We observe and analyze strongly nonlinear photoluminescence kinetics of indirect excitons in GaAs/AlGaAs coupled quantum wells at low bath temperatures, > or = 50 mK. The long recombination lifetime promotes accumulation these Bose particles the lowest energy states allows photoexcited to cool down temperatures where dilute 2D gas becomes statistically degenerate. Our main result--a strong enhancement exciton scattering rate low-energy with increasing concentration excitons--reveals bosonic...

Quasi-equilibrium relaxational thermodynamics is developed to understand LA-phonon-assisted thermalization of Bose-Einstein distributed excitons in quantum wells. We study the quantum-statistical effects dynamics effective temperature $T = T(t)$. When $T$ less than degeneracy $T_0$, well-developed statistics well leads nonexponential and density-dependent thermalization. At low bath temperatures $T_b \to 0$ quantum-statistically degenerate effectively slows down $T(t) \propto 1 / \ln t$....

Optical trapping and manipulation of neutral particles has led to a variety experiments from stretching DNA-molecules cooling atoms. An exciting recent outgrowth the technique is an experimental implementation atom Bose-Einstein condensation. In this paper, we propose demonstrate laser induced for new system--a gas excitons in quantum well structures. We report on highly degenerate Bose traps.

We report on the study of indirect excitons in moving lattices - conveyers created by a set AC voltages applied to electrodes sample surface. The wavelength this lattice is electrode periodicity, amplitude controlled voltage, and velocity frequency. observed dynamical localization-delocalization transition for measured its dependence exciton density conveyer velocity. considered model transport via conveyers. theoretical simulations are agreement with experimental data.

This paper presents the process of automated designing and parametric modeling excavator buckets using CAD system. A methodology has been developed that covers all stages design, from creation 3D models parts, sub-assemblies, assemblies to generation design documentation, template files. The presented approach allows with multiple configurations, which cover different variants products according their technical characteristics purpose. describes in detail technological process, including...

For the low-excitation regime a self-consistent set of equations for excitons (x), exciton molecules (m), and photons (\ensuremath{\gamma}) is derived from electron-hole-photon Hamiltonian, taking spin explicitly into account. In this approach creation m occurs via Coulombic scattering two x's opposite internal structure. This process resonant due to polariton effect. Thus, matrix element x+x\ensuremath{\rightarrow}m governs formation, rather than optical...

In order to explain and model the inner ring in photoluminescence (PL) patterns of indirect excitons GaAs/AlGaAs quantum wells (QWs), we develop a microscopic approach formulated terms coupled nonlinear equations for diffusion, thermalization optical decay particles. The origin is unambiguously identified: it due cooling their propagation from excitation spot. We infer that our high-quality structures in-plane diffusion coefficient about 10-30cm^2/s amplitude disorder potential 0.45meV.

Social media informs the public about most important events and conveys information.Before, during, after disasters, social are used to disseminate information disasters collect data relevant implementation of preparedness, response, recovery activities measures.Social networks effective in disseminating warnings, as well educating public.The subject research is examining influence demographic factors on effectiveness informing risks disasters.Using an online survey questionnaire according...

We introduced an elevated trap technique and exploited it for lowering the effective temperature of indirect excitons. observed narrow photoluminescence lines which correspond to emission individual states excitons in a disorder potential. studied effect exciton-exciton interaction on localized delocalized exciton found that homogeneous line broadening increases with density dominates linewidth at high densities.

A model for diffusion of statistically degenerate excitons in (coupled) quantum wells is proposed and analysed. Within a microscopic approach, we derive equation, calculate estimate the self-diffusion coefficient modified Einstein relation adapted to degenerated quasi–two-dimensional bosons. It also shown that dipole-dipole interaction indirect effectively screens long-range–correlated disorder wells. Numerical calculations are given GaAs/AlGaAs coupled

Whispering gallery modes (WGMs) in dielectric microcylinders are investigated numerically as sensitive probes of the surrounding medium, for applications chemical sensing and biosensing. We consider a geometry where WGMs exited via frustrated total internal reflection from planar substrate, reported recent experiments. The optical coupling between substrate cylinder yields WGM broadening exponentially decreasing with increasing distance substrate. also separation layer that results shift...

