Tue·Oct 25, 2005Tuesday·October 25, 2005

1. 01*

   Overlap fermion with the topology conserving gauge action

   H. Fukaya🇯🇵 · S. Hashimoto🇯🇵 · T. Hirohashi🇯🇵 · H. Matsufuru🇯🇵 · K. Ogawa🇯🇵 · T. Onogi🇯🇵

   We investigate the distribution of low-lying eigenmodes of hermitian Wilson-Dirac operator, $H_W$, with the gauge action whose form is designed to avoid topology change, as well as with the standard plaquette action. On the quenched lattices, the former gauge action exhibits less density of low-lying eigenmodes of $H_W$ compared to the latter at the same lattice spacing. We also show preliminary results for the dynamical simulation with two flavors of overlap fermions.

   hep-latPoS(2006)·3 citations
2. 02*

   Kaon B-parameter with NF=2 dynamical Wilson fermions

   F.Mescia🇮🇹 · V.Gimenez🇪🇸 · V.Lubicz🇮🇹 · G.Martinelli🇮🇹 · S.Simula🇮🇹 · C.Tarantino🇮🇹

   We present a preliminary study of the neutral kaon mixing bag parameter BK using two flavors of dynamical Wilson fermions. We determine the matrix element of the relevant DeltaS=2 operator by using both the conventional approach and the so called ``non-subtraction method'', and find that the latter leads to results with smaller uncertainties. After having implemented non-perturbative renormalization, we study the dependence of BK on the see quark mass. At our relatively heavy values of quark masses (0.60<M_P/M_V<0.75) such a dependence is found to be negligible and the results, within the statistical accuracy, are consistent with a quenched determination. As a preliminary result for the renormalization group invariant parameter we quote BKRGI=1.02(25).

   hep-latPoS(2006)·9 citations
3. 03*

   Eigenmodes of covariant Laplacian in SU(2) Yang-Mills vacuum: higher representations

   J. Greensite🇺🇸 · S. Olejnik🇸🇰 · M. I. Polikarpov🇷🇺 · S. N. Syritsyn🇷🇺 · V. I. Zakharov🇩🇪

   The study of lowest eigenmodes of the covariant Laplacian in fundamental representation of the gauge group revealed their specific localization properties. These may bear information on confinement of fundamental scalar particles in SU(2) Yang-Mills vacuum. It was expected that scalar particle eigenmodes in other representations would be localized in different physical volumes. However simulations show strikingly different results for the adjoint and higher (J=3/2) representations. Apart from much higher extent of localization, we find evidence of different scaling behavior of localized eigenmodes.

   hep-latPoS(2006)·3 citations
4. 04*

   Localization of Low Lying Eigenmodes for Chirally Symmetric Dirac Operator

   M.I. Polikarpov🇷🇺 · F.V. Gubarev🇷🇺 · S.M. Morozov🇷🇺 · V.I. Zakharov🇩🇪

   We consider properties of zero and near-zero modes for overlap fermion operator in SU(2) lattice gluodynamics. The density of the states is of the order of Lambda(QCD) while the localization volume of the modes tends to zero in physical units with the lattice spacing tending to zero. The situation changes drastically when we study "vortex removed" configurations.

   hep-latPoS(2006)·15 citations
5. 05*

   Vortex Proliferation and the Dual Superconductor Scenario for Confinement: The 3D Compact U(1) Lattice Higgs Model

   Sandro Wenzel🇩🇪 · Elmar Bittner🇩🇪 · Wolfhard Janke🇩🇪 · Adriaan M.J. Schakel🇩🇪 · Arwed Schiller🇩🇪

   It is argued that the phase diagram of the 3D Compact U(1) Lattice Higgs Model is more refined than generally thought. The confined and Higgs phases are separated by a well-defined phase boundary, marked by proliferating vortices. It is shown that the confinement mechanism at work is precisely the dual superconductor scenario.

   hep-latPoS(2006)·2 citations
6. 06*

   Transport Coefficient of Gluon Plasma from Lattice QCD

   Sunao Sakai🇯🇵 · Atsushi Nakamura🇯🇵

   In this report we present our calculation of the transport coefficient of gluon system on $24^3\times 8$ lattice in the quench approximation. Simulations are carried out in the range, $1.4\le T/T_c\le 24$. In the temperature region slightly above the transition, where the perturbative calculation is not applicable, the shear viscosity($\eta$) is smaller than typical hadron masses. The bulk viscosity is consistent with zero within the range of error bars in $1.4\le T/T_c\le 24$. We compare our results with the perturbative calculations in large $T/T_c$ region. It is found that the lattice and perturbative results are consistent with each other there. The ratio $\eta /s$ is around $0.1-0.4$ in $T/T_c<3$ region and satisfies the KSS bound\cite{KSS}. In order to estimate the contribution from high frequency part of the spectral function, we study the effects of a term ${\rho }^{high}$ proposed by Aarts and Resco\cite{Aarts}. It is found that until the threshold mass becomes small, its effect is quite small, and that viscosity decreases as the threshold decreases. From these studies we think that although our result is obtained under an assumptions for the spectral function, it gives a reasonable estimation for $\eta$($=\pi d\rho /d\omega$ at $\omega =0$), and qualitative results will not be changed when the accurate spectral function is obtained.

   hep-latPoS(2006)·10 citations
7. 07*

   Loop States in Lattice Gauge Theories

   Manu Mathur🇮🇳

   We solve the Gauss law as well as the corresponding Mandelstam constraints of (d+1) dimensional SU(2) lattice gauge theory in terms of harmonic oscillator prepotentials. This enables us to explicitly construct a complete orthonormal and manifestly gauge invariant basis in the physical Hilbert space. Further, we show that this gauge invariant description represents networks of unoriented loops carrying certain non-negative abelian fluxes created by the harmonic oscillator prepotentials. The loop network is characterized by $3(d-1)$ gauge invariant integers at every lattice site which is the number of physical degrees of freedom. Time evolution involves local fluctuations of these loops. The loop Hamiltonian is derived. The generalization to SU(N) gauge group is discussed.

   hep-lathep-thPLB(2006)·46 citations

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.