Asymptotic Dynamics in Quantum Field Theory - When does the coupling switch off?

TL;DR

This paper analyzes the asymptotic dynamics in quantum field theory, identifying limitations of existing methods in certain interactions and proposing a more general approach applicable to various theories.

Contribution

It introduces a generalized method for studying asymptotic dynamics, overcoming issues in applying Kulish and Faddeev's approach to four-point interaction theories.

Findings

The original method faces problems with four-point interactions.

A new, more general approach is successfully applied to multiple theories.

Some theories exhibit coupling switching off at large times, others do not.

Abstract

We discuss the approach to asymptotic dynamics due to Kulish and Faddeev. We show that there are problems in applying this method to theories with four point interactions. The source of the difficulties is identified and a more general method is constructed. This is then applied to various theories including some where the coupling does switch off at large times and some where it does not.