Finite-Size Effects in Lattice QCD with Dynamical Wilson Fermions
Orth
Boris
Orth, Boris
aut
2004-07-28
2004-10-13
2014-08-12
en
<p>
Due to limited computing resources choosing the parameters for a full
Lattice QCD simulation always amounts to a compromise between the
competing objectives of a lattice spacing as small, quarks as light,
and a volume as large as possible. Aiming at pushing unquenched
simulations with the Wilson action towards the computationally
expensive regime of small quark masses, the GRAL project addresses the
question whether computing time can be saved by sticking to lattices
with rather modest numbers of grid sites and extrapolating the
finite-volume results to the infinite volume (prior to the usual
chiral and continuum extrapolations). In this context we investigate
in this work finite-size effects in simulated light hadron
masses. Understanding their systematic volume dependence may not only
help saving computer time in light quark simulations with the Wilson
action, but also guide future simulations with dynamical chiral
fermions which for a foreseeable time will be restricted to rather
small lattices.
<p>
We analyze data from Hybrid Monte Carlo simulations with the standard
two-flavor Wilson action at two different values of the coupling
parameter, β = 5.6 (lattice spacing a ≈ 0.08fm) and
β = 5.32144 (a ≈ 0.13fm). The larger β corresponds to the
coupling used previously by SESAM/TχL. The considered hopping
parameters κ = 0.1575, 0.158 (at the larger β) and
κ = 0.1665 (at the smaller β) correspond to quark masses of
85, 50 and 36% of the strange quark mass. At each quark mass we study
at least three different lattice extents in the range from L=10 to
L = 24 (0.85-2.04fm). Estimates of autocorrelation times in the
stochastic updating process and of the computational cost of every run
are given. For each simulated sea quark mass we calculate quark
propagators and hadronic correlation functions in order to extract the
pion, rho and nucleon masses as well as the pion decay constant and
the quark mass from the PCAC relation. We examine to what extent the
volume dependence of the masses can be parameterized by simple
functions based on M. Lüscher's analytic formula and previous
numerical findings by other groups. The applicability of results for
the pion and the nucleon from Chiral Effective Theory in the parameter
regime covered by our simulations is discussed. Cut-off effects in the
PCAC quark mass are found to be under control.
urn:nbn:de:hbz:468-20040501
2014-08-12T08:36:02.653Z
2014-08-12T09:51:08.243Z
published
Diss
fbc/physik/diss2004/orth