Year: 2025
Type: article
Abstract: A bstract In confining large N theories with a θ angle such as four-dimensional SU( N ) pure Yang-Mills theory, there are multiple metastable vacua and it makes sense to consider the parameter region of “large θ of order N ” despite the fact that θ is a 2 π -periodic parameter. We investigate this parameter region in the two-dimensional $$ {\mathbbm{CP}}^{N-1} $$ CP N − 1 model by computing the partition function on T 2 . When θ / N is of order $$ \mathcal{O}(0.1) $$ O 0.1 or less, we get perfectly sensible results for the vacuum energies and decay rates of metastable vacua. However, when θ / N is of order $$ \mathcal{O}(1) $$ O 1 , we encounter a problem about saddle points that would give larger contributions to the partition function than the true vacuum. We discuss why it might not be straightforward to resolve this problem.
Source: Journal of High Energy Physics
Institution: Tohoku University
Language: English
Subfield: Nuclear and High Energy Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: diamond
OpenAlex ID: W4410808916