361 research outputs found

    Anomalous Rabi oscillations in multilevel quantum systems

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    We show that the excitation probability of a state within a manifold of levels undergoes Rabi oscillations with frequency determined by the energy difference between the states and not by the pulse area for sufficiently strong pulses. The observed dynamics can be used as a procedure for robust state preparation as an alternative to adiabatic passage and as a useful spectroscopic method.Comment: 9 pages, 3 figure

    Spectrum for the electric dipole which nonradially falling into a black hole

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    The electromagnetic bremsstrahlung spectrum for the dipole which falling by a spiral orbit into the Schwarzschild black hole was found. The characteristic features in this electromagnetic spectrum can be used for determine of the black hole mass by the new way. This new way (if implemented) provides higher accuracy in determining of the black hole mass. Also these features in the spectrum can be used for determine of the certain characteristics in the black hole magnetosphere or in the accretion disk characteristics around the black hole. It is also shown that the asymptotic behavior of this spectrum (at high frequencies) is practically independent from the impact parameter of the falling dipole.Comment: 15 pages, 3 figures. To appear in IJMPD, 201

    Structural investigation of twinned crystals

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    DEMONSTRATION OF THE EXISTENCE OF THERMAL SURFACE ENERGY AND ITS IMPACTS

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    Using variation principle, we have demonstrated experimentally, for the first time, the existence of the thermal surface energy (TSE), resulting from the oriented motion of charged particles inside a material artefact and the energy of the guided electromagnetic (EM) field, which always accompanies the irregular motion of charged particles. The TSE arises gradually as an evolution process of hysteresis type as a result of interaction of the external EM field, characterized by a mean nonzero value of the Poynting vector, with an ensemble of charged particles of material artefact. It has been demonstrated experimentally that the principle of superposition of the external EM fields is not valid in case of TSE, and an artefact is shown to be in a continuous thermal evolution process, which has no symmetry in space and is irreversible in time, clearly confirming the preceding theoretical results of (Dicke 1954). Such process can be called as thermal synthesis. It is shown that the number of influence parameters, necessary for the description of the thermal evolution process is always huge, thus presenting an experimental confirmation of the fundamental theoretical observation of (Stroud et al. 1972, p.1096). We have shown experimentally for the first time that in a homogeneous material a heat source induces a larger flux of energy in a specified direction, if the energy flux in that direction has been created before by an auxiliary heat source. A deep agreement of our studies with Ancient Indian and Greek Philosophies, as well as with the classical German dialectics is outlined

    EXPERIMENTAL DEMONSTRATION OF THE TIMEIRREVERSIBLE THERMAL EVOLUTION PROCESS AND SOME OF ITS CONSEQUENCES

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    Using a recently developed technique of synchronous differential temperature measurements (Titov & Malinovsky 2005), the existence of the thermal surface energy (TSE) and of thermal hysteresis effect has been demonstrated in metallic gauge blocks (GB). The TSE (described here) is observed if there are inputs of energy and momentum of external electromagnetic (EM) field to material artefact and the heat source is not symmetrically located relative to the artefact surface. The TSE, linearly related to the Poynting vector of the EM field, presents the energy of the oriented motion of the coupled field-particles system inside artifacts. The TSE results in a thermal hysteresis effect, which is irreversible in time and has no symmetry in space. As the principle of superposition is shown not to be valid for EM fields in case of TSE, the hysteresis loop for the continuous sweep in time converts into a spiral, in which the form and the magnitude of the each cycle are slightly different from the ones of the adjacent cycles. In confirmation of the preceding theoretical result (Stroud et al 1972), the number of influence parameters in case of the field-particle system is found to be absolutely enormous, so that the thermal evolution process has, practically, infinite number of the existence and manifestation modes. Our studies present also an experimental confirmation of the basic results of the series of theoretical papers, initiated by R. H. Dicke (1954), in which the interaction of the ensemble of atoms with the electromagnetic field is analyzed

    Urban geochemical changes and pollution with potentially harmful elements in seven Russian cities

