Renormalization group flow equation at finite density - art. no. 035202

For the linear sigma model with quarks we derive renormalization group flow equations for finite temperature and finite baryon density using the heat kernel cutoff. At zero temperature we evolve the effective potential to the Fermi momentum and compare the solutions of the full evolution equation wi th those in the mean field approximation. We find a first order phase trans ition either from, a massive constituent quark phase to a mixed phase, wher e both massive and massless quarks are present, or from a metastable consti tuent quark phase at low density to a stable massless quark phase at high d ensity. In the latter solution, the formation of droplets of massless quark s is realized even at low density.