We reexamine the recent instanton motivated studies of Alford, Rajagopal, and Wilczek, and Berges and Rajagopal in the framework of the standard SU(2) Nambu–Jona-Lasinio (NJL) model. The chiral phase diagram is calculated in the temperature-density plane, and the pressure is evaluated as the function of the quark density. Obtaining simple approximate relations describing the T-μ and $T-p_F$ phase transition lines, we find that the results of the instanton based model and that of the NJL model are identical. The diquark transition line is also given.

• Received 11 June 1999

DOI:https://doi.org/10.1103/PhysRevC.60.055205