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    This paper presents results of an analysis of potentially harmful elements (PHEs, Pb, Zn and Cu) and conservative element (CE, Fe) concentrations in urban surface deposited sediment (USDS). The study was conducted in seven large Russian cities located in different geographic and climatic zones, and in territories with different geology and anthropogenic pressures: Chelyabinsk, Magnitogorsk, Nizhniy Novgorod, Nizhniy Tagil, Rostov-on-Don, Tyumen, and Ufa. The initial geochemical baseline relationships between PHEs and CE concentrations in the USDS were reconstructed for each city applying an approach based on linear weighted fitting of PHE as a function of CE with lower weights assigned to more polluted samples. The reconstructed average initial baseline Pb, Cu, and Zn concentrations varied between 17–52, 25–196, and 91–413 mg kg−1, respectively. Several new criteria for assessing the degree of geochemical transformation and pollution of the urban environment, such as the percentage of polluted samples, average pollutant concentration in polluted samples, and weighting degree index δ, were suggested and compared with common criteria, such as the PHE concentration and the geo-accumulation index. The environmental rank of a city significantly differed depending on whether the criterion for ranking was total PHE pollution or changes in comparison with the initial geochemical baseline. © 2020, The Author(s).Russian Science Foundation, RSF: 18-77-10024The study was supported by Russian Science Foundation (grant No. 18-77-10024)

    Modeling the Young Sun's Solar Wind and its Interaction with Earth's Paleomagnetosphere

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    We present a focused parameter study of solar wind - magnetosphere interaction for the young Sun and Earth,  3.5~3.5 Ga ago, that relies on magnetohydrodynamic (MHD) simulations for both the solar wind and the magnetosphere. By simulating the quiescent young Sun and its wind we are able to propagate the MHD simulations up to Earth's magnetosphere and obtain a physically realistic solar forcing of it. We assess how sensitive the young solar wind is to changes in the coronal base density, sunspot placement and magnetic field strength, dipole magnetic field strength and the Sun's rotation period. From this analysis we obtain a range of plausible solar wind conditions the paleomagnetosphere may have been subject to. Scaling relationships from the literature suggest that a young Sun would have had a mass flux different from the present Sun. We evaluate how the mass flux changes with the aforementioned factors and determine the importance of this and several other key solar and magnetospheric variables with respect to their impact on the paleomagnetosphere. We vary the solar wind speed, density, interplanetary magnetic field strength and orientation as well as Earth's dipole magnetic field strength and tilt in a number of steady-state scenarios that are representative of young Sun-Earth interaction. This study is done as a first step of a more comprehensive effort towards understanding the implications of Sun-Earth interaction for planetary atmospheric evolution.Comment: 16 pages, 7 figure

    Adiabatic population transfer via multiple intermediate states

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    This paper discusses a generalization of stimulated Raman adiabatic passage (STIRAP) in which the single intermediate state is replaced by NN intermediate states. Each of these states is connected to the initial state \state{i} with a coupling proportional to the pump pulse and to the final state \state{f} with a coupling proportional to the Stokes pulse, thus forming a parallel multi-Λ\Lambda system. It is shown that the dark (trapped) state exists only when the ratio between each pump coupling and the respective Stokes coupling is the same for all intermediate states. We derive the conditions for existence of a more general adiabatic-transfer state which includes transient contributions from the intermediate states but still transfers the population from state \state{i} to state \state{f} in the adiabatic limit. We present various numerical examples for success and failure of multi-Λ\Lambda STIRAP which illustrate the analytic predictions. Our results suggest that in the general case of arbitrary couplings, it is most appropriate to tune the pump and Stokes lasers either just below or just above all intermediate states.Comment: 14 pages, two-column revtex style, 10 figure

    Physical Origin of the Boson Peak Deduced from a Two-Order-Parameter Model of Liquid

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    We propose that the boson peak originates from the (quasi-) localized vibrational modes associated with long-lived locally favored structures, which are intrinsic to a liquid state and are randomly distributed in a sea of normal-liquid structures. This tells us that the number density of locally favored structures is an important physical factor determining the intensity of the boson peak. In our two-order-parameter model of the liquid-glass transition, the locally favored structures act as impurities disturbing crystallization and thus lead to vitrification. This naturally explains the dependence of the intensity of the boson peak on temperature, pressure, and fragility, and also the close correlation between the boson peak and the first sharp diffraction peak (or prepeak).Comment: 5 pages, 1 figure, An error in the reference (Ref. 7) was correcte
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