7,254 research outputs found
Mega-clusters as a tool of interregional cooperation in tourists field
In order to diversify the Russian economy, it is necessary to pay great attention to the emerging sectors of the economy; with a systemic approach they are able to reveal their accumulated potential. Authors consider one of such industries to be the sphere of tourism. Russia has its own unique natural-recreational and cultural-historical potential, which is not fully utilized, and it is confirmed with the relevant statistics. The authors propose to accelerate the development of tourism by raising the level of interregional cooperation from the position of using coexisting competition and competitive coexistence in tourist mega-clusters. Due to the lack of financial resources for separate regions for the tourism development, the implementation of this approach is effective, as it allows achieving savings of money due to economies of scale. The phenomena of coexisting competition and competitive coexistence in the tourism sphere presuppose the unification of the different regions authorities’ efforts for the joint implementation of projects. Regions joining forces on the basis of coexisting competition and competitive coexistence within the mega-clusters will allow each administrative-territorial unit to develop and improve its competitive advantage by asking a stimulus to the development of the other participants. This approach makes it possible to obtain other positive effects noted in the study. Thus, findings broaden the knowledge about the phenomena of coexisting competition and competitive coexistence in the regional economy, about mega-clusters as tools for interregional interactions in the tourism sphere
Long-distance entanglement and quantum teleportation in XX spin chains
Isotropic XX models of one-dimensional spin-1/2 chains are investigated with
the aim to elucidate the formal structure and the physical properties that
allow these systems to act as channels for long-distance, high-fidelity quantum
teleportation. We introduce two types of models: I) open, dimerized XX chains,
and II) open XX chains with small end bonds. For both models we obtain the
exact expressions for the end-to-end correlations and the scaling of the energy
gap with the length of the chain. We determine the end-to-end concurrence and
show that model I) supports true long-distance entanglement at zero
temperature, while model II) supports {\it ``quasi long-distance''}
entanglement that slowly falls off with the size of the chain. Due to the
different scalings of the gaps, respectively exponential for model I) and
algebraic in model II), we demonstrate that the latter allows for efficient
qubit teleportation with high fidelity in sufficiently long chains even at
moderately low temperatures.Comment: 9 pages, 6 figure
Magneto-optical Feshbach resonance: Controlling cold collision with quantum interference
We propose a method of controlling two-atom interaction using both magnetic
and laser fields. We analyse the role of quantum interference between magnetic
and optical Feshbach resonances in controlling cold collision. In particular,
we demonstrate that this method allows us to suppress inelastic and enhance
elastic scattering cross sections. Quantum interference is shown to modify
significantly the threshold behaviour and resonant interaction of ultracold
atoms. Furthermore, we show that it is possible to manipulate not only the
spherically symmetric s-wave interaction but also the anisotropic higher
partial-wave interactions which are particularly important for high temperature
superfluid or superconducting phases of matter.Comment: 7 pages 3 figures, some minor errors are corrected, Accepted in J.
Phys.
Unstable Hadrons in Hot Hadron Gas in Laboratory and in the Early Universe
We study kinetic master equations for chemical reactions involving the
formation and the natural decay of unstable particles in a thermal bath. We
consider the decay channel of one into two particles, and the inverse process,
fusion of two thermal particles into one. We present the master equations the
evolution of the density of the unstable particles in the early Universe. We
obtain the thermal invariant reaction rate using as an input the free space
(vacuum) decay time and show the medium quantum effects on reaction relaxation time. As another laboratory example
we describe the process in thermal hadronic gas in
heavy-ion collisions. A particularly interesting application of our formalism
is the process in the early Universe.
We also explore the physics of and freeze-out in the
Universe.Comment: 13 pages, 9 figures, published in Physical Review
Optical studies of the X-ray transient XTE J2123-058 -I. Photometry
We present optical photometry of the X-ray transient XTE J2123-058, obtained
in July-October 1998. The light curves are strongly modulated on the 5.95hrs
orbital period, and exhibit dramatic changes in amplitude and form during the
decline. We used synthetic models which include the effect of partial eclipses
and X-ray heating effects, to estimate the system parameters, and we constrain
the binary inclination to be i=73+-4 degrees. The model is successful in
reproducing the light curves at different stages of the decay by requiring the
accretion disc to become smaller and thinner by 30% as the system fades by 1.7
mags in the optical. From Aug 26 the system reaches quiescence with a mean
magnitude of R=21.7+-0.1 and our data are consistent with the optical
variability being dominated by the companion's ellipsoidal modulation.Comment: 6 pages, 6 figure
Suppression of power-broadening in strong-coupling photoassociation in the presence of a Feshbach resonance
Photoassociation (PA) spectrum in the presence of a magnetic Feshbach
resonance is analyzed. Nonperturbative solution of the problem yields
analytical expressions for PA linewidth and shift which are applicable for
arbitrary PA laser intensity and magnetic field tuning of Feshbach Resonance.
We show that by tuning magnetic field close to Fano minimum, it is possible to
suppress power broadening at increased laser intensities. This occurs due to
quantum interference of PA transitions from unperturbed and perturbed
continuum. Line narrowing at high laser intensities is accompanied by large
spectral shifts. We briefly discuss important consequences of line narrowing in
cold collisions.Comment: 12 pages, 5 figure
Popularization of scientific knowledge among school children is a priority of the educational policy of the Omsk State Technical University
В статье представлен опыт Омского государственного технического университета по популяризации научных знаний среди детей, выявлении талантливой молодежи в рамках поддержки инновационного развития экономики России и ее регионов.The article presents the experience of the Omsk State Technical University in popularizing scientific knowledge among children and in detecting talented youth under the terms of support of innovative development of the economy of Russia and its regions
DEVELOPMENT OF A MODEL FOR THE PRODUCTION OF METAL-POWDER COMPOSITIONS BASED ON CO-CR ALLOYS BY ELECTROEROSIVE DISPERSION
Abstract. The main requirement for powders for additive 3d technologies is the spherical shape of theparticles. Such particles are most compactly packed into a certain volume and ensure the "fluidity" of the powder composition in the supply systems of the material with minimal resistance. The wide use of the EED method for processing metal waste into powders for the purpose of their reuse and application in additive technologies is hampered by the lack in the scientific and technical literature of full-fledged information on the effect of the initial composition, regimes and media on the properties of powders and technologies of practical application. Therefore, in order to develop technologies for the reuse of electroerosive powders and to evaluate the effectiveness of their use, complex theoretical and experimental studies are required. The aim of the work was to develop a model for the production of metal powder compositions on the basis of Co-Cr alloys by electroerosive dispersion. Based on the results of the conducted studies, it has been established that the optimum parameters for the process of obtaining powder materials by the method of electroerosive dispersion of butyl alcohol are: capacitance of discharge capacitors 48 μF, voltage on electrodes 100 V, repetition rate of pulses 120 Hz
Optically Controlled Excitonic Transistor
Optical control of exciton fluxes is realized for indirect excitons in a
crossed-ramp excitonic device. The device demonstrates experimental proof of
principle for all-optical excitonic transistors with a high ratio between the
excitonic signal at the optical drain and the excitonic signal due to the
optical gate. The device also demonstrates experimental proof of principle for
all-optical excitonic routers
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