49,111 research outputs found

    Study of Strangeness Condensation by Expanding About the Fixed Point of the Harada-Yamawaki Vector Manifestation

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    Building on, and extending, the result of a higher-order in-medium chiral perturbation theory combined with renormalization group arguments and a variety of observations of the vector manifestation of Harada-Yamawaki hidden local symmetry theory, we obtain a surprisingly simple description of kaon condensation by fluctuating around the "vector manifestation (VM)" fixed point identified to be the chiral restoration point. Our development establishes that strangeness condensation takes place at about 3 n_0 where n_0 is nuclear matter density. This result depends only on the renoramlization-group (RG) behavior of the vector interactions, other effects involved in fluctuating about the bare vacuum in so many previous calculations being "irrelevant" in the RG about the fixed point. Our results have major effects on the collapse of neutron stars into black holes.Comment: 4 page

    Dilatons for Dense Hadronic Matter

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    The idea that the explicit breaking of scale invariance by the trace anomaly of QCD can be rephrased as a spontaneous breaking has been recently exploited to capture the low-energy strong interaction dynamics of dense (and also hot) matter in terms of two dilaton fields, the "soft" (chi_s) and the "hard" (chi_h) fields, in the frame work of the hidden local gauge symmetry. In the Freund-Nambu model, the spontaneous symmetry breaking of scale symmetry is induced by an explicitly breaking term, while the spontaneous symmetry breaking is possible in the flat potential model which is scale symmetric. We discuss the interplay of the soft and hard dilatons using the spontaneously broken scale symmetry schemes and uncover a novel structure of dense matter hitherto unexplored.Comment: 7 pages, Invited talks presented at 4th International Conference on Symmetres in Subatomic Physics, June 2-5, 2009, Taipei, Taiwa

    Presure-Induced Superconducting State of Antiferromagnetic CaFe2_2As2_2

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    The antiferromagnet CaFe2_2As2_2 does not become superconducting when subject to ideal hydrostatic pressure conditions, where crystallographic and magnetic states also are well defined. By measuring electrical resistivity and magnetic susceptibility under quasi-hydrostatic pressure, however, we find that a substantial volume fraction of the sample is superconducting in a narrow pressure range where collapsed tetragonal and orthorhombic structures coexist. At higher pressures, the collapsed tetragonal structure is stabilized, with the boundary between this structure and the phase of coexisting structures strongly dependent on pressure history. Fluctuations in magnetic degrees of freedom in the phase of coexisting structures appear to be important for superconductivity.Comment: revised (6 pages, 5 figures) - includes additional experimental result

    A collective scattering system for measuring electron gyroscale fluctuations on the National Spherical Torus Experiment

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    A collective scattering system has been installed on the National Spherical Torus Experiment (NSTX) to measure electron gyroscale fluctuations in NSTX plasmas. The system measures fluctuations with k(perpendicular to)rho(e)less than or similar to 0.6 and k(perpendicular to)less than or similar to 20 cm(-1). Up to five distinct wavenumbers are measured simultaneously, and the large toroidal curvature of NSTX plasmas provides enhanced spatial localization. Steerable optics can position the scattering volume throughout the plasma from the magnetic axis to the outboard edge. Initial measurements indicate rich turbulent dynamics on the electron gyroscale. The system will be a valuable tool for investigating the connection between electron temperature gradient turbulence and electron thermal transport in NSTX plasmas.X1137sciescopu

    Automatic Dimension Selection for a Non-negative Factorization Approach to Clustering Multiple Random Graphs

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    We consider a problem of grouping multiple graphs into several clusters using singular value thesholding and non-negative factorization. We derive a model selection information criterion to estimate the number of clusters. We demonstrate our approach using "Swimmer data set" as well as simulated data set, and compare its performance with two standard clustering algorithms.Comment: This paper has been withdrawn by the author due to a newer version with overlapping content

    Influences of an impurity on the transport properties of one-dimensional antisymmetric spin filter

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    The influences of an impurity on the spin and the charge transport of one-dimensional antisymmetric spin filter are investigated using bosonization and Keldysh formulation and the results are highlighted against those of spinful Luttinger liquids. Due to the dependence of the electron spin orientation on wave number the spin transport is not affected by the impurity, while the charge transport is essentially identical with that of spinless one-dimensional Luttinger liquid.Comment: 7 pages, 2 figures. To appear in Physical Review

    Holographic Meson Spectra in the Dense Medium with Chiral Condensate

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    We study two 1/Nc1/N_c effects on the meson spectra by using the AdS/CFT correspondence where the 1/Nc1/N_c corrections from the chiral condensate and the quark density are controlled by the gravitational backreaction of the massive scalar field and U(1) gauge field respectively. The dual geometries with zero and nonzero current quark masses are obtained numerically. We discuss meson spectra and binding energy of heavy quarkonium with the subleading corrections in the hard wall model.Comment: 16 pages, 4 figure

    Balancing the power of multimedia information retrieval and usability in designing interactive TV

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    Steady progress in the field of multimedia information retrieval (MMIR) promises a useful set of tools that could provide new usage scenarios and features to enhance the user experience in today s digital media applications. In the interactive TV domain, the simplicity of interaction is more crucial than in any other digital media domain and ultimately determines the success or otherwise of any new applications. Thus when integrating emerging tools like MMIR into interactive TV, the increase in interface complexity and sophistication resulting from these features can easily reduce its actual usability. In this paper we describe a design strategy we developed as a result of our e®ort in balancing the power of emerging multimedia information retrieval techniques and maintaining the simplicity of the interface in interactive TV. By providing multiple levels of interface sophistication in increasing order as a viewer repeatedly presses the same button on their remote control, we provide a layered interface that can accommodate viewers requiring varying degrees of power and simplicity. A series of screen shots from the system we have actually developed and built illustrates how this is achieved
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