Controlling Residual Chiral Symmetry Breaking in Domain Wall Fermion Simulations

At stronger gauge-field couplings, the domain wall fermion (DWF) residual mass (mres), a measure of chiral symmetry breaking (χSB), grows rapidly as it is largely due to near zero fermion eigenmodes of log(T ), where T is the 4D transfer matrix along the fifth dimension. The number of these eigenmodes increase rapidly at strong coupling. To suppress such near-zero eigenmodes, we have added to the DWF path integral a multiplicative weighting factor consisting of a ratio of determinants of Wilson-Dirac fermions having a chirally twisted mass with a large negative real component and a small imaginary chiral component. Numerical results show that this weighting factor with an appropriate choice of twisted masses significantly suppresses mres while allowing adequate topological tunneling. This research utilized resources at the New York Center for Computational Sciences at Stony Brook University/Brookhaven National Laboratory which is supported by the U.S. Department, of Energy under Contract No. DE-AC02-98CH10886 and by the, State of New York.