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Results on the computational efficiency of 2-flavor staggered Wilson fermions compared to usual Wilson fermions in a quenched lattice QCD simulation on $16^3times32$ lattice at $beta=6$ are reported. We compare the cost of inverting the Dirac matrix on a source by the conjugate gradient (CG) method for both of these fermion formulations, at the same pion masses, and without preconditioning. We find that the number of CG iterations required for convergence, averaged over the ensemble, is less by a factor of almost 2 for staggered Wilson fermions, with only a mild dependence on the pion mass. We also compute the condition number of the fermion matrix and find that it is less by a factor of 4 for staggered Wilson fermions. The cost per CG iteration, dominated by the cost of matrix-vector multiplication for the Dirac matrix, is known from previous work to be less by a factor 2-3 for staggered Wilson compared to usual Wilson fermions. Thus we conclude that staggered Wilson fermions are 4-6 times cheaper for inverting the Dirac matrix on a source in the quenched backgrounds of our study.
The variational method is used widely for determining eigenstates of the QCD hamiltonian for actions with a conventional transfer matrix, e.g., actions with improved Wilson fermions. An alternative lattice fermion formalism, staggered fermions, does
We briefly describe some of our recent results for the mass spectrum and matrix elements using $O(a)$ improved fermions for quenched QCD. Where possible a comparison is made between improved and Wilson fermions.
QCD is investigated at finite temperature using Wilson fermions in the fixed scale approach. A 2+1 flavor stout and clover improved action is used at four lattice spacings allowing for control over discretization errors. The light quark masses in thi
We investigate the Kondo effect with Wilson fermions. This is based on a mean-field approach for the chiral Gross-Neveu model including four-point interactions between a light Wilson fermion and a heavy fermion. For massless Wilson fermions, we demon
We present some early results from a high statistics study of the scalar and pseudoscalar singlet sectors of lattice QCD using 2+1 flavours of Asqtad improved staggered fermions. The use of the Asqtad action has allowed us to generate an unprecedente