858 research outputs found
Improving the Partial-Global Stochastic Metropolis Update for Dynamical Smeared Link Fermions
We discuss several methods that improve the partial-global stochastic
Metropolis (PGSM) algorithm for smeared link staggered fermions. We present
autocorrelation time measurements and argue that this update is feasible even
on reasonably large lattices.Comment: 3 pages, 3 figures, Lattice2002(algor
The role of heavy fermions
Heavy dynamical fermions with masses around the cut-off do not change the low
energy physics apart from a finite renormalization of the gauge coupling. In
this paper we study how light the heavy fermions have to be to cause more than
this trivial renormalization.Comment: uuencoded 3 page postscript contribution to Lattice 93, COLO-HEP-33
Non--perturbative tests of the fixed point action for SU(3) gauge theory
In this paper (the second of a series) we extend our calculation of a
classical fixed point action for lattice pure gauge theory to include
gauge configurations with large fluctuations. The action is parameterized in
terms of closed loops of link variables. We construct a few-parameter
approximation to the classical FP action which is valid for short correlation
lengths. We perform a scaling test of the action by computing the quantity where the string tension is measured from the
torelon mass . We measure on lattices of fixed physical
volume and varying lattice spacing (which we define through the
deconfinement temperature). While the Wilson action shows scaling violations of
about ten per cent, the approximate fixed point action scales within the
statistical errors for . Similar behaviour is found for
the potential measured in a fixed physical volume.Comment: 28 pages (latex) + 11 figures (Postscript), uuencode
Towards a perfect fixed point action for SU(3) gauge theory
We present an overview of the construction and testing of actions for SU(3)
gauge theory which are approximate fixed points of renormalization group
equations (at ). Such actions are candidates for use
in numerical simulations on coarse lattices.Comment: 6 pages, uuencoded compressed postscript file, contribution to LAT9
Dynamical Simulations with Smeared Link Staggered Fermions
One of the most serious problems of the staggered fermion lattice action is
flavor symmetry violation. Smeared link staggered fermions can improve flavor
symmetry by an order of magnitude relative to the standard thin link action.
Over the last few years different smearing transformations have been proposed,
both with perturbatively and non-perturbatively determined coefficients. What
hindered the acceptance and more general use of smeared link fermions until now
is the relative difficulty of dynamical simulations and the lack of
perturbative calculations with these actions. In both areas there have been
significant improvement lately, that I will review in this paper.Comment: 9 pages,5 figures; Plenary talk contribution to Lattice'200
Fixed point action and topological charge for SU(2) gauge theory
We present a theoretically consistent definition of the topological charge
operator based on renormalization group arguments. Results of the
measurement of the topological susceptibility at zero and finite temperature
for SU(2) gauge theory are presented.Comment: 3 pages, LaTeX file. Talk presented at LATTICE96(improvement
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