Singular defects with fractional topological charge in σ models and gauge theories . 1

Singular defects with fractional topological charge in σ models and gauge theories. Abstract A novel class of self-dual solutions in σ models and gauge theories is considered. The contribution of the corresponding fluctuations to the chiral condensate is calculated. We discuss the few tightly connected problems, such as the U (1) problem, the θ dependence and the chiral symmetry breaking within a framework of this approach. Arguments in favour of significance of the configurations with fractional topological charge are given.