Observational constraints on Hyperinflation

TL;DR

This paper investigates a hyperinflation model with a hyperbolic field-space, analyzing perturbations and showing that observational constraints significantly limit the model's parameter space.

Contribution

It provides a detailed analysis of perturbations in a hyperinflation model with a hyperbolic field-space, highlighting how observational data restricts model parameters.

Findings

Adiabatic spectral index constrains potential slope.

Hyperbolic field-space affects perturbation evolution.

Allowed background solutions are severely limited.

Abstract

We study a Hyperinflation model involving a field doublet on a hyperbolic field-space manifold and an exponential potential, providing a concise treatment of the evolution of the entropic and adiabatic perturbations around the homogeneous hyperbolic attractor solution. We find that the adiabatic spectral index narrows down the admissible values of the potential's slope to a very small region, severely restricting the state space of the allowed background solutions.