Introduction to Gauge Field Theory Revised Edition Graduate Student Series in Physics

This is a revised edition of the popular text for postgraduate students on Feynman's path integral treatment of gauge theories. There is a new section on instantons and axions, and calculations have been updated to make use of the more precise values of gauge coupling constants now available. The chapters are basically of the same structure but minor corrections have been made and new material added. Firstly the groundwork is laid with an introduction to classical field theory and the concept of the path integral in nonrelativistic quantum mechanics. The path integral formalism is then applied to the quantum field theory of a scalar field. Next the Feynman rules and the methods needed to calculate scattering amplitudes are developed, and the idea of renormalisation is introduced. The formalism is then extended to the quantum field theory of fermions which requires path integrals to be evaluated over Grassmann variables. The stage is now set for a discussion of gauge field theories in both the Abelian and non-Abelian cases. There is a detailed treatment of quantum electrodynamics and quantum chromodynamics with emphasis on asymptotic freedom in QCD and here several calculations have been reworked. The electroweak theory is treated after the concept of spontaneous symmetry breaking has been introduced. In this chapter new material on a classical gauge field configuration which is not a spontaneously broken gauge symmetry is given and instantons and axions are introduced. The possibility that one day a single theory might unify quantum chromodynamics and electroweak theory is discussed in a chapter on grand unified theories where again calculations have been updated. Finally, there is anintroduction to field theory at finite temperatures, which has applications in cosmology, especially in the first few moments of the universe after the big bang. Throughout the text there are problems to assist readers in developing their understanding of the subject and problems