Matthias Hempel, Veronica Dexheimer, Stefan Schramm, Igor Iosilevskiy
We investigate non-congruent first-order phase transitions (PTs) relevant for heavy-ion collisions and neutron stars in Coulomb-less models. Two different phase transitions are considered: the nuclear liquid-gas PT at sub-saturation densities and the deconfinement PT at high densities and/or temperatures. For the first PT, we use the FSUgold relativistic mean-field model and for the second one the relativistic chiral SU(3) model. The chiral SU(3) model is one of the few models for the deconfinement phase transition, which contains quarks and hadrons in arbitrary proportions (i.e. a "solution") and gives a continuous transition from pure hadronic to pure quark matter above a critical point. The study shows the universality of the applied concept of non-congruence for the two phase transitions with an upper critical point, and illustrates the different typical scales involved. In addition, we find a principle difference between the liquid-gas and the deconfinement PTs: in contrast to the ordinary Van-der-Waals-like PT, the phase coexistence line of the deconfinement PT has a negative slope in the pressure-temperature plane. Furthermore, we also find that the non-congruent features of the deconfinement PT become vanishingly small around the critical point.
View original:
http://arxiv.org/abs/1302.2835
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