# Dynamics of Relaxed Inflation

## TL;DR

This paper explores a novel inflationary model where the relaxion field acts as the inflaton, coupling to gauge bosons to enable a unique reheating process via Schwinger pair production, addressing the hierarchy problem.

## Contribution

It introduces a new cosmological relaxation model with the relaxion as inflaton, coupling to gauge fields, and a novel Schwinger reheating mechanism, extending previous relaxation theories.

## Key findings

- Achieves a cutoff near the Planck scale.
- Identifies the need for additional fields to generate sufficient curvature perturbations.
- Proposes a gauge-boson driven reheating process via Schwinger effect.

## Abstract

The cosmological relaxation of the electroweak scale has been proposed as a mechanism to address the hierarchy problem of the Standard Model. A field, the relaxion, rolls down its potential and, in doing so, scans the squared mass parameter of the Higgs, relaxing it to a parametrically small value. In this work, we promote the relaxion to an inflaton. We couple it to Abelian gauge bosons, thereby introducing the necessary dissipation mechanism which slows down the field in the last stages. We describe a novel reheating mechanism, which relies on the gauge-boson production leading to strong electromagnetic fields, and proceeds via the vacuum production of electron-positron pairs through the Schwinger effect. We refer to this mechanism as Schwinger reheating. We discuss the cosmological dynamics of the model and the phenomenological constraints from CMB and other experiments. We find that a cutoff close to the Planck scale may be achieved. In its minimal form, the model does not generate sufficient curvature perturbations and additional ingredients, such as a curvaton field, are needed.