The QCD equation of state and transition at finite temperature

Abstract

We present the latest results for the equation of state and the crossover transition in 2+1 flavor QCD fromthe HotQCD Collaboration. Bulk thermodynamic quantities-energy density, pressure, entropy density, and the speed of sound-are calculated on lattices with temporal extent Nt = 8 in the temperature range 140MeV> T > 540MeV. We utilize two improved staggered fermion actions, asqtad and p4, with the mass for the two degenerate light quarks chosen to be mud = 0.1ms, corresponding to m-220 MeV for the lightest pion. We also calculate observables that are sensitive to the chiral and deconfing transitions-the light and strange quark number susceptibilities, the chiral condensate, and the renormalized Polyakov loop-finding that deconfinement and chiral symmetry restoration occur in the same narrow temperature interval.