Exploring chiral dynamics with overlap fermions

This talk presents a lattice study of spontaneous chiral symmetry breaking performed by the JLQCD and TWQCD collaborations with dynamical overlap fermions. Our lattice configurations are generated in a fixed topological sector. Since finite volume effects, partly due to the fixed global topology, are mainly induced by pion fields, the dependence on the lattice volume, topological charge and quark masses can be analytically predicted using chiral perturbation theory (ChPT). We find a good agreement of Dirac operator spectrum calculated on the lattice with the ChPT prediction including its finite size scalings, through which the chiral condensate is determined with good accuracy.