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Following Symanzik we argue that the Schrödinger functional in lattice gauge theories without matter fields has a well-defined continuum limit. Due to gauge invariance no extra counter terms are required. The Schrödinger functional is, moreover, accessible to numerical simulations. It may hence be used to study the scaling properties of the theory and in(More)
We explain in detail how to estimate mean values and assess statistical errors for arbitrary functions of elementary observables in Monte Carlo simulations. The method is to estimate and sum the relevant autocorrelation functions, which is argued to produce more certain error estimates than binning techniques and hence to help toward a better exploitation(More)
The running of renormalized quark masses is computed in lattice QCD with two massless O(a) improved Wilson quarks. The regularization and flavor independent factor that relates running quark masses to the renormalization group invariant ones is evaluated in the Schrödinger Functional scheme. Using existing data for the scale r0 and the pseudoscalar meson(More)
We present a new normalization condition for the axial current, derived from the PCAC relation with non–vanishing quark mass. This condition is expected to reduce mass effects in the chiral extrapolation of the results for the normalization factor ZA. The application to the two–flavor theory with improved Wilson fermions shows that this expectation is(More)
Large cutoff effects of dynamical Wilson fermions ∗ R. Sommer, S. Aoki, M. Della Morte, R. Hoffmann, T. Kaneko, F. Knechtli, J. Rolf, I. Wetzorke and U. Wolff (ALPHA, CP-PACS and JLQCD Collaborations) DESY Zeuthen, Platanenallee 6, 15738 Zeuthen, Germany CERN–TH, CH–1211 Geneva 23, Switzerland Institute of Physics, University of Tsukuba, Tsukuba, Ibaraki(More)
In the simplified setting of the Schwinger model we present a systematic study on the simulation of dynamical fermions by global accept/reject steps that take into account the fermion determinant. A family of exact algorithms is developed, which combine stochastic estimates of the determinant ratio with the exploitation of some exact extremal eigenvalues of(More)
As a feasibility study for a scaling test we investigate the behavior of algorithms for dynamical fermions in the N f = 2 Schrödinger functional at an intermediate volume of 1 fm 4. Simulations were performed using HMC with two pseudo–fermions and PHMC at lattice spacings of approximately 0.1 and 0.07 fm. We show that some algorithmic problems are due to(More)
We study autocorrelation times of physical observables in lattice QCD as a function of the molecular dynamics trajectory length in the hybrid Monte-Carlo algorithm. In an interval of trajectory lengths where energy and reversibility violations can be kept under control, we find a variation of the integrated autocorrelation times by a factor of about two in(More)