Condition for gapless color-antitriplet excitations in NJL models
  We present an exact condition for the existence of gapless quasiparticle excitations in NJL models of color superconducting quark matter with a quark-quark interaction in the scalar color-antitriplet channel. The condition can be represented by a rotated ellipse in the plane of mass and chemical potential differences for the paired quark fields. 
F. Sandin, A.M. Oztas