10,264 research outputs found

    Recent results from Lattice QCD

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    Recent Lattice QCD results are reviewed with an emphasis on spectroscopic results concerning the charm quark. It is demonstrated that, with accurate computations from lattice QCD in recent years that can be compared with the existing or upcoming experiments, stringent test of the Standard Model can be performed which will greatly sharpen our knowledge on the strong interaction.Comment: 12 pages, 5 figures. Plenary talk presented at The XXXIII international symposium on Physics in Collision (PIC2013), Institute of High Energy Physics, Beijing, P. R. China, 03 - 07 September 201

    Implementation of Symanzik's Improvement Program for Simulations of Dynamical Wilson Fermions in Lattice QCD

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    We discuss the implementation of a Sheikholeslami-Wohlert term for simulations of lattice QCD with dynamical Wilson fermions as required by Symanzik's improvement program. We show that for the Hybrid Monte Carlo or Kramers equation algorithm standard even-odd preconditioning can be maintained. We design tests of the implementation using analytically and numerically computed cumulant expansions. We find that, for situations where the average number of Conjugate Gradient iterations exceeds 200, the overhead is only about 20%.Comment: uuencoded gzipped tar-file, Latex2e source file, 6 Figures, 22 pages, one reference adde

    A Mean-field Calculation for the Three-Dimensional Holstein Model

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    A path integral representation appropriate for further Monte Carlo simulations is derived for the electron-phonon Holstein model in three spatial dimensions. The model is studied within mean-field theory. Charge density wave and superconducting phase transitions are discussed.Comment: Latex file typeset using elsart.cls, 16 pages, 2 figures, submitted to Journal of Physics: Condensed Matte

    On paratopological groups

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    In this paper, we firstly construct a Hausdorff non-submetrizable paratopological group GG in which every point is a GδG_{\delta}-set, which gives a negative answer to Arhangel'ski\v{\i}\ and Tkachenko's question [Topological Groups and Related Structures, Atlantis Press and World Sci., 2008]. We prove that each first-countable Abelian paratopological group is submetrizable. Moreover, we discuss developable paratopological groups and construct a non-metrizable, Moore paratopological group. Further, we prove that a regular, countable, locally kωk_{\omega}-paratopological group is a discrete topological group or contains a closed copy of SωS_{\omega}. Finally, we discuss some properties on non-H-closed paratopological groups, and show that Sorgenfrey line is not H-closed, which gives a negative answer to Arhangel'ski\v{\i}\ and Tkachenko's question [Topological Groups and Related Structures, Atlantis Press and World Sci., 2008]. Some questions are posed.Comment: 14 page
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