Recent results from Lattice QCD

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

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

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

In this paper, we firstly construct a Hausdorff non-submetrizable paratopological group $G$ in which every point is a $G_{\delta}$-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 $k_{\omega}$-paratopological group is a discrete topological group or contains a closed copy of $S_{\omega}$. 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

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

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

KSS unit root test of nonlinearity and nonstationarity in China’s agricultural futures markets

AbstractUnit root tests are the starting points of most economic time series analyses. Based on the nonlinear unit root test proposed by Kapetanios, Shin and Shell (KSS), this article propose a procedure to detect the presence of nonstationarity against nonlinear processes in 5 representative China’s agricultural futures markets. Our results illustrate that a unit root is rejected in favor of nonlinear trend stationary for these markets; therefore, the results in current literature based on the linear hypothesis may be spurious in understanding true market’s dynamics. We contribute to current literature in providing for the first time the empirical evidence of these facts in China’s agricultural futures markets, which is fundamentally important in relevant researches