# Helical phase inflation and its observational constraints

## TL;DR

This paper explores a class of supergravity-based helical phase inflation models where the inflaton is the phase of a complex field, demonstrating their compatibility with observational data and their connection to $eta$-attractors.

## Contribution

It introduces a novel class of supergravity inflation models utilizing phase monodromy, showing their observational viability and relation to $eta$-attractors.

## Key findings

- Models fit Planck 2018 and BICEP2 data
- Inflationary predictions depend on a single parameter
- Models exhibit $eta$-attractor behavior

## Abstract

We consider a class of helical phase inflation models from the ${\mathcal N}=1$ supergravity where the phase component of a complex field acts as an inflaton. This class of models avoids the eta problem in supergravity inflation due to the phase monodromy of the superpotential. We study the inflationary predictions of this class of models in the context of both standard and large extra dimensional brane cosmology, and find that they can easily accommodate the Planck 2018 and BICEP2 constraints. We find that the helical phase inflation has $\alpha$-attractors and the attractors depend on one model parameter only.