From 4d Yang-Mills to 2d \u2102\u2119N\u2009\u2212\u20091 model: IR problem and confinement at weak coupling

Abstract

We study four-dimensional SU(N) Yang-Mills theory on mathbb{R}times {mathbb{T}}^3=mathbb{R}times {S}_A^1times {S}_B^1times {S}_C^1 , with a twisted boundary condition by a ℤN center symmetry imposed on SB1 × SC1. This setup has no IR zero modes and hence is free from IR divergences which could spoil trans-series expansion for physical observables. Moreover, we show that the center symmetry is preserved at weak coupling regime. This is shown by first reducing the theory on {mathbb{T}}^2={S}_Atimes {S}_B , to connect the model to the two-dimensional ℂℙN− 1-model. Then, we prove that the twisted boundary condition by the center symmetry for the Yang-Mills is reduced to the twisted boundary condition by the ℤN global symmetry of ℂℙN− 1. There are N classical vacua, and fractional instantons connecting those N vacua dynamically restore the center symmetry. We also point out the presence of singularities on the Borel plane which depend on the shape of the compactification manifold, and comment on its implications.