1,396 research outputs found

    Fibre bundle formulation of nonrelativistic quantum mechanics. III. Pictures and integrals of motion

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    We propose a new systematic fibre bundle formulation of nonrelativistic quantum mechanics. The new form of the theory is equivalent to the usual one but it is in harmony with the modern trends in theoretical physics and potentially admits new generalizations in different directions. In it a pure state of some quantum system is described by a state section (along paths) of a (Hilbert) fibre bundle. It's evolution is determined through the bundle (analogue of the) Schr\"odinger equation. Now the dynamical variables and the density operator are described via bundle morphisms (along paths). The mentioned quantities are connected by a number of relations derived in this work. In this third part of our series we investigate the bundle analogues of the conventional pictures of motion. In particular, there are found the state sections and bundle morphisms corresponding to state vectors and observables respectively. The equations of motion for these quantities are derived too. Using the results obtained, we consider from the bundle view-point problems concerning the integrals of motion. An invariant (bundle) necessary and sufficient conditions for a dynamical variable to be an integral of motion are found.Comment: 19 standard (11pt, A4) LaTeX 2e pages. The packages AMS-LaTeX and amsfonts are required. New references and comments are added. Minor style chages. Continuation of quant-ph/9803083, quant-ph/9803084 and quant-ph/9804062. For continuation of the series view http://www.inrne.bas.bg/mathmod/bozhome

    Fibre bundle formulation of nonrelativistic quantum mechanics. 0. Preliminary considerations: Quantum mechanics from a geometric-observer's viewpoint

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    We propose a version of the non-relativistic quantum mechanics in which the pure states of a quantum system are described as sections of a Hilbert (generally infinitely-dimensional) fibre bundle over the space-time. There evolution is governed via (a kind of) a parallel transport in this bundle. Some problems concerning observables are considered. There are derived the equations of motion for the state sections and observables. We show that up to a constant the matrix of the coefficients of the evolution operator (transport) coincides with the matrix of the Hamiltonian of the investigated quantum system.Comment: 15 standard LaTeX 2e (11pt, A4) pages. The packages AMS-LaTeX and amsfonts are require

    Fibre bundle formulation of relativistic quantum mechanics. I. Time-dependent approach

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    We propose a new fibre bundle formulation of the mathematical base of relativistic quantum mechanics. At the present stage the bundle form of the theory is equivalent to its conventional one, but it admits new types of generalizations in different directions. In the present first part of our investigation we consider the time-dependent or Hamiltonian approach to bundle description of relativistic quantum mechanics. In it the wavefunctions are replaced by (state) liftings of paths or sections along paths of a suitably chosen vector bundle over space-time whose (standard) fibre is the space of the wavefunctions. Now the quantum evolution is described as a linear transportation (by means of the evolution transport along paths in the space-time) of the state liftings/sections in the (total) bundle space. The equations of these transportations turn to be the bundle versions of the corresponding relativistic wave equations.Comment: 16 standard LaTeX pages. The packages AMS-LaTeX and amsfonts are required. The paper continuous the application of fibre bundle formalism to quantum physics began in the series of works quant-ph/9803083, quant-ph/9803084, quant-ph/9804062, quant-ph/9806046, quant-ph/9901039, quant-ph/9902068, and quant-ph/0004041. For related papers, view http://theo.inrne.bas.bg/~bozho

    Raman and Infrared-Active Phonons in Hexagonal HoMnO3_3 Single Crystals: Magnetic Ordering Effects

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    Polarized Raman scattering and infrared reflection spectra of hexagonal HoMnO3_3 single crystals in the temperature range 10-300 K are reported. Group-theoretical analysis is performed and scattering selection rules for the second order scattering processes are presented. Based on the results of lattice dynamics calculations, performed within the shell model, the observed lines in the spectra are assigned to definite lattice vibrations. The magnetic ordering of Mn ions, which occurs below TN_N=76 K, is shown to effect both Raman- and infrared-active phonons, which modulate Mn-O-Mn bonds and, consequently, Mn exchange interaction.Comment: 8 pages, 6 figure

    Solitons and Almost-Intertwining Matrices

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    We define the set of almost-intertwining matrices to be all triples(X,Y,Z) of n x n matrices for which XZ=YX+T for some rank one matrix T. A surprisingly simple formula is given for tau-functions of the KP hierarchy in terms of such triples. The tau-functions produced in this way include the soliton and vanishing rational solutions. The induced dynamics of the eigenvalues of the matrix X are considered, leading in special cases to the Ruijsenaars-Schneider particle system

    Asteroseismology of the {\it Kepler} target KIC\,9204718

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    The high precision data obtained by the {\it Kepler} satellite allows us to detect hybrid type pulsator candidates more accurately than the data obtained by ground-based observations. In this study, we present preliminary results on the new analysis of the {\it Kepler} light curve and high resolution spectroscopic observations of pulsating Am star KIC\,9204718. Our tentative analysis therefore show that the star has hybrid pulsational characteristics.Comment: 'Proceedings of Wide Field variability surveys : a 21 st Century 22nd Los Alamos Stellar Pulsation Conference San Pedro De Atacama ,Chile Nov 28-Dec 2, 2016' to be published by the EPJ Web of Conference

    START: Smoothed particle hydrodynamics with tree-based accelerated radiative transfer

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    We present a novel radiation hydrodynamics code, START, which is a smoothed particle hydrodynamics (SPH) scheme coupled with accelerated radiative transfer. The basic idea for the acceleration of radiative transfer is parallel to the tree algorithm that is hitherto used to speed up the gravitational force calculation in an N-body system. It is demonstrated that the radiative transfer calculations can be dramatically accelerated, where the computational time is scaled as Np log Ns for Np SPH particles and Ns radiation sources. Such acceleration allows us to readily include not only numerous sources but also scattering photons, even if the total number of radiation sources is comparable to that of SPH particles. Here, a test simulation is presented for a multiple source problem, where the results with START are compared to those with a radiation SPH code without tree-based acceleration. We find that the results agree well with each other if we set the tolerance parameter as < 1.0, and then it demonstrates that START can solve radiative transfer faster without reducing the accuracy. One of important applications with START is to solve the transfer of diffuse ionizing photons, where each SPH particle is regarded as an emitter. To illustrate the competence of START, we simulate the shadowing effect by dense clumps around an ionizing source. As a result, it is found that the erosion of shadows by diffuse recombination photons can be solved. Such an effect is of great significance to reveal the cosmic reionization process.Comment: 14 pages, 23 figures, accepted for publication in MNRA

    Phonons and Magnetic Excitations in Mott-Insulator LaTiO3_3

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    The polarized Raman spectra of stoichiometric LaTiO3_3 (TN=150_N = 150 K) were measured between 6 and 300 K. In contrast to earlier report on half-metallic LaTiO3.02_{3.02}, neither strong background scattering, nor Fano shape of the Raman lines was observed. The high frequency phonon line at 655 cm1^{-1} exhibits anomalous softening below TN_N: a signature for structural rearrangement. The assignment of the Raman lines was done by comparison to the calculations of lattice dynamics and the nature of structural changes upon magnetic ordering are discussed. The broad Raman band, which appears in the antiferromagnetic phase, is assigned to two-magnon scattering. The estimated superexchange constant J=15.4±0.5J = 15.4\pm0.5 meV is in excellent agreement with the result of neutron scattering studies.Comment: 4 pages, 5 figure
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