Nonlinear polaritons in Bose-Einstein condensates in optical lattices

We study the interaction of a Bose-Einstein condensate in an optical lattice with additional electromagnetic fields under Raman resonance condition. System of evolution equations describing ultra-short optical pulse propagation and photo-induced transport of cold atoms in optical lattice is derived. The steady state solution of these equations was found. There are new kinds of polaritonic solitary waves propagating.Comment: pdf-file, Reported on "IX International Readings on Quantum Optics", 12-17 October, St-Peterburg, Russi

Main factors affecting the structure and properties of titanium and cobalt alloys manufactured by the 3D printing

This paper is short review the main factors affecting the structure and properties of the metals manufactured by additive technology (selective laser melting). A comparative analysis of the structure and properties of Ti6Al4V or CoCrMo alloys obtained by selective laser melting is presented. We describe the capabilities of laser melting method for producing materials with high density and high mechanical properties. The optimized process parameters for 3D printed medicine materials Ti6Al4V and CoCrMo with high density of are discussed. © Published under licence by IOP Publishing Ltd.This work was supported by Russian Found of Basic Research N “Diagnostics” AAAA-A18-118020690196-3

Polariton Propagation in Imperfect Resonantly Absorbing Bragg grating

The nonlinear polariton transmission through resonantly absorbing Bragg grating (RABG) with randomly varying lattice spacing is studied. In this work are presented the results of numerical simulation of propagation stability of polaritonic solitary wave consisting of matter wave coupled with counter propagating light waves which propagate through dielectric medium, containing periodically placed in the dielectric waveguide thin dielectric films with metallic nanoparticles (or quantum dots, nanoagregates with nonlinear dielectric properties). The influence of lattice spacing deviations from mean value (average) of the lattice spacing is described in the model equations by random multiplicative noise set in the phases of forward and backward electric components of electromagnetic wave. As the initial condition it was used the solitary wave solution of the model describing nonlinear wave propagation in perfect nonlinear RABG. The results of numerical simulations show that phase fluctuations lead to periodic oscillations (with the period

Expresión constitucional y legal del principio de diversidad ideológica en la legislación relacionada con asociaciones públicas y partidos políticos

The aim of this study is to carry out a comprehensive study of theoretical research and the practice of implementing the constitutional and legal principle of ideological diversity in the activities of public associations and political parties, and to develop recommendations and proposals for improving legal regulation in this area. According to the results of the research, the conclusions were made that the implementation of the constitutional principle of ideological diversity is one of the conditions for the development of any democratic state based on the rule of law. In the Russian Federation, conditions have been created at the legislative level for the development of the constitutional principle of ideological diversity. The legislation related to the public associations and political parties plays an important role in the implementation of this constitutional principle, but the mechanisms for its implementation still need to be improved.El objetivo de este estudio es llevar a cabo un estudio exhaustivo de la investigación teórica y la práctica de implementar el principio constitucional y legal de la diversidad ideológica en las actividades de asociaciones públicas y partidos políticos, y desarrollar recomendaciones y propuestas para mejorar la regulación legal en esta zona. Según los resultados de la investigación, se llegó a la conclusión de que la implementación del principio constitucional de la diversidad ideológica es una de las condiciones para el desarrollo de cualquier estado democrático basado en el estado de derecho. En la Federación de Rusia, se han creado condiciones a nivel legislativo para el desarrollo del principio constitucional de la diversidad ideológica. La legislación relacionada con las asociaciones públicas y los partidos políticos juega un papel importante en la implementación de este principio constitucional, pero los mecanismos para su implementación aún deben mejorarse

Propagation and interaction of ultrashort electromagnetic pulses in nonlinear media with a quadratic-cubic nonlinearity

Propagation of extremely short unipolar pulses of electromagnetic field ("videopulses") is considered in the framework of a model in which the material medium is represented by anharmonic oscillators (approximating bound electrons) with quadratic and cubic nonlinearities. Two families of exact analytical solutions (with positive or negative polarity) are found for the moving solitary pulses. Direct simulations demonstrate that the pulses are very robust against perturbations. Two unipolar pulses collide nearly elastically, while collisions between pulses with opposite polarities and a small relative velocity are inelastic, leading to emission of radiation and generation of a small-amplitude additional pulse.Comment: 12 pages, 10 figure