Reducing Baryon Noise in Lattice QCD Through Partial Quenching

Abstract

The study of nuclear physics using lattice QCD is hindered by an exponentially large signal-to-noise problem which is conventionally alleviated by raising the quark masses to unphysically high values. We propose a novel form of partial quenching for calculations involving nucleons in which the sea quark masses are taken to be smaller than the valence quark masses. It is shown that lowering the sea quark masses toward their physical values actually improves signal-to-noise. An optimized approach to the physical point in the (m_s, m_v) plane is proposed, with a full analysis of the cost benefit. Improvements in computing time of ~ 10^(2(A-1)), where A is the number of nucleons in the system, are shown to be possible.