Dynamical Domain Wall Fermions

In the quenched approximation Domain Wall Fermions [1,2] (DWF) have been found to be an extremely successful approach to simulating QCD on the lattice. Crucial to this success is the fact that, when working at weak couplings (a ≈ 2GeV) and using improved gauge actions such as the DBW2 action, the degree of explicit chiral symmetry breaking is very small for practically useful sizes of the fifth dimension (O(10)). Early simulations of dynamical DWF, performed at relatively coarse couplings, suggested that Ls ≈ O(100) would be needed before the degree of chiral symmetry breaking was small enough to be acceptable. Here we will report on the progress of a preliminary study [3] of Nf = 2 dynamical DWF in which we both adopt the DBW2 gauge action, and move to weaker coupling, in an attempt to find a region of parameter space where dynamical DWF simulations are practical.