QCD Thermodynamics: Lattice Results confront Models

Abstract

We show that lattice results on four flavor QCD at nonzero temperature and baryon density compare well with the hadron resonance gas model up to T approx. 0.95 Tc, and approach a free field behaviour with a reduced effective number of flavor for T \ge 1.5 Tc. Chiral symmetry and confinement are interrelated, and we note analogies between the critical line of QCD and that of simple models with the same global symmetries.

Comments: 5 pages, 4 figures; talk given at the conference Strong and Electroweak Matter 2004, Helsinki, Finland, 16-19 June 2004