The computational effort in the calculation of Wilson fermion quark propagators in Lattice Quantum Chromodynamics can be considerably reduced by exploiting the Wilson fermion matrix structure in inversion algorithms based on the non-symmetric Lanczos process. We consider two such methods: QMR (quasi minimal residual) and BCG (biconju-gate gradients). Based… (More)
We illustrate the current status of heavy quark physics on the lattice. Special emphasis is paid to the question of systematic uncertainties and to the connection of lattice computations to continuum physics. Latest results are presented and discussed with respect to the progress in methods, statistical accuracy and reliability.
We present results for spectroscopy, quark masses and decay constants obtained from SESAM's and TχL's large statistics simulations of QCD with two dynamical Wilson fermions.
We present the final analysis of the light and strange hadron spectra from a full QCD lattice simulation with two degenerate dynamical sea quark flavours at β = 5.6 on a 16 3 × 32 lattice. Four sets of sea quark masses corresponding to the range .69 ≤ m π /m ρ ≤ .83 are investigated. For reference we also ran a quenched simulation at β eff = 6.0, which is… (More)
Results from two studies of full QCD with two flavours of dynamical Wilson fermions are presented. At β = 5.6, the region 0.83 > mπ mρ > 0.56 at mπa > (0.23L) −1 is explored. The SESAM collaboration has generated ensembles of about 200 statistically independent configurations on a 16 3 × 32-lattice at three different κ-values and is entering the final phase… (More)
Flavor singlet combinations of quark operators O Γ S = ¯ uΓu + ¯ dΓd + ¯ sΓs contribute to many important physical observables in the low energy region of QCD. Experimentally one finds the values of some of these observables to be in sharp contrast to the naive (perturbative) theoretical expectations. This indicates that non perturbative vacuum properties… (More)
In order to compute physical quantities in lattice quantum chromodynamics huge systems of linear equations have to be solved. The availability of eecient parallel Krylov subspace solvers plays a vital role in the solution of these systems. We present a detailed analysis of the performance of the stabilized biconjugate gradient (BiCGStab) algorithm with… (More)
The calculation of physical quantities by lattice QCD simulations requires in some important cases the determination of the inverse of a very large matrix. In this article we describe how stochastic estimator methods can be applied to this problem, and how such techniques can be efficiently implemented on parallel computers.
Disconnected diagrams are expected to be sensitive to the inclusion of dynamical fermions. We present a feasibility study for the observation of such effects on the nucleonic matrix elements of the axial vector current, using SESAM full QCD vacuum configurations with Wilson fermions on 16 3 × 32 lattices, at β = 5.6. Starting from the standard methods… (More)
Full QCD with dynamical Wilson fermions on a 24 3 × 40-lattice – a feasibility study The investigation of light sea-quark effects in lattice QCD with dynamical Wilson fermions requires both larger physical volumes and finer lattice resolutions than achieved previously. As high-end supercomputers like the 512-node APE Tower provide the compute power to… (More)