Paper detail

Controlling Residual Chiral Symmetry Breaking in Domain Wall Fermion Simulations

At stronger gauge-field couplings, the domain wall fermion (DWF) residual mass, a measure of chiral symmetry breaking, grows rapidly. This measure is largely due to near zero fermion eigenmodes of logarithm of the 4D transfer matrix along the fifth dimension, and these eigenmodes increase rapidly at strong coupling. To suppress these 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 the residual mass while allowing adequate topological tunneling.