1,896 research outputs found

    Hohenberg-Kohn theorem for the lowest-energy resonance of unbound systems

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    We show that under well-defined conditions the Hohenberg-Kohn theorem (HKT) can be extended to the lowest-energy resonance of unbound systems. Using the Gel'fand Levitan theorem, the extended version of the HKT can also be applied to systems that support a finite number of bound states. The extended version of the HKT provides an adequate framework to carry out DFT calculations of negative electron affinities.Comment: 4 pages, 3 figure

    More on coupling coefficients for the most degenerate representations of SO(n)

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    We present explicit closed-form expressions for the general group-theoretical factor appearing in the alpha-topology of a high-temperature expansion of SO(n)-symmetric lattice models. This object, which is closely related to 6j-symbols for the most degenerate representation of SO(n), is discussed in detail.Comment: 9 pages including 1 table, uses IOP macros Update of Introduction and Discussion, References adde

    Coherent states for polynomial su(1,1) algebra and a conditionally solvable system

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    In a previous paper [{\it J. Phys. A: Math. Theor.} {\bf 40} (2007) 11105], we constructed a class of coherent states for a polynomially deformed su(2)su(2) algebra. In this paper, we first prepare the discrete representations of the nonlinearly deformed su(1,1)su(1,1) algebra. Then we extend the previous procedure to construct a discrete class of coherent states for a polynomial su(1,1) algebra which contains the Barut-Girardello set and the Perelomov set of the SU(1,1) coherent states as special cases. We also construct coherent states for the cubic algebra related to the conditionally solvable radial oscillator problem.Comment: 2 figure

    Supersymmetry solution for finitely extensible dumbbell model

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    Exact relaxation times and eigenfunctions for a simple mechanical model of polymer dynamics are obtained using supersymmetry methods of quantum mechanics. The model includes the finite extensibility of the molecule and does not make use of the self-consistently averaging approximation. The finite extensibility reduces the relaxation times when compared to a linear force. The linear viscoelastic behaviour is obtained in the form of the ``generalized Maxwell model''. Using these results, a numerical integration scheme is proposed in the presence of a given flow kinematics.Comment: 5 pages, 2 figure

    Investigating the effectiveness of a comprehensive literacy coaching program in schools with high teacher mobility

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    Teacher mobility is a factor that impacts schoolwide implementation of professional development programs. In this article, we present interim results of a longitudinal randomized field trial of a comprehensive literacy coaching program (Content-Focused Coaching, CFC) for improving instruction and learning in schools with high teacher mobility.Weinvestigate program effects on 73 new treatment and comparison teachers recruited to replace the large proportion of teachers who left their schools during the first year of the program. HLM analyses indicated that the CFC program predicted significantly higher school-level gains on the state standardized test for English language learners (N=496, ES=.51). By spring, the quality of teachers' self-reported and observed instruction in the CFC schools exceeded that of comparison teachers. Implications for accommodating new teachers into an ongoing and established coaching program to improve instruction and student learning, and conducting randomized trials in schools with high teacher turnover, are discussed. Copyright © 2010 by The University of Chicago

    Shell-Model Effective Operators for Muon Capture in ^{20}Ne

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    It has been proposed that the discrepancy between the partially-conserved axial-current prediction and the nuclear shell-model calculations of the ratio CP/CAC_P/C_A in the muon-capture reactions can be solved in the case of ^{28}Si by introducing effective transition operators. Recently there has been experimental interest in measuring the needed angular correlations also in ^{20}Ne. Inspired by this, we have performed a shell-model analysis employing effective transition operators in the shell-model formalism for the transition 20Ne(0g.s.+)+μ20F(1+;1.057MeV)+νμ^{20}Ne(0^+_{g.s.})+\mu^- \to ^{20}F(1^+; 1.057 MeV) + \nu_\mu. Comparison of the calculated capture rates with existing data supports the use of effective transition operators. Based on our calculations, as soon as the experimental anisotropy data becomes available, the limits for the ratio CP/CAC_P/ C_A can be extracted.Comment: 9 pages, 3 figures include

    Isospectrality of conventional and new extended potentials, second-order supersymmetry and role of PT symmetry

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    We develop a systematic approach to construct novel completely solvable rational potentials. Second-order supersymmetric quantum mechanics dictates the latter to be isospectral to some well-studied quantum systems. PT\cal PT symmetry may facilitate reconciling our approach to the requirement that the rationally-extended potentials be singularity free. Some examples are shown.Comment: 13 pages, no figure, some additions to introduction and conclusion, 4 more references; to be published in Special issue of Pramana - J. Phy

    The classical supersymmetric Coulomb problem

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    After setting up a general model for supersymmetric classical mechanics in more than one dimension we describe systems with centrally symmetric potentials and their Poisson algebra. We then apply this information to the investigation and solution of the supersymmetric Coulomb problem, specified by an 1/|x| repulsive bosonic potential.Comment: 25 pages, 2 figures; reference added, some minor modification

    Antibody-related movement disorders - a comprehensive review of phenotype-autoantibody correlations and a guide to testing

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    Background: Over the past decade increasing scientific progress in the field of autoantibody–mediated neurological diseases was achieved. Movement disorders are a frequent and often prominent feature in such diseases which are potentially treatable. Main body: Antibody-mediated movement disorders encompass a large clinical spectrum of diverse neurologic disorders occurring either in isolation or accompanying more complex autoimmune encephalopathic diseases. Since autoimmune movement disorders can easily be misdiagnosed as neurodegenerative or metabolic conditions, appropriate immunotherapy can be delayed or even missed. Recognition of typical clinical patterns is important to reach the correct diagnosis. Conclusion: There is a growing number of newly discovered antibodies which can cause movement disorders. Several antibodies can cause distinctive phenotypes of movement disorders which are important to be aware of. Early diagnosis is important because immunotherapy can result in major improvement. In this review article we summarize the current knowledge of autoimmune movement disorders from a point of view focused on clinical syndromes. We discuss associated clinical phenomenology and antineuronal antibodies together with alternative etiologies with the aim of providing a diagnostic framework for clinicians considering underlying autoimmunity in patients with movement disorders

    Are N=1 and N=2 supersymmetric quantum mechanics equivalent?

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    After recalling different formulations of the definition of supersymmetric quantum mechanics given in the literature, we discuss the relationships between them in order to provide an answer to the question raised in the title.Comment: 15 page
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