1,311 research outputs found

    Long-distance behavior of qqˉq\bar{q} color dependent potentials at finite temperature

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    SU(3) heavy quark potentials at finite temperature are studied with quenched lattice QCD using the stochastic gauge-fixing method. In addition to the standard color average channel, we investigate qqˉq\bar{q} potentials in singlet and octet channels. % We obtain clear signals in all cases. The singlet qqˉq\bar{q} channel yields an attractive force, while the octet qqˉq\bar{q} potential is repulsive; the corresponding color average channel also results in an attractive force. %As the temperature increases, these forces are weakened and As the temperature increases, these forces become weak and their variations are very small; at T/Tc=1.8−5.6T/T_c=1.8-5.6, % the singlet attractive force is not so weakened even for long distances. the singlet attractive force survives over R∼1/TR \sim 1/T. The singlet and octet potentials calculated with this algorithm have a small gauge dependence when the gauge parameter α\alpha is changed from 0.6 to 1.3.Comment: 12 pages, 9 figures, typos corrected, to appear in Prog. Theor. Phy

    Stratified Ehrhart ring theory on periodic graphs

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    We investigate the "stratified Ehrhart ring theory" for periodic graphs, which gives an algorithm for determining the growth sequences of periodic graphs. The growth sequence (sΓ,x0,i)i≥0(s_{\Gamma, x_0, i})_{i \ge 0} is defined for a graph Γ\Gamma and its fixed vertex x0x_0, where sΓ,x0,is_{\Gamma, x_0, i} is defined as the number of vertices of Γ\Gamma at distance ii from x0x_0. Although the sequences (sΓ,x0,i)i≥0(s_{\Gamma, x_0, i})_{i \ge 0} for periodic graphs are known to be of quasi-polynomial type, their determination had not been established, even in dimension two. Our algorithm and the proofs are based on algebraic combinatorics, analogous to the Ehrhart theory. As an application of the algorithm, we determine the growth sequences in several new examples.Comment: 46 pages. arXiv admin note: text overlap with arXiv:2305.0817

    Local density of states and superconducting gap in the iron chalcogenide superconductor Fe1+δ_{1+\delta}Se1−x_{1-x}Tex_{x} observed by scanning tunneling spectroscopy

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    We report on the first investigation of the quasiparticle local density of states and superconducting gap in the iron chalcogenide superconductor Fe1+δ_{1+\delta}Se1−x_{1-x}Tex_{x} (Tc∼14T_{\mathrm{c}} \sim 14 K). The surface of a cleaved crystal revealed an atomic square lattice, superimposed on the inhomogeneous background, with a lattice constant of ∼3.8\sim 3.8 \AA without any reconstruction. Tunneling spectra measured at 4.2 K exhibit the superconducting gap, which completely disappears at 18 K, with a magnitude of ∼2.3\sim 2.3 meV, corresponding to 2Δ/kBTc=3.82\Delta / k_{\mathrm{B}}T_{\mathrm{c}}=3.8.In stark contrast to the cuprate superconductors, the value of the observed superconducting gap is relatively homogeneous, following a sharp distribution with a small standard deviation of 0.23 meV. Conversely, the normal-state local density of states observed above TcT_{\mathrm{c}} shows spatial variation over a wide energy range of more than 1 eV, probably due to the excess iron present in the crystal.Comment: 4 pages, 5 figure

    A French Corpus Annotated for Multiword Nouns

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    International audienceThis paper presents a French corpus annotated for multiword nouns. This corpus is designed for investigation in information retrieval and extraction, as well as in deep and shallow syntactic parsing. We delimit which kind of multiword units we targeted for this annotation task; we describe the resources and methods we used for the annotation; and we briefly comment on the results. The annotated corpus is available at http://infolingu.univ-mlv.fr/ under the LGPLLR license.Cet article présente un corpus du français muni d'annotations sur les noms composés. Ce corpus est conçu pour la recherche sur l'extraction d'informations ainsi que sur l'analyse syntaxique superficielle ou profonde. Nous délimitons quels types de mots composés nous avons ciblés pour cette tâche d'annotation ; nous décrivons les ressources et les méthodes que nous avons utilisées pour l'annotation ; et nous commentons brièvement les résultats. Le corpus annoté est disponible sur http://infolingu.univ-mlv.fr/ sous licence LGPLLR

    Vers la création d'un Verbnet du français

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    International audienceVerbNet est une ressource lexicale pour les verbes anglais qui est bien utile pour le TAL grâce à sa large couverture et sa classification cohérente. Une telle ressource n'existe pas pour le français malgré quelques tentatives. Nous montrons comment adapter semi-automatiquement VerbNet en utilisant deux ressources lexicales existantes, le LVF (Les Verbes Français) et le LG (Lexique-Grammaire). Abstract. VerbNet is an English lexical resource that has proven useful for NLP due to its high coverage and coherent classification. Such a resource doesn't exist for French, despite some (mostly automatic and unsupervised) at-tempts. We show how to semi-automatically adapt VerbNet using existing lexical resources, namely LVF (Les Verbes Français) and LG (Lexique-Grammaire). Mots-clés : VerbNet, cadres de sous-catégorisations, rôles sémantiques
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