65,095 research outputs found
Comments on the Monopole-Antimonopole Pair Solutions
Recently, the monopole-antimonopole pair and monopole-antimonopole chain
solutions are solved with internal space coordinate system of -winding
number greater than one. However, we notice that it is also possible to
solve these solutions numerically in terms of -winding number
instead. When , the exact asymptotic solutions at small and large
distances are parameterized by a single integer parameter . Here we once
again study the monopole-antimonopole pair solution of the SU(2)
Yang-Mills-Higgs theory which belongs to the topological trivial sector
numerically in its new form. This solution with -winding and
-winding number one is parameterized by at small and at
large .Comment: Two figures, 13 pages, to be sent for publicatio
Analysis of Combustion Instability in Liquid Fuel Rocket Motors
The development of a technique to be used in the solution of nonlinear velocity-sensitive combustion instability problems is described. The orthogonal collocation method was investigated. It found that the results are heavily dependent on the location of the collocation points and characteristics of the equations, so the method was rejected as unreliabile. The Galerkin method, which has proved to be very successful in analysis of the pressure sensitive combustion instability was found to work very well. It was found that the pressure wave forms exhibit a strong second harmonic distortion and a variety of behaviors are possible depending on the nature of the combustion process and the parametric values involved. A one-dimensional model provides further insight into the problem by allowing a comparison of Galerkin solutions with more exact finite-difference computations
Closed-loop structural stability for linear-quadratic optimal system
This paper contains an explicit parameterization of a subclass of linear constant gain feedback maps that will not destabilize an originally open-loop stable system. These results can then be used to obtain several new structural stability results for multi-input linear-quadratic feedback optimal designs
Inference and Optimization of Real Edges on Sparse Graphs - A Statistical Physics Perspective
Inference and optimization of real-value edge variables in sparse graphs are
studied using the Bethe approximation and replica method of statistical
physics. Equilibrium states of general energy functions involving a large set
of real edge-variables that interact at the network nodes are obtained in
various cases. When applied to the representative problem of network resource
allocation, efficient distributed algorithms are also devised. Scaling
properties with respect to the network connectivity and the resource
availability are found, and links to probabilistic Bayesian approximation
methods are established. Different cost measures are considered and algorithmic
solutions in the various cases are devised and examined numerically. Simulation
results are in full agreement with the theory.Comment: 21 pages, 10 figures, major changes: Sections IV to VII updated,
Figs. 1 to 3 replace
Reestimation of the production spectra of cosmic ray secondary positrons and electrons in the ISM
A detailed calculation of the production spectra of charged hadrons produced by interactions of cosmic rays in the interstellar medium is presented along with a thorough treatment of pion and muon decays. Newly parameterized inclusive cross sections of hadrons were used and exact kinematic limitations were taken into account. Single parametrized expressions for the production spectra of both secondary positrons and electrons in the energy range .1 to 100 GeV are presented. The results are compared with other authors' predictions. Equilibrium spectra using various models are also presented
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