Lattice-QCD based Schwinger-Dyson approach for Chiral Phase Transition

Dynamical chiral-symmetry breaking in QCD is studied with the Schwinger-Dyson (SD) formalism based on lattice QCD data, i.e., LQCD-based SD formalism. We extract the SD kernel function $K(p^2)$ in an Ansatz-independent manner from the lattice data of the quark propagator in the Landau gauge. As remarkable features, we find infrared vanishing and intermediate enhancement of the SD kernel function $K(p^2)$. We apply the LQCD-based SD equation to thermal QCD with the quark chemical potential $\mu_q$. We find chiral symmetry restoration at $T_c \simeq 100{\rm MeV}$ for $\mu_q=0$. The real part of the quark mass function decreases as $T$ and $\mu_q$. At finite density, there appears the imaginary part of the quark mass function, which would lead to the width broadening of hadrons.