Chiral Crossover and Chiral Phase Transition Temperatures from Lattice QCD

We review our recent studies on chiral crossover and chiral phase transition temperatures in this special issue. We will firstly present a lattice QCD based determination of the chiral crossover transition temperature at zero and nonzero baryon chemical potential \mu_\rmB which is T_\rmpc\!=\!(156.5\pm1.5) MeV. At nonzero temperature the curvatures of the chiral crossover transition line are \kappa^\rmB_2=0.012(4) and \kappa^\rmB_4=0.000(4) for the 2nd and 4th order of \mu_\rmB/T. We will then present a first determination of chiral phase transition temperature in QCD with two degenerate, massless quarks and a physical strange quark. After thermodynamic, continuum and chiral extrapolations we find the chiral phase transition temperature T_\rmc^0\!=\!132^+3_-6 MeV.