The Influence of Strong Interaction on the Pionium Wave Functions at Small Distances

The influence of strong $\pi^+\pi^-$ 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 $\pi^+\pi^-$ atom production in nS-state remains the same as in case of pure Coulomb $\pi^+\pi^-$ interactionComment: 4 pages, 2 figure

The Influence of Strong Interaction on the Pionium Wave Functions at Small Distances

The influence of strong $\pi^+\pi^-$ 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 $\pi^+\pi^-$ interactio

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

Monitoring of Engineering Applications

This paper presents a license monitoring system implemented at CERN in the Computing for Engineering (CE) group of the Information Technology (IT) division. The system gathers statistics on the use of the different software products supported by the group on both Windows and Unix platforms. The web is used for all aspects of the project; data presentation and associated interfaces. The system is completely automated. Manual intervention is required only when there are new products to be monitored. Certain technical details of this work have been reported elsewhere

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

Mathematical Modeling of Boson-Fermion Stars in the Generalized Scalar-Tensor Theories of Gravity

A model of static boson-fermion star with spherical symmetry based on the scalar-tensor theory of gravity with massive dilaton field is investigated numerically. Since the radius of star is \textit{a priori} an unknown quantity, the corresponding boundary value problem (BVP) is treated as a nonlinear spectral problem with a free internal boundary. The Continuous Analogue of Newton Method (CANM) for solving this problem is applied. Information about basic geometric functions and the functions describing the matter fields, which build the star is obtained. In a physical point of view the main result is that the structure and properties of the star in presence of massive dilaton field depend essentially both of its fermionic and bosonic components.Comment: 16 pages, amstex, 5 figures, changed conten