543 research outputs found

    Radiation Pressure Quantization

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    Kepler's observation of comets tails initiated the research on the radiation pressure of celestial objects and 250 years later they found new incarnation after the Maxwell's equations were formulated to describe a plethora of light-matter coupling phenomena. Further, quantum mechanics gave birth to the photon drag effect. Here, we predict a novel universal phenomenon which can be referred to as quantization of the radiation pressure. We develop a microscopic theory of this effect which can be applied to a general system containing Bose-Einstein-condensed particles, which possess an internal structure of quantum states. By analyzing the response of the system to an external electromagnetic field we find that such drag results in a flux of particles constituting both the condensate and the excited states. We show that in the presence of the condensed phase, the response of the system becomes quantized which manifests itself in a step-like behavior of the particle flux as a function of electromagnetic field frequency with the elementary quantum determined by the internal energy structure of the particles.Comment: Manuscript: 4 pages, 3 figure

    Wave scattering by discrete breathers

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    We present a theoretical study of linear wave scattering in one-dimensional nonlinear lattices by intrinsic spatially localized dynamic excitations or discrete breathers. These states appear in various nonlinear systems and present a time-periodic localized scattering potential for plane waves. We consider the case of elastic one-channel scattering, when the frequencies of incoming and transmitted waves coincide, but the breather provides with additional spatially localized ac channels whose presence may lead to various interference patterns. The dependence of the transmission coefficient on the wave number q and the breather frequency Omega_b is studied for different types of breathers: acoustic and optical breathers, and rotobreathers. We identify several typical scattering setups where the internal time dependence of the breather is of crucial importance for the observed transmission properties.Comment: 17 pages, 19 figures, submitted to CHAOS (Focus Issue

    Radiation Pressure Quantization

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    Kepler's observation of comets tails initiated the research on the radiation pressure of celestial objects and 250 years later they found new incarnation after the Maxwell's equations were formulated to describe a plethora of light-matter coupling phenomena. Further, quantum mechanics gave birth to the photon drag effect. Here, we predict a novel universal phenomenon which can be referred to as quantization of the radiation pressure. We develop a microscopic theory of this effect which can be applied to a general system containing Bose-Einstein-condensed particles, which possess an internal structure of quantum states. By analyzing the response of the system to an external electromagnetic field we find that such drag results in a flux of particles constituting both the condensate and the excited states. We show that in the presence of the condensed phase, the response of the system becomes quantized which manifests itself in a step-like behavior of the particle flux as a function of electromagnetic field frequency with the elementary quantum determined by the internal energy structure of the particles.Comment: Manuscript: 4 pages, 3 figure

    Applied bachelor degree programme as the direction of mobile social teachers training in the conditions of professional and mobile practice

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    The relevance is caused by the need to train mobile social teachers with a high level of adaptation to the changing working conditions and capable timely, reasonably, optimally and quickly to solve social and pedagogical problems of people of different age and social categories. The purpose of the article is in defining the role of applied bachelor degree in training of mobile social teachers in the conditions of professional - mobile practice. The leading method is comparative analysis of social teachers training in the conditions of state educational standard of 2005 and new generation standard FGOS-2010. The article presents the method of projects as the leading kind of activity of practice-oriented training in the direction of applied bachelor degree of future social teachers in the conditions of practice. The method of project activity can be realized in training of specialists in different direction of training and profile. © 2019 by the authors

    Light scattering by a finite obstacle and Fano resonances

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    The conditions for observing Fano resonances at elastic light scattering by a single finite-size obstacle are discussed. General arguments are illustrated by consideration of the scattering by a small (relative to the incident light wavelength) spherical obstacle based upon the exact Mie solution of the diffraction problem. The most attention is paid to recently discovered anomalous scattering. An exactly solvable one-dimentional discrete model with nonlocal coupling for simulating diffraction in wave scattering in systems with reduced spatial dimensionality is also introduced and analyzed. Deep connections between the resonances in the continuous and discrete systems are revealed

    INTELLIGENT SYSTEM OF TRAFFIC LIGHT CONTROL WITH DYNAMIC CHANGE PHASES OF TRAFFIC FLOWS ON CONTROLLED INTERSECTIONS

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    There was method of making an effective system of traffic-light control of the traffic through the intersections in one direction according to which the phase coefficients for each cycle of traffic-light control are computed in real- time using the data of traffic intensity detected by transport detectors. Thus, the built-in traffic control system will be dynamically adapted to the change in the intensity of traffic flows, and the structure of the cycle and its duration will be changed taking into account the parameters of the traffic flow at the intersection. Accordingly, the traffic light cycle, where each cycle has the minimum required duration, will be most effective and will ensure uninterrupted traffic, the lack of traffic jams and the convenience for the pedestrian crossings.There was method of making an effective system of traffic-light control of the traffic through the intersections in one direction according to which the phase coefficients for each cycle of traffic-light control are computed in real- time using the data of traffic intensity detected by transport detectors. Thus, the built-in traffic control system will be dynamically adapted to the change in the intensity of traffic flows, and the structure of the cycle and its duration will be changed taking into account the parameters of the traffic flow at the intersection. Accordingly, the traffic light cycle, where each cycle has the minimum required duration, will be most effective and will ensure uninterrupted traffic, the lack of traffic jams and the convenience for the pedestrian crossings

    Dust Emission from Herbig Ae/Be stars - Evidence for Disks and Envelopes

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    IR and mm-wave emission from Herbig Ae/Be stars has produced conflicting conclusions regarding the dust geometry in these objects. We show that the compact dimensions of the mm-wave emitting regions are a decisive indication for disks. But a disk cannot explain the spectral energy distribution (SED) unless it is embedded in an extended envelope that (1) dominates the IR emission and (2) provides additional disk heating on top of the direct stellar radiation. Detailed radiative transfer calculations based on the simplest model for envelope-embedded disks successfully fit the data from UV to mm wavelengths and show that the disks have central holes. This model also resolves naturally some puzzling results of IR imaging.Comment: 9 pages, 2 figures. accepted to ApJ
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