Index Theorem for non-Supersymmetric Fermions Coupled to a non-Abelian String and Electric Charge Quantization

Abstract

Non-Abelian strings are considered in {\em non}-supersymmetric theories with fermions in various appropriate representations of the gauge group U($N$). We derive the electric charge quantization conditions and the index theorems counting fermion zero modes in the string background both for the left-handed and right-handed fermions. In both cases, we observe a non-trivial $N$ dependence.