3,758 research outputs found

    Projector operators for the no-core shell model

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    Projection operators for the use within ab initio no-core shell model, are suggested.Comment: 3 page

    Interaction of Radiation and a Relativistic Electron in Motion in a Constant Magnetic Field

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    The work examines the effect of multiple photon emission on the quantum mechanical state of an electron emitting synchrotron radiation and on the intensity of that radiation. Calculations are done with the variant of perturbation theory based on the use of extended coherent states. A general formula is derived for the number of emitted photons, which allows for taking into account their mutual interaction. A model problem is used to demonstrate the absence of the infrared catastrophe in the modified perturbation theory. Finally, the electron density matrix is calculated, and the analysis of this matrix makes it possible to conclude that the degree of the elecron's spatial localization increases with the passage of time if the electron is being accelerated.Comment: 29 pages, no figure

    Algebraic Model for scattering in three-s-cluster systems. I. Theoretical Background

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    A framework to calculate two-particle matrix elements for fully antisymmetrized three-cluster configurations is presented. The theory is developed for a scattering situation described in terms of the Algebraic Model. This means that the nuclear many-particle state and its asymptotic behaviour are expanded in terms of oscillator states of the intra-cluster coordinates. The Generating Function technique is used to optimize the calculation of matrix elements. In order to derive the dynamical equations, a multichannel version of the Algebraic Model is presented.Comment: 20 pages, 1 postscript figure, submitted to Phys. Rev.

    Age features of O2 mass transfer regimes in adolescents’ body at rest

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    The results of complex studies of the quantitative relationship between the stage-by-stage mass transfer of O2 and the efficiency of cardiorespiratory system functioning in relation to its consumption in adolescents’ body under conditions of relative rest are presented. The results obtained show that in adolescents, the modes of mass transfer of O2 in the body and the nature of the respiratory and circulatory systems functioning in relation to its consumption have a number of age-related differences compared with adult men. So, in adolescents, the external respiration system at rest functions less economically than in adults. Each liter of O2 consumed by adolescents is extracted from almost 3 liters more than in adults the amount of air ventilated per minute through the lungs. The volumetric indicators of blood circulation are also higher in adolescents, which may indicate the influence of neuro-humoral rearrangements in the body during the pubertal period. The coefficient of oxygen utilization by tissues from arterial blood in adolescents turned out to be significantly higher, which may characterize a higher tension of tissue metabolic processes

    Nucleon-nucleon interaction in the JJ-matrix inverse scattering approach and few-nucleon systems

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    The nucleon-nucleon interaction is constructed by means of the JJ-matrix version of inverse scattering theory. Ambiguities of the interaction are eliminated by postulating tridiagonal and quasi-tridiagonal forms of the potential matrix in the oscillator basis in uncoupled and coupled waves, respectively. The obtained interaction is very accurate in reproducing the NNNN scattering data and deuteron properties. The interaction is used in the no-core shell model calculations of 3^3H and 4^4He nuclei. The resulting binding energies of 3^3H and 4^4He are very close to experimental values.Comment: Text is revised, new figures and references adde

    Convex ordering and quantification of quantumness

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    The characterization of physical systems requires a comprehensive understanding of quantum effects. One aspect is a proper quantification of the strength of such quantum phenomena. Here, a general convex ordering of quantum states will be introduced which is based on the algebraic definition of classical states. This definition resolves the ambiguity of the quantumness quantification using topological distance measures. Classical operations on quantum states will be considered to further generalize the ordering prescription. Our technique can be used for a natural and unambiguous quantification of general quantum properties whose classical reference has a convex structure. We apply this method to typical scenarios in quantum optics and quantum information theory to study measures which are based on the fundamental quantum superposition principle.Comment: 9 pages, 2 figures, revised version; published in special issue "150 years of Margarita and Vladimir Man'ko

    Fractal-like aggregates: Relation between morphology and physical properties

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    A number of modern technological applications require a detailed calculation of the physical properties of aggregated aerosol particles. For example, in probing soot aerosols by the method called laser-induced incandescence (LII), the soot clusters are suddenly heated by a short, powerful laser pulse and then cool down to the temperature of the carrier gas. LII sizing is based on rigorous calculation of the soot aggregate heat-up and cooling and involves prediction of laser light absorption and energy and mass transfer between aggregated particles and the ambient gas. This paper describes results of numerical simulations of the mass or energy transfer between the gas and fractal-like aggregates of N spherical particles in either the free-molecular or continuum regime, as well as the light scattering properties of random fractal-like aggregates, based on Rayleigh–Debye–Gans (RDG) theory. The aggregate geometries are generated numerically using specially developed algorithms allowing “tuning” of the fractal dimension and prefactor values. Our results are presented in the form of easily applicable scaling laws, with special attention paid to relations between the aggregate gyration radius and the effective radius describing various transport processes between the aggregates and the carrier gas

    Supersymmetric reduced models with a symmetry based on Filippov algebra

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    Generalizations of the reduced model of super Yang-Mills theory obtained by replacing the Lie algebra structure to Filippov nn-algebra structures are studied. Conditions for the reduced model actions to be supersymmetric are examined. These models are related with what we call \{cal N}_{min}=2 super pp-brane actions.Comment: v3: In the previous versions we overlooked that Eq.(3.9) holds more generally, and missed some supersymmetric actions. Those are now included and modifications including a slight change in the title were made accordingly. 1+18 page
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