10,498 research outputs found

    Mass Spectra of N=2 Supersymmetric SU(n) Chern-Simons-Higgs Theories

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    An algebraic method is used to work out the mass spectra and symmetry breaking patterns of general vacuum states in N=2 supersymmetric SU(n) Chern-Simons-Higgs systems with the matter fields being in the adjoint representation. The approach provides with us a natural basis for fields, which will be useful for further studies in the self-dual solutions and quantum corrections. As the vacuum states satisfy the SU(2) algebra, it is not surprising to find that their spectra are closely related to that of angular momentum addition in quantum mechanics. The analysis can be easily generalized to other classical Lie groups.Comment: 17 pages, use revte

    The Chern-Simons Coefficient in Supersymmetric Non-abelian Chern-Simons Higgs Theories

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    By taking into account the effect of the would be Chern-Simons term, we calculate the quantum correction to the Chern-Simons coefficient in supersymmetric Chern-Simons Higgs theories with matter fields in the fundamental representation of SU(n). Because of supersymmetry, the corrections in the symmetric and Higgs phases are identical. In particular, the correction is vanishing for N=3 supersymmetric Chern-Simons Higgs theories. The result should be quite general, and have important implication for the more interesting case when the Higgs is in the adjoint representation.Comment: more references and explanation about rgularization dpendence are included, 13 pages, 1 figure, latex with revte

    Electronic structure and magnetic properties of epitaxial FeRh(001) ultra-thin films on W(100)

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    Epitaxial FeRh(100) films (CsCl structure, 10 ML \sim 10\ ML\ thick), prepared {\it in-situ} on a W(100) single crystal substrate, have been investigated via valence band and core level photoemission. The presence of the temperature-induced, first-order, antiferromagnetic to ferromagnetic (AF\rightarrow FM) transition in these films has been verified via linear dichroism in photoemission from the Fe 3pp levels. Core level spectra indicate a large moment on the Fe atom, practically unchanged in the FM and AF phases. Judging from the valence band spectra, the metamagnetic transition takes place without substantial modification of the electronic structure. In the FM phase, the spin-resolved spectra compare satisfactorily to the calculated spin-polarized bulk band structure.Comment: 7 pages, 5 figure

    Testing for instability in covariance structures

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    We propose a test for the stability over time of the covariance matrix of multivariate time series. The analysis is extended to the eigensystem to ascertain changes due to instability in the eigenvalues and/or eigenvectors. Using strong Invariance Principles and Law of Large Numbers, we normalise the CUSUM-type statistics to calculate their supremum over the whole sample. The power properties of the test versus alternative hypotheses, including also the case of breaks close to the beginning/end of sample are investigated theoretically and via simulation. We extend our theory to test for the stability of the covariance matrix of a multivariate regression model. The testing procedures are illustrated by studying the stability of the principal components of the term structure of 18 US interest rates

    Effects of thermal recycling temperatures on the reinforcement potential of glass fibers

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    In the present work the reinforcement potential of thermally recycled glass fibers in injection molded Polypropylene (PP) composites was investigated. Microbond tests showed that fiber sizing lost its compatibility to the PP matrix after exposure to temperatures of 250 °C in air. The drop of the adhesion between fibers and PP was mirrored by a large reduction of the tensile strength of the injection molded PP composites. In inert atmosphere the degradation of the fiber sizing and the reduction of the IFSS were less rapid than in air but no significant difference was observed above 400 °C. It was concluded that thermally recycled glass fibers will require a post-treatment to act as an effective reinforcement in injection molded PP composites even if the thermal recycling was performed in an inert atmosphere. The post-treatment will need to improve the compatibility of the fibers to the polymer matrix and the fiber strength

    Dynamic stability of a flexible booster subjected to a gimbled, periodically-varying end thrust Technical memorandum no. 104

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    Dynamic structural behavior of large rocket booster synthesized by two thin-walled cylinders and subjected to periodically varying end thrus

    Accountability and Relationship-Definition Among Food Banks Partnerships

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    Food pantries typically operate in a partnership structure where they are primarily supported by a larger food bank. However, the ability to execute that mission through cooperative arrangements greatly depends upon accountability, a key dynamic that ensures partners are fulfilling expectations and key roles. This exploratory study utilizes qualitative interview data (n = 61) from a large food bank network to understand the extent to which a lead agency (i.e., a large food bank) meets expectations of accountability among partners. The interview results demonstrate that the extent to which expectations are met relate to different types of relationships between the lead agency and partner members. Furthermore, the ways in which partners assess the strengths or weaknesses of the food bank’s accountability reveal different types of relationships within the network, namely that of supplier–customer, supporter–customer, and supporter–collaborator

    Janus Configurations, Chern-Simons Couplings, And The Theta-Angle in N=4 Super Yang-Mills Theory

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    We generalize the half-BPS Janus configuration of four-dimensional N=4 super Yang-Mills theory to allow the theta-angle, as well as the gauge coupling, to vary with position. We show that the existence of this generalization is closely related to the existence of novel three-dimensional Chern-Simons theories with N=4 supersymmetry. Another closely related problem, which we also elucidate, is the D3-NS5 system in the presence of a four-dimensional theta-angle.Comment: 66 p
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