Effect of Light Fermions on the Confinement Transition in QCD-Like Theories

Abstract

The dependence of the confinement transition parameters on the fermion content provides information on the mechanism of confinement. Recent progress in lattice gauge theories has allowed us to study it for a light flavor number Nf∼O(10) and found this transition to shift toward significantly stronger coupling. We propose an explanation for that: light fermions can occupy the chromomagnetic monopoles, via zero modes, making them "distinguishable" and unsuitable for Bose-Einstein condensation. Such dilution of unoccupied monopoles is compensated by stronger coupling that makes them lighter and more numerous. We also suggest that flavor-carrying quark-monopole objects account for the density beyond the quark Fermi sphere seen in the cold dense phase of Nc=2 lattice QCD.