Instantons and the \theta vacuum in non-linear \sigma model and QCD

TL;DR

This paper discusses the role of instantons and the  vacuum in non-linear sigma models and QCD, exploring their implications for symmetry and cluster properties in quantum field theories.

Contribution

It provides an analysis of instantons and the  vacuum within non-linear sigma models and QCD, highlighting their effects on symmetry and vacuum structure.

Findings

Insights into the  vacuum structure in QCD and sigma models

Implications of instantons for symmetry breaking

Discussion on cluster properties in quantum field theories

Abstract

This is a talk given on the $\theta $vacuum and cluster properties and the non-linear sigma model proposed to be given on occasion of an invitation to the seventh international conference on Symmetry in Nonlinear Physics,June 24 - 30, 2007, Kiev.