Symmetries and symmetry breaking patterns in QCD: chiral and deconfinement transitions

The symmetry breaking pattern of QCD features two seemingly disconnected phenomena: the spontaneous breakdown of the image center symmetry in the deconfinement transition of pure-gauge QCD, and the spontaneous breaking of chiral image symmetry in the limit of image massless quark flavours. The dynamical entanglement of these symmetries is displayed in the framework of a schematic model (the PNJL model) in comparison with results from Lattice QCD. Extensions to non-zero baryon chemical potential are discussed.