Ladder-QCD at finite isospin chemical potential

Abstract

We use an effective QCD model (ladder-QCD) to explore the phase diagram for chiral symmetry breaking and restoration at finite temperature with different $u,d$ quark chemical potentials. In agreement with a recent investigation based on the Nambu-Jona-Lasinio model, we find that a finite pion condensate shows up for high enough isospin chemical potential ${\mu }_I=({\mu }_u-{\mu }_d)/2$. For small ${\mu }_I$ the phase diagram in the $({\mu }_B,T)$ plane shows two first order transition lines and two critical ending points.

Comments: Typed in RevTex4, pages 12, figures 2. Two references added