Domain Walls, Z(n) Charge and a 0 Condensate: a Canonical Ensemble Study

The deconfinement phase transition is studied in the ensemble canonical with respect to triality. Since this ensemble implies a projection to the zero triality sector of the theory we introduce a quantity which is insensitive to Z(N c) symmetry but can reveal a critical behaviour in the theory with dy-namical quarks. Further, we argue that in the canonical ensemble description of full QCD there exist domains of different Z(N c) phases which are degenerate and possess normal physical properties. This contradicts the predictions of the grand canonical ensemble. We propose a new order parameter to test the realization of the discrete Z(N c) symmetry at finite temperature and calculate it for the case of Z(2) gauge fields coupled to fundamental fermions.