Abstract
The overlap fermion propagator is calculated on 2 + 1 flavor domain-wall fermion gauge configurations on 16(3) x 32, 24(3) x 64 and 32(3) x 64 lattices. With hyper-cubic (HYP) smearing and low eigenmode deflation, it is shown that the inversion of the overlap operator can be expedited by similar to 20 times for the 16(3) x 32 lattice and similar to 80 times for the 32(3) x 64 lattice. The ...
Abstract
The overlap fermion propagator is calculated on 2 + 1 flavor domain-wall fermion gauge configurations on 16(3) x 32, 24(3) x 64 and 32(3) x 64 lattices. With hyper-cubic (HYP) smearing and low eigenmode deflation, it is shown that the inversion of the overlap operator can be expedited by similar to 20 times for the 16(3) x 32 lattice and similar to 80 times for the 32(3) x 64 lattice. The overhead cost for calculating eigenmodes ranges from 4.5 to 7.9 propagators for the above lattices. Through the study of hyperfine splitting, we found that the O(m(2)a(2)) error is small and these dynamical fermion lattices can adequately accommodate quark mass up to the charm quark. A preliminary calculation of the low-energy constant Delta(mix) which characterizes the discretization error of the pion made up of a pair of sea and valence quarks in this mixed-action approach is carried out via the scalar correlator with periodic and antiperiodic boundary conditions. It is found to be small which shifts a 300 MeV pion mass by similar to 10 to 19 MeVon these sets of lattices. We have studied the signal-to-noise issue of the noise source for the meson and baryon. We introduce a new algorithm with Z(3) grid source and low eigenmode substitution to study the many-to-all meson and baryon correlators. It is found to be efficient in reducing errors for the correlators of both mesons and baryons. With 64-point Z(3) grid source and low-mode substitution, it can reduce the statistical errors of the light quark (m(pi) similar to 200-300 MeV) meson and nucleon correlators by a factor of similar to 3-4 as compared to the point source. The Z(3) grid source itself can reduce the errors of the charmonium correlators by a factor of similar to 3.
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