Can Inflation be Connected to Low Energy Particle Physics?

TL;DR

This paper explores whether low energy particle physics, specifically the Higgs field, can be responsible for early universe inflation, highlighting the need for UV completion and the disconnect between inflationary potential and low energy physics.

Contribution

It introduces a simple Higgs-inflation model with minimal coupling, analyzes the role of heavy fields and Higgs self-coupling, and presents a new class of models including supergravity versions.

Findings

Small Higgs self coupling lambda is required for effective field theory.

UV completion influences the inflationary regime.

Inflationary potential may be disconnected from low energy physics.

Abstract

It is an interesting question whether low energy degrees of freedom may be responsible for early universe inflation. To examine this, here we present a simple version of Higgs-inflation with minimal coupling to gravity and a quadratic inflationary potential. This quantitatively differs from the popular non-minimally coupled models, although it is qualitatively similar. In all such models, new heavy fields must enter in order for the theory to be well behaved in the UV. We show that in all cases the Higgs self coupling lambda must be quite small in order to integrate out the heavy fields and use the resulting low energy effective field theory of the Higgs to describe inflation. For moderately sized lambda, the UV completion is required and will, in general, determine the inflationary regime. We discuss the important issue of the arbitrariness of the Lagrangians used in all these setups by presenting a new class of such models, including a supergravity version. This suggests that the inflationary potential is disconnected from low energy physics.