The CP(N-1) model on a Disc and Decay of a Non-Abelian String

TL;DR

This paper investigates quantum effects on the decay of non-abelian strings in non-supersymmetric gauge theory by analyzing the $CP(N-1)$ model on a disc, revealing phase transitions and boundary effects.

Contribution

It calculates the effective action of the $CP(N-1)$ model on a disc at large N, uncovering phase transitions and boundary contributions relevant to non-abelian string decay.

Findings

Phase transition at a critical radius.

Presence of a 'wrong sign' Luscher term.

Large negative boundary contribution (boojum-like).

Abstract

We consider the role of quantum effects in the non-perturbative decay of non-abelian string with orientational moduli in non-supersymmetric D=4 gauge theory. To this aim the effective action in the $CP(N-1)$ model on a disc at large N has been calculated. It exhibits phase transition at some radius, the "wrong sign" Luscher term and large boundary boojum-like negative contribution. The effect of $\theta$ - term and the possibility of the spontaneous creation of the non-abelian string are briefly discussed.