Remarks on Higgs Inflation

TL;DR

This paper examines Higgs inflation models, highlighting issues with perturbative unitarity in simple models and proposing asymptotically safe gravity as a solution where the standard model Higgs can drive inflation without new physics.

Contribution

It analyzes unitarity bounds in Higgs inflation models and suggests asymptotically safe gravity enables Higgs-driven inflation within the standard model framework.

Findings

Simple Higgs inflation models face unitarity problems.

Asymptotically safe gravity allows Higgs inflation without new particles.

Standard model Higgs can potentially explain inflation and electroweak symmetry breaking.

Abstract

We discuss models where the Higgs boson of the electroweak standard model plays the role of the inflaton. We focus on the question of the violation of perturbative unitarity due to the coupling of the Higgs boson either to the Ricci scalar or to the Einstein tensor and discuss the background dependence of the unitarity bounds. Our conclusion is that the simplest model which restricts itself to the standard model Higgs boson without introducing further degrees of freedom has a serious problem. However, in the asymptotically safe gravity scenario, the Higgs boson of the standard model could be the inflaton and no physics beyond the standard model is required to explain both inflation and the spontaneous breaking of the electroweak symmetry of the standard model.