Exclusion Statistics in a two-dimensional trapped Bose gas

We briefly explain the notion of exclusion statistics and in particular discuss the concept of an ideal exclusion statistics gas. We then review a recent work where it is demonstrated that a {\em two-dimensional} Bose gas with repulsive delta function interactions obeys ideal exclusion statistics, with a fractional parameter related to the interaction strength.Comment: 10 pages, RevTeX. Proceedings of the Salerno workshop "Theory of Quantum Gases and Quantum Coherence", to appear in a special issue of J.Phys. B, Dec. 200

Nonresonant interaction of ultrashort electromagnetic pulses with multilevel quantum systems

Some features of the excitation of multilevel quantum systems under the action of electromagnetic pulses which are shorter than the inverse frequency of interlevel transitions are considered. It is shown that the interaction is characterized by a specific type of selectivity which is not connected with the resonant absorption of radiation. The simplest three-level model displays the inverse population of upper levels. The effect of an ultrashort laser pulse on a multilevel molecule was regarded as an instant reception of the oscillation velocity by the oscillator and this approach showed an effective excitation and dissociation of the molecule. The estimations testify to the fact that these effects can be observed using modern femtosecond lasers

An embedding potential definition of channel functions

We show that the imaginary part of the embedding potential, a generalised logarithmic derivative, defined over the interface between an electrical lead and some conductor, has orthogonal eigenfunctions which define conduction channels into and out of the lead. In the case of an infinitely extended interface we establish the relationship between these eigenfunctions and the Bloch states evaluated over the interface. Using the new channel functions, a well-known result for the total transmission through the conductor system is simply derived.Comment: 14 pages, 2 figure

Device for Reduction Sparking of Slip Ring of Turbo Generator

Most modern power plants generating electric power equipped with synchronous generators. The correct operation of energy economy depends on reliability of such electrical machines. In this article issue of increasing reliability of turbo generator by increasing reliability of its brush contact unit is considered. Description of brush contact unit and its possible damages is given. Equivalent electrical circuit of contact layer of brush contact unit is performed. The equations are formed and the dynamical simulation model consisting of electric source and two brush contact units is created. With help of this model alternative method of improving parameters of brush contact unit and increasing reliability of turbo generator at once is calculated and shown. The implementation of the proposed method of increasing the turbo generator brush contact units reliability can have different technical performance, but the principle laid down in the method remains the same

Rigorous Analysis of Singularities and Absence of Analytic Continuation at First Order Phase Transition Points in Lattice Spin Models

We report about two new rigorous results on the non-analytic properties of thermodynamic potentials at first order phase transition. The first one is valid for lattice models ($d\geq 2$) with arbitrary finite state space, and finite-range interactions which have two ground states. Under the only assumption that the Peierls Condition is satisfied for the ground states and that the temperature is sufficiently low, we prove that the pressure has no analytic continuation at the first order phase transition point. The second result concerns Ising spins with Kac potentials $J_\gamma(x)=\gamma^d\phi(\gamma x)$, where $0<\gamma<1$ is a small scaling parameter, and $\phi$ a fixed finite range potential. In this framework, we relate the non-analytic behaviour of the pressure at the transition point to the range of interaction, which equals $\gamma^{-1}$. Our analysis exhibits a crossover between the non-analytic behaviour of finite range models ($\gamma>0$) and analyticity in the mean field limit ($\gamma\searrow 0$). In general, the basic mechanism responsible for the appearance of a singularity blocking the analytic continuation is that arbitrarily large droplets of the other phase become stable at the transition point.Comment: 4 pages, 2 figure

Bosonic and fermionic single-particle states in the Haldane approach to statistics for identical particles

We give two formulations of exclusion statistics (ES) using a variable number of bosonic or fermionic single-particle states which depend on the number of particles in the system. Associated bosonic and fermionic ES parameters are introduced and are discussed for FQHE quasiparticles, anyons in the lowest Landau level and for the Calogero-Sutherland model. In the latter case, only one family of solutions is emphasized to be sufficient to recover ES; appropriate families are specified for a number of formulations of the Calogero-Sutherland model. We extend the picture of variable number of single-particle states to generalized ideal gases with statistical interaction between particles of different momenta. Integral equations are derived which determine the momentum distribution for single-particle states and distribution of particles over the single-particle states in the thermal equilibrium.Comment: 6 pages, REVTE

Synthesis, structure and non-linear optical properties of L-argininium perrhenate crystal

A new hybrid organic–inorganic non-linear optical crystalline material, L-argininium perrhenate has been synthesized. The crystal belongs to P212121 space group, has a good optical quality and high transmission in the visible and near infra-red spectral regions. L-argininium perrhenate has high birefringence and is more than four times as efficient as KDP in second harmonic generation, making it a potentially attractive material for non-linear optical applicationsThis work was financially supported by the European Regional Development Fund (ERDF) through Programa Operacional Factores de Competitividade (COMPETE: FCOMP-01-0124-FEDER-014628) and the Portugal Fundacao para a Ciencia e Tecnologia (PTDC/CTM-NAN/114269/2009, PTDC/CTM/105597/2008 and Pest-C/FIS/UI0036/2011)

Youth Organization at an Industrial Enterprise: Educational Problems

Статья посвящена проблемам образования молодежной организации на одном из промышленных предприятий Cвердловской области. Результаты интервью со специалистом по кадрам и анкетирования молодых работников показали наличие проблемы, связанной с отсутствием заинтересованности высшего руководства предприятия в создании молодежной организации и дефицитом молодежных лидеров, способных возглавить работу с молодежью на предприятии.The article is devoted to the problems of formation of a youth organization at one of the industrial enterprises of the Sverdlovsk region. The results of the interview with the HR specialist and the questionnaire survey of young workers showed the presence of a problem related to the lack of interest of the top management of the enterprise in creating a youth organization and the absence of youth leaders to lead the work with youth at the enterprise