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

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

FORMATION OF KEY DEVELOPMENT FACTORS OF TOURIST INFRASTRUCTURE DURING THE PERIOD OF PANDEMIC IN GERMANY

This article allows us to make a conclusion that even in the conditions of pandemic, tourism exists and develops. Internal tourism and international tourism from the nearby European countries prosper In Germany. The pandemic gave an opportunity for realization of innovations in environmental friendliness of tourism, which is quite actual in the 21st century. In addition, technical progress provides an opportunity to see museums, sights of architecture or just walk the streets of foreign cities without leaving home. Tourism is a very flexible sphere of human activity that can adapt to any external terms