Towards Infrared Finite S-matrix in Quantum Field Theory

by Hayato Hirai

Overview

This book presents the better understanding of infrared structures of particle scattering processes in quantum electrodynamics (QED) in four-dimensional spacetime. An S-matrix is the fundamental quantity in scattering theory. However, if a theory involves massless particles, such as QED and gravity, the conventional S-matrix has not been well defined due to the infrared divergence, and infrared dynamics thus needs to be understood in-depth to figure out the S-matrix.

The book begins with introducing fundamental nature of the charge conservation law associated with asymptotic symmetry, and explaining its relations to soft theorems and memory effect. Subsequently it looks into an appropriate asymptotic state of the S-matrix without infrared divergences. The Faddeev-Kulish dressed state is known as a candidate of such a state, and its gauge invariant condition and its relation to the asymptotic symmetry are discussed. It offers an important building blocks for constructing the S-matrix without infrared divergences.

Product Details

ISBN-13:	9789811630477
Publisher:	Springer Nature Singapore
Publication date:	07/18/2021
Series:	Springer Theses
Edition description:	1st ed. 2021
Pages:	127
Product dimensions:	6.10(w) x 9.25(h) x (d)

Table of Contents

Introduction and Summary.- Asymptotic Symmetry.- Infrared Divergences.- Equivalence Between Soft Theorem and Asymptotic Symmetry.- Towards the IR nite S-matrix.- Conclusion and Further Discussion.- Appendix.