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

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

Solitary electromagnetic waves propagation in the asymmetric oppositely-directed coupler

We consider the electromagnetic waves propagating in the system of coupled waveguides. One of the system components is a standard waveguide fabricated from nonlinear medium having positive refraction and another component is a waveguide produced from an artificial material having negative refraction. The metamaterial constituting the second waveguide has linear characteristics and a wave propagating in the waveguide of this type propagates in the direction opposite to direction of energy flux. It is found that the coupled nonlinear solitary waves propagating both in the same direction are exist in this oppositely-directed coupler due to linear coupling between nonlinear positive refractive waveguide and linear negative refractive waveguide. The corresponding analytical solution is found and it is used for numerical simulation to illustrate that the results of the solitary wave collisions are sensible to the relative velocity of the colliding solitary waves.Comment: 9 pages,5 figure

Chemistry for engineering education

We will look at the practical implementation of the disciplines of chemistry intechnological orientation programs. It is shown that with the uniformrequirements of the GEF to the quality of training, volumes for disciplines ofchemistry differ significantly. These shortcomings inherent in the existingteaching methods and ways to improve the learning process are discussed. Notedthat the promising direction of the basic educational program is to build themin a modular fashion.Рассмотрена практика реализации дисциплин химии в программах технологической направленности. Показано, что при единых требованиях ФГОС к качеству подготовки специалистов объемы дисциплин химии существенно различаются. Указаны недостатки, присущие существующей методике обучения, и рассмотрены пути повышения эффективности учебного процесса. Отмечено, что перспективным направлением реализации ООП является построение их по модульному принципу

Non-linear determined methodology of professional-pedagogic education

The article describes the approach to professional-pedagogic education’s designing on the base of non-linear determined methodologyВ статье рассматривается подход к проектированию профессионально-педагогического образования на основе нелинейно-детерминированной методологи

Response evolution of a tetrachiral metamaterial unit cell under architectural transformations

This paper studies a mechanical metamaterial with tetrachiral topology by mathematical modeling. Chirality is the property of an object that makes the object distinguishable from its mirror image; chirality can be left‐ or right‐handed. The mechanical response of two metamaterial unit cells with different configurations (patterns A and B) is investigated. It is found that the cubic cell with a regular pattern A exhibits orthotropic mechanical behavior under loading along three coordinate axes. An irregular pattern B differs from pattern A in that the upper face of the unit cell has an opposite chirality. This architectural transformation is considered as a topological defect, which enhances the twisting effect in the loaded metamaterial. Analysis of displacements and stresses shows that the mechanical behavior of the pattern B cell is described by the model of a transversely isotropic material. The orthotropic and transversely isotropic behavior of the cells of given configurations is also confirmed by the values of the effective elastic constants. Microstructural geometry and mechanical deformation of metamaterials are shown to be closely related. It is shown that a topological defect in a unit cell of a tetrachiral metamaterial strongly determines its twisting behavior