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arXiv · 0807.0466

Quantum phase transitions and new scales in QCD-like theories

Mithat Unsal
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Abstract

It is commonly believed that in confining vector-like gauge theories the center and chiral symmetry realizations are parametrically entangled, and if phase transitions occur, they must take place around the strong scale $\Lambda^{-1}$ of the gauge theory. We demonstrate that (non-thermal) vector-like theories formulated on ${\mathbb R}^{3} \times S^1$ where $S^1$ is a spatial circle exhibit new dynamical scales and new phenomena. There are chiral phase transitions taking place at $\Lambda^{-1}/N_c$ in the absence of any change in center symmetry. $\Lambda^{-1}/N_c$, invisible in (planar) perturbation theory, is also the scale where abelian versus non-abelian confinement regimes meet. Large $N_c$ volume independence (a working Eguchi-Kawai reduction) provides new insights and independently confirms the existence of these scales. We show that certain phases and scales are outside the reach of holographic (supergravity) modeling of QCD.

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Mithat Unsal. 2008-07-03. Quantum phase transitions and new scales in QCD-like theories. https://doi.org/10.1103/physrevlett.102.182002

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