QCD PHASE-TRANSITIONS FROM RELATIVISTIC HADRON MODELS

The models of translationally invariant infinite nuclear matter in the relativistic mean field models are very interesting and simple, since the nucleon can connect only to a constant vector and scalar meson fi eld. Can one connect these to the complicated phase transitions of QCD ? For an affirmative answer to this question, one must consider models where the coupling constants to the scalar and vector fields depend o n density in a nonlinear way, since as such the models are not explici tly chirally invariant. Once this is ensured, indeed one can derive a quark condensate indirectly from the energy density of nuclear matter which goes to zero at large density and temperature. The change to zer o condensate indicates a smooth phase transition.