Speeding up finite step-size updating of full QCD on the lattice - art. no. 054505

We propose various improvements of finite step-size updating for full QCD o n the lattice that might turn finite step-size updating into a viable alter native to the hybrid Monte Carlo algorithm. These improvements are noise re duction of the noisy estimator of the fermion determinant, unbiased inclusi on of the hopping parameter expansion and a multi-level Metropolis scheme. First numerical tests are performed for the 2 dimensional Schwinger model w ith two flavors of Wilson fermions and for QCD with two flavors of Wilson f ermions and Schrodinger functional boundary conditions. [S0556-2821(99)0410 5-3].