4,156 research outputs found

    Feshbach resonance scattering under cylindrical harmonic confinement

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    A problem of collisions of atoms with two-channel zero-range interaction in an atomic waveguide is solved by using of a renormalization procedure. A matching of the solution to a solution of the related one-dimensional problem leads to relation between the one-dimensional and three-dimensional scattering parameters. The scattering amplitude and bound states for the confined system demonstrate differences from the related free and one-dimensional systems.Comment: Completely rewritten version,8 pages with 5 figures, uses REVTe

    On quantization of nondispersive wave packets

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    Canonical commutation relations for the Bateman-Hillion type nondispersive wave packets are constructedComment: LaTeX, 10 page

    Any l-state analytical solutions of the Klein-Gordon equation for the Woods-Saxon potential

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    The radial part of the Klein-Gordon equation for the Woods-Saxon potential is solved. In our calculations, we have applied the Nikiforov-Uvarov method by using the Pekeris approximation to the centrifugal potential for any ll states. The exact bound state energy eigenvalues and the corresponding eigenfunctions are obtained on the various values of the quantum numbers nn and ll. The non-relativistic limit of the bound state energy spectrum was also found.Comment: 15 pages, 1 tabl

    The nature and function of the categories in the philosophy of Immanuel Kant, James Ward, S. Alexander

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    The aim of this investigation is to discuss the merits of the three radically divergent views as to the nature and function of the categories held by Kant, Ward and Alexander.The scope of the study is expressly limited to considerations and problems of a general nature with reference to the epistemo-logical categories. Consequently, if, as some maintain, there are categories unique to the several sciences, our discussion may be described as confined to the categories of Consciousness. It is, therefore, not directly concerned with such subsidiary problems as the number of the categories, or the status of unique categories in such special sciences as morality and aesthetics.These delimitations of the problem require no apology. They are justified on the methodological principle that the basic issues of a problem should be thoroughly investigated and clearly defined before embarking on subsidiary questions.This subject was suggested some years ago by the very cavalier treatment of a priori categories in most contemporary thought. The recent appearance of several works giving explicit attention to the nature of the categories is a gratifying assurance that the problem is not a dead issue.The somewhat lengthy discussion of Kant is due (i) to the sharing of Professor Alexander's conviction "that with or after Plato there is nothing comparable in importance upon this subject with what may be learned from him,"; (ii) Exposition of Kant must be supported by detailed and extensive evidence in view of the conflicts of doctrine in the master himself, and the divergencies of interpretation among his expositors.In tracing the growth and development of the Kantian theory of categories in the seventies, the dating of the Reflexionen by Adickes in the Berlin edition is assumed as authoritative

    Non-perturbative solutions in the electro-weak theory with tˉt\bar t t condensate and the tt-quark mass

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    We apply Bogoliubov compensation principle to the gauge electro-weak interaction to demonstrate a spontaneous generation of anomalous three-boson gauge invariant effective interaction. The non-trivial solution of compensation equations uniquely defines the form-factor of the anomalous interaction and parameters of the theory including value of gauge electro-weak coupling g(MW2)g(M_W^2) in satisfactory agreement with its experimental value. A possibility of spontaneous generation of effective four-fermion interaction of heavy quarks is also demonstrated. This interaction defines an equation for a scalar bound state of heavy quarks which serve as a substitute for the elementary scalar Higgs doublet. As a result we calculate the tt-quark mass mt = 177 GeVm_t\,=\,177\,GeV in satisfactory agreement with the experimental value. The results strongly support idea of tˉ t\bar t\,t condensate as a source of the electro-weak symmetry breaking.Comment: 16 pages, 5 figures. arXiv admin note: substantial overlap with arXiv:1103.395

    CDF Wjj anomaly as a non-perturbative effect of the electro-weak interaction

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    The recently reported CDF excess at 120 − 160 GeV120\,-\, 160\,GeV in invariant mass distribution of jet pairs accompanying WW-boson is tentatively interpreted as a bound state of two WW decaying to quark-anti-quark pair. Non-perturbative effects of EW interaction obtained by application of Bogoliubov compensation approach lead to such bound state due to existence of anomalous three-boson gauge-invariant effective interaction. The application of this scheme gives satisfactory agreement with existing data without any adjusting parameter but the bound state mass 145 GeV145\,GeV.Comment: 5 pages, 2 figure

    Pair creation by a photon in a strong magnetic field

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    The process of pair creation by a photon in a strong magnetic field is investigated basing on the polarization operator in the field. The total probability of the process is found in a relatively simple form. The probability exhibits a "saw-tooth" pattern because of divergences arising when the electron and positron are created at threshold of the Landau energy levels. The pattern will be washed out at averaging over any smooth photon energy distribution. The new results are obtained in the scope of the quasiclassical approach: 1) in the case when the magnetic field B≪B0,(B0B \ll B_0, (B_0 is the critical field) the new formulation extends the photon energy interval to the case when the created particles are not ultrarelativistic; 2) the correction to the standard quasiclassical approximation is found showing the range of applicability of the approach at high photon energy as well. The very important conclusion is that for both cases B≪B0B \ll B_0 and B≥B0B \geq B_0 the results of the quasiclassical calculation are very close to averaged probabilities of exact theory in a very wide range of photon energies. The quasiclassical approximation is valid also for the energy distribution if the electron and positron are created on enough high levels.Comment: 21 pages, 6 figure

    HIV infection and domestic smoke exposure, but not human papillomavirus, are risk factors for esophageal squamous cell carcinoma in Zambia: a case-control study

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    (c) 2015 The Authors. Cancer Medicine published by John Wiley & Sons Ltd. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited

    Dynamic properties of the spin-1/2 XY chain with three-site interactions

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    We consider a spin-1/2 XY chain in a transverse (z) field with multi-site interactions. The additional terms introduced into the Hamiltonian involve products of spin components related to three adjacent sites. A Jordan-Wigner transformation leads to a simple bilinear Fermi form for the resulting Hamiltonian and hence the spin model admits a rigorous analysis. We point out the close relationships between several variants of the model which were discussed separately in previous studies. The ground-state phases (ferromagnet and two kinds of spin liquid) of the model are reflected in the dynamic structure factors of the spin chains, which are the main focus in this study. First we consider the zz dynamic structure factor reporting for this quantity a closed-form expression and analyzing the properties of the two-fermion (particle-hole) excitation continuum which governs the dynamics of transverse spin component fluctuations and of some other local operator fluctuations. Then we examine the xx dynamic structure factor which is governed by many-fermion excitations, reporting both analytical and numerical results. We discuss some easily recognized features of the dynamic structure factors which are signatures for the presence of the three-site interactions.Comment: 28 pages, 10 fugure
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