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Overlap Quark Propagator in Coulomb Gauge QCD and the Interrelation of Confinement and Chiral Symmetry Breaking

The chirally symmetric overlap quark propagator is explored in Coulomb gauge for the first time. This gauge is especially well suited for studying the interrelation between confinement and chiral symmetry breaking, since confinement can be attributed to the infrared divergence of the vector dressing function of the inverse quark propagator. Using quenched gauge field configurations on a $20^4$ lattice, the dressing functions of the quark propagator as well as the dynamical quark mass function are evaluated, also in the chiral limit. Chiral symmetry is artificially restored by removing the low mode contribution from the quark propagator. After removing enough low-lying modes, the dynamical quark mass function approaches the current quark mass in the whole momentum region and goes to zero in the chiral limit. However, the vector dressing function is unaffected by the low-mode removal. It follows that the quark energy dispersion is still infrared divergent and quarks in such a chiral symmetry restored phase are still confined within a hadron.