Gravitons and Pions

TL;DR

This paper reviews how effective field theory provides a useful framework for understanding low-energy behaviors of gravitons and pions, emphasizing the simplicity of the gravitational case due to masslessness and scale separation.

Contribution

It offers an overview of effective field theory applications to gravitons and pions, highlighting the advantages in the gravitational context.

Findings

Effective field theory describes low-energy interactions of gravitons and pions.

The gravitational case is simplified by the masslessness of gravitons.

Scale separation makes the effective field theory approach particularly clean.

Abstract

Both gravitons and pions are described by non-linear and non-renormalizable actions at low energies. These are most usefully treated by effective field theory, which is a full quantum field theoretic approach that relies only on the low energy degrees of freedom and their interactions. The gravitational case is particularly clean because of the masslessness of the graviton and the wide separation of scales. This essay provides an overview of this approach.