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Phase Transitions at More Unusual Values of Theta

Sep 2026 · 0 citations · 42 references
Physics

Abstract

We calculate the $\theta$ dependence of the vacuum energy in an infinite family of cousins of QCD, where the vacuum structure can be analyzed exactly. These theories are $\mathcal{N}=1$ EFTs that descend from $\mathcal{N}=2$ $SU(N_c)$ gauge theory with $N_f$ flavors of fundamental hypermultiplets, that are then deformed by anomaly mediated supersymmetry breaking (AMSB). We reproduce results found in previous work that used the full $\mathcal{N}=2$ machinery but via a much simpler $\mathcal{N}=1$ method. Our method easily extends to infinitely many more theories for which the full $\mathcal{N}=2$ approach becomes intractable. We identify values of $\theta$ for which the theory undergoes a phase transition, and find that they can occur at both fractional and irrational values of $\theta/\pi$.

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