Thermodynamic instabilities in dynamical quark models with complex   conjugate mass poles
  We show that the CJT thermodynamic potential of dynamical quark models with a quark propagator represented by complex conjugate mass poles inevitably exhibits thermodynamic instabilities. We find that the minimal coupling of the quark sector to a Polyakov loop potential can strongly suppress but not completely remove such instabilities. This general effect is explicitly demonstrated in the framework of a covariant, chirally symmetric, effective quark model. 
Sanjin Beni\'c, David Blaschke, Michael Buballa
hep-ph nucl-th