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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)

LPHA A Collaboration Abstract: 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 Z A. The application to the two–flavor theory with improved Wilson fermions… (More)

- Michele Della Morte, Roland Hoffmann, Rainer Sommer, Ines Wetzorke, Ulli Wolff
- 2005

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 renor-malization group invariant ones is evaluated in the Schrödinger Functional scheme. Using existing data for the scale r 0 and the pseudoscalar meson… (More)

- Peter Weisz, Ulli Wolff
- 2001

We compute the Schrödinger functional (SF) for the case of lattice QCD with Wilson fermions (with and without SW improvement) at two-loop order in lattice perturbation theory. This allows us to extract the three-loop β-function in the SF-scheme. These results are required to compute the running coupling, the Λ-parameter and quark masses by finite size… (More)

We present and discuss results for cutoff effects in the PCAC masses and the mass dependence of r0 for full QCD and various fermion actions. Our discussion of how one computes mass dependences – here of r0 – is also relevant for comparisons with chiral perturbation theory.

- Ulli Wolff
- 2003

LPHA A Collaboration Abstract 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… (More)

- Harvey Meyer, Hubert Simma, Rainer Sommer, Michele Della Morte, Oliver Witzel, Ulli Wolff
- Computer Physics Communications
- 2007

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)

- Michele Della Morte, Roland Hoffmann, Francesco Knechtli, Ulli Wolff
- Computer Physics Communications
- 2005

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)

- Shinji Takeda, Ulli Wolff
- 2007

We present a multiplication algorithm to recursively construct vertices for the Schrödinger functional in the abelian background field case. The algorithm is suited for automatic perturbative calculations with a variety of actions. As first applications, we derive ratios of the lambda parameters between the lattice scheme (improved gauge actions including… (More)

- Ulli Wolff
- 2008

We investigate in some detail an alternative simulation strategy for lattice field theory based on the so-called worm algorithm introduced by Prokof'ev and Svistunov in 2001. It amounts to stochastically simulating the strong coupling expansion rather than the usual configuration sum. A detailed error analysis and an important generalization of the method… (More)