Two-Dimensional sigma Models: Modelling Non-Perturbative Effects of Quantum Chromodynamics

摘要

The basic features of the O(N) sigma models are discussed. Some aspects of the Wilson operator expansion (OPE) are considered: mathematical formulation of OPE, its physical meaning and non-perturbative vacuum expectations of local operators. It is concluded that OPE is well defined outside the perturbation theory. The anomaly in the trace of the energy-momentum tensor is studied. It is shown that the anomaly determines the masses of physical particles. Low-energy theorems which relate low-energy scattering amplitudes to non-perturbative vacuum expectation values of some operators are investigated. (Atomindex citation 16:083244)