Optical vortices and the flow of their angular momentum in a multimode fiber

The problem of propagation of optical vortices in multimode fibers is considered. The structural changes experienced by the wave and ray surfaces in their transformation from the free space to a fiber medium are determined. The continuity equation is obtained for the flow of the vortex angular momentum in an unhomogeneous medium.Розглядається проблема розповсюдження оптичних вихорів в багатомодових волокнах. Показано які структирнихзмін дізнають хвильова і променева поверхні при переході із вільного простору в середовище волокна. Записане рівняння неперервності для потоку кутового момента вихоря в неоднорідному середовищі.Рассматривается проблема распространения оптических вихрей в многомодовых волокнах. Показано какие структурные изменения испытывают волновая и лучевая поверхности при переходе из свободного пространства в среду волокна. Записано уравнение непрерывности для потока углового момента вихря в неоднородной среде

Certain aspects of regularity in scalar field cosmological dynamics

We consider dynamics of the FRW Universe with a scalar field. Using Maupertuis principle we find a curvature of geodesics flow and show that zones of positive curvature exist for all considered types of scalar field potential. Usually, phase space of systems with the positive curvature contains islands of regular motion. We find these islands numerically for shallow scalar field potentials. It is shown also that beyond the physical domain the islands of regularity exist for quadratic potentials as well.Comment: 15 pages with 4 figures; typos corrected, final version to appear in Regular and Chaotic Dynamic

Spin-orbit interaction in a generic vortex field transmitted through an elliptic fiber

Any small external perturbation on an ideal round optical fiber induces cross - section deformation and transforms eigen guided vortices into generic vortex fields, which can change their structure and angular momentum. It is the properties of these vortical fields in an elliptic weakly guiding optical fiber that we consider in this paper. The eigenfunctions and the spectrum of polarization corrections to the scalar propagation constant in the case of relatively large and small values of a fiber ellipticity are obtained by means of the spin-orbit interaction operator method. Discussed is the conversion process of a spin and orbit angular momenta on a vortex propagation along a deformed fiber

Principles of equitable reparation in the case of compulsory alienation of immovable property

The relevance of the problems investigated in the article is due to the fact that the questions about what “equitable reparation” means and how the value of compulsory alienated property should be calculated are of a fundamental nature. The purpose of the article was to establish the principles of equitable reparation in the case of compulsory alienation of immovable property in the Russian Federation. The leading research method for this problem is the analysis method, which allowed studying the legislation of the Russian Federation on this issue and highlighting the principles of equitable reparation in the case of forced transfer of immovable property on the basis of judicial practice. The article identified four principles of equitable reparation in Russian law; it was established that the legislation and judicial practice in determining reparation in the event of compulsory alienation of immovable property in the Russian Federation are imperfect, which leads to numerous litigation in the event of disagreement about the valuation of property; the necessity of defining the concept of “equitable reparation” in regulatory legal acts was explained. © Rushing Water Publishers Ltd. 2019

Combined operative interventions in patients with diseases of the blood

[No abstract available

Combined operative interventions in patients with diseases of the blood

[No abstract available