543 research outputs found
Radiation Pressure Quantization
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
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
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
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
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
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
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
- …