No abstract available

No abstract available

[en] A global treatment is given to the problem proposed by Anderson et al. of finding second order differential equations not admitting pointlike transformations of symmetry but admitting families of local symmetries of non-pointlike character

[en] A generalization of certain results concerning the relation between limit cycles and symmetries of systems of differential equations is given. No restrictions are imposed concerning the linearity of the symmetry vectors (in Rsup(n)) or the canonical nature of the symmetry

[en] Expansion in the density parameter is studied for the energy of the symmetric ground state of a system of N particles. Estimates in the density parameter are obtained for the Feynman diagrams of the perturbation theory in the framework of the saddle point technique in a multidimensional case. The coefficients of the energy expansion in powers of density are expressed in terms of the Faddeev many-particle scattering amplitudes

[en] Lagrangian multipliers in frozen core Dirac-Fock calculations are given in terms of relativistic Slater integrals. The needed coefficients are tabulated. (Auth.)

[en] A problem of charged filament incidence on flat interface of two media with difference values of dielectric permeability epsilon is solved. It is shown, that when the interface is crossed with a source, transition radiation appears. Far from the interface crossing point a field has the form of a spherical wave of the appearing transition radiation. Wave field vectors and superlight source velocity in a wave zone of the source form the angles, satisfying the condition of the Vavilov-Cherenkov radiation. Taking into account, that superlight source velocity can be infinitely high, the Vavilov-Cherenkov radiation is concluded to be present in any medium including vacuum or when epsilon > 1

No abstract available

[en] A quantum method is developed which derives from the theory of rearrangement collisions. The transition probability per unit time between states of two different hamiltonians is determined. The theory is developed for the study of the resonant transition of an electron from an atomic to a metallic state but is easily generalized

[en] The stability properties of a charged-particle-like solution to the equations of motion for the electromagnetic field in a nonlinear gauge are studied. It is first found that the solution is stable for small, time-independent, spherically symmetric perturbations. On examining general, time-dependent, infinitesimal fluctuations, it is found that they are either not allowed or not associated with complex eigenfrequencies, thus implying that the solution is stable. The introduction of a magnetic-dipole moment (spin) is also examined and this can also arise as a solution of the equations of motion if, as expected, it is treated as a first-order quantum effect