Instantons and Fermions on the Lattice

摘要: I address the question of how much QCD in chiral limit is reproduced by instantons. After reconstructing instanton content smoothed Monte Carlo lattice configurations, compare hadron spectroscopy on this ensemble to original “physical” configurations using a chirally optimised clover fermion action. Instantons themselves are shown break symmetry but correlators backgrounds strongly influenced free quark propagation. This results unnaturally light hadrons and small splitting between vector pseudoscalar meson channels. Superimposing perturbative zero momentum gauge field fluctuations instantons eliminates quarks restores physical correlators. argue that torons present only finite volumes, probably needed compensate large size effects due lack confinement ensemble.