We describe and test a method to compute Euclidean meson two-point functions in lattice QCD. The contribution from the low-lying eigenmodes of the Dirac operator is averaged over all positions of the quark sources. The contribution from the higher modes is estimated in the traditional way with one or a few source points per lattice. In some channels, we observe a significant improvement in the two-point functions for small quark masses.
@article{arxiv.hep-lat/0401011,
title = {Improving meson two-point functions in lattice QCD},
author = {Thomas DeGrand and Stefan Schaefer},
journal= {arXiv preprint arXiv:hep-lat/0401011},
year = {2009}
}