Quantum Phase Transitions and New Scales in QCD-like Theories

Abstract

It is commonly believed that in confining vectorlike gauge theories the center and chiral symmetry transition scales are parametrically of the same order and take place around the strong scale Lambda -1. We demonstrate that (nonthermal) compactification of such theories on R 3 x S1 exhibit new phase transition scales and unexpected phenomena. There are cases with single chiral symmetry breaking at an exotic scale Lambda-1/Nc in the absence of any change in center symmetry. The scale Lambda -1/N c,invisible in perturbation theory, is also the scale where Abelian versus non-Abelian confinement regimes meet. Large N c volume independence provides new insights and independently confirms the existence of these scales. We also show that certain phases and scales are outside the reach of holographic (supergravity) modeling of QCD.