Non-Abelian strings and axions

Abstract

We address two distinct but related issues: (i) the impact of (two-dimensional) axions in a two-dimensional theory known to model confinement, the $CP(N\ensuremath{-}1)$ model; (ii) bulk axions in four-dimensional Yang-Mills theory supporting non-Abelian strings. In the first case $n$, $\overline{n}$ kinks play the role of ``quarks.'' They are known to be confined. We show that introduction of axions leads to deconfinement (at very large distances). This is akin to the phenomenon of wall liberation in four-dimensional Yang-Mills theory. In the second case we demonstrate that the bulk axion does not liberate confined (anti)monopoles, in contradistinction with the two-dimensional model. A novel physical effect which we observe is the axion radiation caused by monopole-antimonopole pairs attached to the non-Abelian strings.