33,222 research outputs found
Symmetry limit properties of a priori mixing amplitudes for non-leptonic and weak radiative decays of hyperons
We show that the so-called parity-conserving amplitudes predicted in the a
priori mixing scheme for non-leptonic and weak radiative decays of hyperons
vanish in the strong-flavor symmetry limit
Self-Dual Vortices in Abelian Higgs Models with Dielectric Function on the Noncommutative Plane
We show that Abelian Higgs Models with dielectric function defined on the
noncommutative plane enjoy self-dual vorticial solutions. By choosing a
particular form of the dielectric function, we provide a family of solutions
whose Higgs and magnetic fields interpolate between the profiles of the
noncommutative Nielsen-Olesen and Chern-Simons vortices. This is done both for
the usual model and for the semilocal model with a
doublet of complex scalar fields. The variety of known noncommutative self-dual
vortices which display a regular behaviour when the noncommutativity parameter
tends to zero results in this way considerably enlarged
State selection in the noisy stabilized Kuramoto-Sivashinsky equation
In this work, we study the 1D stabilized Kuramoto Sivashinsky equation with
additive uncorrelated stochastic noise. The Eckhaus stable band of the
deterministic equation collapses to a narrow region near the center of the
band. This is consistent with the behavior of the phase diffusion constants of
these states. Some connections to the phenomenon of state selection in driven
out of equilibrium systems are made.Comment: 8 pages, In version 3 we corrected minor/typo error
I-V curves and intergranular flux creep activation energy in the magnetic superconductor RuSr2GdCu2O8
A systematic study of I-V characteristic curves for RuSr2GdCu2O8 [Ru-(1212)]
is presented, with magnetic fields up to 3 T and 5 K<T<30 K, in the region of
the superconducting transition. The activation energy E_{a}(H,T) for flux line
depinning was determined by fitting the nonlinear region of the curves using
the flux creep model. E_{a}(H,T) was found to vary linearly with temperature,
while a power-law dependence on the magnetic field was observed up to H=0.1 T,
where an abrupt reduction in its decreasing rate occurs. The extrapolated
value, E_{a}(0,0)=50 meV, is twice the reported value for YBa2Cu3O7, but the
critical current density J_{C}(0,0)=70 A/cm2 is about one order of magnitude
lower. These results are explained as a consequence of the contribution of the
magnetization in the grains to the effective field at the intergranular links
and to a spin-flop transition of the Ru-sub-lattice.Comment: 4 pages, 3 figure
Adaptive Coordination of Distributed Energy Resources in Lossy Power Distribution Systems
This paper is concerned with the problem of coordinating a set of distributed
energy resources (DERs) in a lossy power distribution system to provide
frequency regulation services to a bulk power grid with the explicit
consideration of system losses. To this end, we formulate the problem as an
optimization problem, the objective of which is to minimize some cost function
subject to a set of constraints. The formulation requires knowledge of
incremental total system losses, which we approximate using the so-called loss
factors (LFs) that explicitly capture the impacts of both active and reactive
power injections on system losses. The LFs are estimated recursively using
power injection measurements; thus, they are adaptive to various phenomena that
impact the power system operation. Numerical simulation on a 33-bus
distribution test feeder validated the effectiveness of the proposed framework
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