The Regular Truncation Scheme of the BBGKY Hierarchy Equations for the Multi-Component Weakly Non-Ideal Plasma

A regular truncation scheme in which the divergencies characteristic of the Debye truncation are removed by taking into account the shall-range correlations. As a result, the two radii of screening the Debye radius D and √2 D appear in plasma which is not symmetrical as to its particle charges. The criterion of the applicability of this approach relates the plasma parameter to the potential depth of unlike-charged particles interaction.     

Chamber behavior of double Hurwitz numbers in genus 0

We study double Hurwitz numbers in genus zero counting the number of covers CP¹→CP¹ with two branching points with a given branching behavior. By the recent result due to Goulden, Jackson and Vakil, these numbers are piecewise polynomials in the multiplicities of the preimages of the branching points. We describe the partition of the parameter space into polynomiality domains, called chambers, and provide an expression for the difference of two such polynomials for two neighboring chambers. Besides, we provide an explicit formula for the polynomial in a certain chamber called totally negative, which enables us to calculate double Hurwitz numbers in any given chamber as the polynomial for the totally negative chamber plus the sum of the differences between the neighboring polynomials along a path connecting the totally negative chamber with the given one.     

On investigation of high Tc superconductors with Electron Paramagnetic Resonance spectrometers

Following the discovery of high T_c superconductors, many researchers have applied EPR spectrometers to investigate their properties using the regular instructions to operate the spectrometer. As no substantial information was obtained it was soon practically abandoned. Investigations performed recently with the EPR technique, using a different operating method than the conventional one and the introduction of a detailed theoretical study related to the interaction of the JV with the microwave magnetic field lead to new and important results related to properties of high anisotropy superconductors indicating that the EPR spectrometer can be used to investigate properties of high anisotropy superconductors. The failures when using conventional operating method to obtain meaningful results and the method used in the present work to carry out the measurements in a proper manner are presented. Some important results obtained in investigating high anisotropy superconductors by the EPR technique are presented.     

Cup product structure for symplectic K2

For a field F with trivial involution we have the Karoubi L-groups ±1^Ln(F). For 0≤n≤2 these groups are intimately related to subgroups of the classical Witt ring of quadratic forms. -1^L ₂(F) also has a presentation by symbols due to Matsumoto. In terms of this data we make explicit calculations for two cup product maps that appear in the L-theory of fields.     

Simulation of statistical errors in a high-rate fiber-optic communications line

Simple analytical formulas are derived for the approximation of the error probability of data transmission in fiber-optic communications lines. A direct numerical simulation of the propagation of narrow and wide optical pulses is performed. A good agreement of the analytical approximation and the numerical results is demonstrated.     

Rotating class of parametric resonance processes in coupled oscillators

We single out and elucidate basic features of strongly coupled parametric oscillators as opposed by symmetry to the type reducible to uncoupled Mathieu equations. The strongly coupled type is essential to the oscillations and waves in rotating structures and chiral systems. It exhibits only the main parametric resonance, no higher-order ones. As well, the relaxation–fluctuation behavior is unusual, characterized by a negative-energy oscillation mode that is, nonetheless, stable so the Gibbs statistics lose its force. The models presented are exactly solvable.     

Group-renormalization approach in quantum field theory in curved spacetime with torsion

The nature of the interaction of the gauge models SU(N) and O(N) with an external torsion field is studied from the group-renormalization point of view. Consideration of the radiation corrections to the nonminimal interaction gives a possible explanation for the absence of a torsion field in observational data.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 10, pp. 34–38, October, 1990.The authors thank I. L. Buchbinder for discussion of the work.