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arXiv · hep-th/0305065

Theta-vacuum: Phase Transitions and/or Symmetry Breaking at $θ= π$

V. Azcoiti·A. Galante·V. Laliena
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Abstract

Assuming that a quantum field theory with a $θ$-vacuum term in the action shows non-trivial $θ$-dependence and provided that some reasonable properties of the probability distribution function of the order parameter hold, we argue that the theory either breaks spontaneously CP at $θ= π$ or shows a singular behavior at some critical $θ_c$ between 0 and $π$. This result, which applies to any model with a pure imaginary contribution to the euclidean action consisting in a quantized charge coupled to a phase, as QCD, is illustrated with two simple examples; one of them intimately related to Witten's result on SU(N) in the large $N$ limit.

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V. Azcoiti, A. Galante, V. Laliena. 2003-05-21. Theta-vacuum: Phase Transitions and/or Symmetry Breaking at $θ= π$. https://doi.org/10.1143/ptp.109.843

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