120 research outputs found
The Influence of Strong Interaction on the Pionium Wave Functions at Small Distances
The influence of strong interaction of the behaviour of pionium
nS-state wave functions at small distance are investigated both analytically
(perturbatively) and so numerically. It is shown that in the whole the
accounting of strong interaction results in multiplying of pure Coulomb pionium
wave functions by some function practically independent on value of principal
quantum number n. Due to this reason the n-independence of probability of
atom production in nS-state remains the same as in case of pure
Coulomb interactionComment: 4 pages, 2 figure
The Influence of Strong Interaction on the Pionium Wave Functions at Small Distances
The influence of strong interaction of the behaviour of pionium nS-state wave functions at small distance are investigated both analytically (perturbatively) and so numerically. It is shown that in the whole the accounting of strong interaction results in multiplying of pure Coulomb pionium wave functions by some function practically independent on value of principal quantum number n. Due to this reason the n-independence of probability of Coulomb interactio
Parallelizing multiple precision Taylor series method for integrating the Lorenz system
A hybrid MPI+OpenMP strategy for parallelizing multiple precision Taylor
series method is proposed, realized and tested. To parallelize the algorithm we
combine MPI and OpenMP parallel technologies together with GMP library (GNU
miltiple precision libary) and the tiny MPIGMP library. The details of the
parallelization are explained on the paradigmatic model of the Lorenz system.
We succeed to obtain a correct reference solution in the rather long time
interval - [0,7000]. The solution is verified by comparing the results for
2700-th order Taylor series method and precision of ~ 3374 decimal digits, and
those with 2800-th order and precision of ~ 3510 decimal digits. With 192 CPU
cores in Nestum cluster, Sofia, Bulgaria, the 2800-th order computation was ~
145 hours with speedup ~ 105.Comment: arXiv admin note: text overlap with arXiv:1908.0930
Influence of Josephson current second harmonic on stability of magnetic flux in long junctions
We study the long Josephson junction (LJJ) model which takes into account the
second harmonic of the Fourier expansion of Josephson current. The dependence
of the static magnetic flux distributions on parameters of the model are
investigated numerically. Stability of the static solutions is checked by the
sign of the smallest eigenvalue of the associated Sturm-Liouville problem. New
solutions which do not exist in the traditional model, have been found.
Investigation of the influence of second harmonic on the stability of magnetic
flux distributions for main solutions is performed.Comment: 4 pages, 6 figures, to be published in Proc. of Dubna-Nano2010, July
5-10, 2010, Russi
Lie point symmetries of differential--difference equations
We present an algorithm for determining the Lie point symmetries of
differential equations on fixed non transforming lattices, i.e. equations
involving both continuous and discrete independent variables. The symmetries of
a specific integrable discretization of the Krichever-Novikov equation, the
Toda lattice and Toda field theory are presented as examples of the general
method.Comment: 17 pages, 1 figur
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