This book comprises the lectures of a two-semester course on quantum
field theory, presented in a quite informal and personal manner. The
course starts with relativistic one-particle systems, and develops the
basics of quantum field theory with an analysis on the representations
of the Poincaré group. Canonical quantization is carried out for scalar,
fermion, Abelian and non-Abelian gauge theories. Covariant quantization
of gauge theories is also carried out with a detailed description of the
BRST symmetry. The Higgs phenomenon and the standard model of
electroweak interactions are also developed systematically.
Regularization and (BPHZ) renormalization of field theories as well as
gauge theories are discussed in detail, leading to a derivation of the
renormalization group equation. In addition, two chapters -- one on the
Dirac quantization of constrained systems and another on discrete
symmetries -- are included for completeness, although these are not
covered in the two-semester course.This second edition includes two new
chapters, one on Nielsen identities and the other on basics of global
supersymmetry. It also includes two appendices, one on fermions in
arbitrary dimensions and the other on gauge invariant potentials and the
Fock-Schwinger gauge.
