Introduction To Effective Field Theory

This advanced, accessible textbook on effective field theories uses worked examples to bring this important topic to a wider audience.

Using examples from across the sub-disciplines of physics, this introduction shows why effective field theories are the language in which physical laws are written. The tools of effective field theory are demonstrated using worked examples from areas including particle, nuclear, atomic, condensed matter and gravitational physics. To bring the subject within reach of scientists with a wide variety of backgrounds and interests, there are clear physical explanations, rigorous derivations, and extensive appendices on background material, such as quantum field theory. Starting from undergraduate-level quantum mechanics, the book gets to state-of-the-art calculations using both relativistic and nonrelativistic few-body and many-body examples, and numerous end-of-chapter problems derive classic results not covered in the main text. Graduate students and researchers in particle physics, condensed matter physics, nuclear physics, string theory, and mathematical physics more generally, will find this book ideal for both self-study and for organized courses on effective field theory.

This primer begins with a brief introduction to the main ideas underlying Effective Field Theory (EFT) and describes how nuclear forces are obtained from first principles by introducing a Euclidean space-time lattice for chiral EFT. It subsequently develops the related technical aspects by addressing the two-nucleon problem on the lattice and clarifying how it fixes the numerical values of the low-energy constants of chiral EFT. In turn, the spherical wall method is introduced and used to show how improved lattice actions render higher-order corrections perturbative. The book also presents Monte Carlo algorithms used in actual calculations. In the last part of the book, the Euclidean time projection method is introduced and used to compute the ground-state properties of nuclei up to the mid-mass region. In this context, the construction of appropriate trial wave functions for the Euclidean time projection is discussed, as well as methods for determining the energies of the low-lying excitations and their spatial structure. In addition, the so-called adiabatic Hamiltonian, which allows nuclear reactions to be precisely calculated, is introduced using the example of alpha-alpha scattering. In closing, the book demonstrates how Nuclear Lattice EFT can be extended to studies of unphysical values of the fundamental parameters, using the triple-alpha process as a concrete example with implications for the anthropic view of the Universe. Nuclear Lattice Effective Field Theory offers a concise, self-contained, and introductory text suitable for self-study use by graduate students and newcomers to the field of modern computational techniques for atomic nuclei and nuclear reactions.

Quantum field theory has had a profound influence on mathematics, and on geometry in particular. However, the notorious difficulties of renormalization have made quantum field theory very inaccessible for mathematicians. This provides complete mathematical foundations for the theory of perturbative quantum field theory, based on Wilson's ideas of low-energy effective field theory and on the Batalin-Vilkovisky formalism.

This book is a broad-based text intended to help the growing student body interested in constructing and applying methods of effective field theory to solve problems in their research. It begins with a review of using symmetries to identify the relevant degrees of freedom in a problem, and then presents a variety of methods that can be used to construct various effective theories. A detailed discussion of canonical applications of effective field theory techniques with increasing complexity is given, including Fermi's weak interaction, heavy-quark effective theory, and soft-collinear effective theory. Applications of these techniques to study physics beyond the standard model, dark matter, and quantum and classical gravity are explored. Although most examples come from questions in high-energy physics, many of the methods can also be applied in condensed-matter settings. Appendices include various factoids from group theory and other topics that are used throughout the text, in an attempt to make the book self-contained.

A modern introduction to quantum field theory for graduates, providing intuitive, physical explanations supported by real-world applications and homework problems.

The book constitutes a compact review of the applications of effective field theory methods in flavour physics, with emphasis on heavy quark physics. Some of the relevant applications are discussed to illustrate the method. It covers the full range of theoretical tools related to the application of the effective field theory idea: Starting from the weak interactions as an effective theory derived from the standard model, well-established methods such as heavy quark effective theory, the heavy quark mass expansion and chiral perturbation theory are addressed. Also more recent ideas such as QCD factorization and soft collinear effective theory are outlined. Finally the standard model itself is viewed as an effective theory, allowing a model-independent look at the results of the new physics. The book should be useful for the advanced graduate student as well as for scientists who are interested in the theoretical toolkit used in the context of flavour physics. It is not meant as a complete review of the subject, rather it should be useful as an introduction to the basic ideas.