticle's (with scaling dimension d) contribution to
the gauge boson self-energy is a factor (2-d) of the particle's has been
extended to the Green function of triple gauge bosons. This (2-d) rule may be
generally true for any point Green functions of gauge bosons. This implies that
the model would be trivial even as one that mimics certain dynamical effects on
gauge bosons in which unparticles serve as an interpolating field.Comment: v1:16 pages, 3 figures. v2: some clarifications made and presentation
improved, calculation and conclusion not modified; refs added and updated.
Version to appear in EPJ
Magnetic flux dynamics in critical state of one-dimensional discrete superconductor
We give a theoretical description of avalanche-like dynamics of magnetic flux
in the critical state of "hard" type-II superconductors using a model of a
one-dimensional multijunction SQUID that well reproduces the main magnetic
properties of these objects. We show that the system under consideration
demonstrates the self-organized criticality. The avalanches of vortices
manifest themselves as jumps of the total magnetic flux in the sample. The
sizes of these jumps have a power-law distribution. Our results are in
qualitative agreement with experiments.Comment: 7 pages, 5 figure
Continuous-variable Werner state: separability, nonlocality, squeezing and teleportation
We investigate the separability, nonlocality and squeezing of
continuous-variable analogue of the Werner state: a mixture of pure two-mode
squeezed vacuum state with local thermal radiations. Utilizing this Werner
state, coherent-state teleportation in Braunstein-Kimble setup is discussed.Comment: 7 pages, 4 figure
Enhanced local-type inflationary trispectrum from a non-vacuum initial state
We compute the primordial trispectrum for curvature perturbations produced
during cosmic inflation in models with standard kinetic terms, when the initial
quantum state is not necessarily the vacuum state. The presence of initial
perturbations enhances the trispectrum amplitude for configuration in which one
of the momenta, say , is much smaller than the others, . For those squeezed configurations the trispectrum acquires the
so-called local form, with a scale dependent amplitude that can get values of
order . This amplitude can be larger than the
prediction of the so-called Maldacena consistency relation by a factor ,
and can reach the sensitivity of forthcoming observations, even for
single-field inflationary models.Comment: 11 pages, 1 figure. References added, typos corrected, minor change
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