Large $\theta$ angle in two-dimensional large $N$ ${\mathbb{CP}}^{N-1}$ model

Tsubasa Sugeno, Takahiro Yokokura, Kazuya Yonekura

In confining large $N$ theories with a $\theta$ angle such as four-dimensional $\mathrm{SU}(N)$ pure Yang-Mills theory, there are multiple metastable vacua and it makes sense to conside…