Understanding QCD Phase Transition

This lecture delves into the physics of the de-confinement phase transition in QCD, exploring the crossover phenomenon and the approximate order parameter. The instructor discusses the accidental symmetry in QCD, the breaking of the SU3 left times SU3 right flavor symmetry, and the remnant of the chiral phase. The lecture also covers the lattice results showing the crossover at around 160 MeV, the confined phase with hadrons, and the quark-gluon plasma. The instructor explains the determination of the crossover as a second order transition and the scaling behavior near the critical point. The discussion extends to the O4 model, the emergence of pion waves, and the extraction of universal dynamical ratios.