We report on the kinetics of inner ring in exciton emission pattern. The formation time following onset laser excitation is found to be about 30 ns. also disappear within 4 ns after termination. latter process accompanied by a jump photoluminescence (PL) intensity. spatial dependence PL indicates that excitons outside region excitation, including region, are efficiently cooled lattice temperature even during excitation. and disappearance explained terms transport cooling.

An exciton crystal (EC) is predicted in a quasi-one-dimensional (1D) semiconductor quantum wire for the densities (1${\mathit{r}}_{\mathit{s}}$\ensuremath{\le}5.5) due to repulsive interaction between singlet excitons (x's). Low-lying excitations, stability, and melting of EC are determined within Heitler-London approximation. The expected short condensation times (ps) will allow an formation in, e.g., GaAs quantum-well wires with relative x lifetimes. For T\ensuremath{\le}10 K pure which...

The optical properties of excitonic molecules (XXs) in GaAs-based quantum well microcavities (MCs) are studied, both theoretically and experimentally. We show that the radiative corrections to XX state, Lamb shift $\Delta^{\rm MC}_{\rm XX}$ width $\Gamma^{\rm XX}$, large, about $10-30 %$ molecule binding energy $\epsilon_{\rm definitely cannot be neglected. optics is dominated by in-plane resonant dissociation into outgoing 1$\lambda$-mode 0$\lambda$-mode cavity polaritons. later decay...

A literature review has been conducted, helping outline some of the main peculiarities that exists within 3D object file format domain. The difficulties are present when working with different formats in various fields have noted – incompatibility issues, data loss, conversion difficulties, software wrappers, manufacturing industry standards and more. problem comparison defined workflows bogged down by output tools use, expertise is a requirement, conversion, complexity themselves...

The influence of the polariton effects on internal structure an excitonic molecule ($\mathrm{xx}$) is examined by solution new $\mathrm{xx}$ Schr\"odinger equation which includes self-consistently. In 3D (CuCl) radiative renormalizations yield a nonparabolic dispersion with infinite effective mass at zero momentum; in quasi-2D (GaAs) they give rise to "Mexican hat" small momenta together considerable increase both binding energy ${\ensuremath{\epsilon}}^{\mathrm{xx}}$ and inverse lifetime...

We report on the two-beam study of indirect excitons in inner ring exciton emission pattern. One laser beam generates and a second weaker is positioned ring. The found to locally suppress intensity. also fragmentation formation multiple rings region. These features are originate from weak spatial modulation excitation intensity anticorrelates with three phenomena---inner fragmentation, region, suppression by ring---have common feature: reduction region enhanced excitation. This effect...

The report contains a description of augmented reality technology application in the education and training mechanical engineers. Software for marker tracking engineering is created described. An approach design textbook with 3D models cutting tools, measuring tools special equipment, visualised using presented.

Nowadays innovative technologies are entering the educational process with aim of learners easily understanding and learning material provided. The used and/or based on virtual augmented reality in affects today's digital generation motivation learners, giving them opportunity to use their smartphones process. paper is show main positive aspects 3D Virtual Reality environments Augmented Learning mechanical engineering education. An interactive Mobile Apps for environment setting up operating...

The thermalization of a low-density gas excitons in ${\mathrm{Cu}}_{2}\mathrm{O}$ is analyzed within the phonon-assisted Boltzmann kinetics presence weak interaction with light field. For optically quadrupole-allowed orthoexcitons, formulated terms polariton picture. A ``bottleneck'' relaxation along lower branch strongly dominates over accumulation orthoexcitons energy minimum upper dispersion branch. paraexcitons, which are strictly forbidden resonant optical transitions, rather slow...

The thermalization and photoluminescence (PL) dynamics of indirect excitons in GaAs/AlGaAs coupled quantum wells (QWs) at very low bath temperature, Tb<1 K, are analysed theoretically modelled numerically order to clarify the origin recently observed sharp increase PL signal (PL-jump) right after a high-intensity excitation pulse. We conclude that PL-jump effect is mainly due classical cooling pump pulse, which heats exciton system. Thus cannot unambiguously be attributed bosonic stimulation...