Applications of quantum field theoretical methods to gravitational
physics, both in the semiclassical and the full quantum frameworks,
require a careful formulation of the fundamental basis of quantum
theory, with special attention to such important issues as
renormalization, quantum theory of gauge theories, and especially
effective action formalism. The first part of this graduate textbook
provides both a conceptual and technical introduction to the theory of
quantum fields. The presentation is consistent, starting from elements
of group theory, classical fields, and moving on to the effective action
formalism in general gauge theories. Compared to other existing books,
the general formalism of renormalization in described in more detail,
and special attention paid to gauge theories. This part can serve as a
textbook for a one-semester introductory course in quantum field theory.
In the second part, we discuss basic aspects of quantum field theory in
curved space, and perturbative quantum gravity. More than half of Part
II is written with a full exposition of details, and includes elaborated
examples of simplest calculations. All chapters include exercises
ranging from very simple ones to those requiring small original
investigations. The selection of material of the second part is done
using the "must-know" principle. This means we included detailed
expositions of relatively simple techniques and calculations, expecting
that the interested reader will be able to learn more advanced issues
independently after working through the basic material, and completing
the exercises.
