Mean Field, Instantons and Finite Baryon Density
  Instantons create a non-local interaction between the quarks, which at finite baryon density leads to the formation of a scalar diquark condensate and color superconductivity. A mean field approach leads to a self-consistent description of the $<\bar q q>$ and $<q q>$ condensates and shows the inevitability of a BCS type instability at the Fermi surface. The role of the rearrangement of the instanton ensemble for the QCD phase transitions is also discussed. 
Momchil Velkovsky