Phase transitions in asymmetric nuclear matter

Abstract

We discuss the structure of the three-dimension pressure-temperature-asymmetry surface of equilibrium of the asymmetric nuclear matter, studied within the thermal Thomas-Fermi approximation, and present results for the caloric curves in the case of isobaric heating. We pay special attention to the difference of the asymmetry parameter between the boiling sheet and that of the condensation sheet of the surface of equilibrium and show that hot nuclear matter can exist (in a bound state) at higher asymmetry than the cold one. We demonstrate the presence of the plateau region in caloric curves at the isobaric heating of the asymmetric nuclear matter and show that the shape of the caloric curve depends on the pressure and is sensitive to the value of the asymmetry parameter. We also point out that the experimental value of the plateau temperature T≈5–7 MeV corresponds to the pressure P=10−2 MeV/fm3 at the isobaric boiling.