Eigenmodes of the Dirac operator and chiral properties of QCD with sea quarks

I describe a mechanism to understand the relation between chiral-symmetry b reaking and eigenmodes of the Dirac operator in lattice QCD with Kogut-Suss kind sea quarks. It can be shown that if chiral symmetry is spontaneously b roken, the eigenvalues lambda, should behave as z(i)/V for large volume V, where z(i) is the i-th zero of the Bessel function. With neither chiral nor lambda extrapolation, one can precisely calculate the chiral condensate us ing only a small set of eigenvalues. Therefore, it is economical and free o f systematic uncertainties. I present the first QCD data to support this me chanism and encourage the lattice community to test and use it.