Determination of the chiral condensate from QCD Dirac spectrum on the lattice

H. Fukaya, S. Aoki, T. W. Chiu, S. Hashimoto, T. Kaneko, J. Noaki, T. Onogi, N. Yamada

Published 2010-12-18, updated 2011-03-01Version 3

We calculate the chiral condensate of QCD with 2, 2+1 and 3 flavors of sea quarks. Lattice QCD simulations are performed employing dynamical overlap fermions with up and down quark masses covering a range between 3 and 100 MeV. On L ~ 1.8-1.9 fm lattices at a lattice spacing ~ 0.11 fm, we calculate the eigenvalue spectrum of the overlap-Dirac operator. By matching the lattice data with the analytical prediction from chiral perturbation theory at the next-to-leading order, the chiral condensate in the massless limit of up and down quarks is determined.