Precursor of Inflation

TL;DR

This paper proposes a nonsingular initial universe state within Eddington-inspired Born-Infeld gravity, where a scalar field drives a natural transition to inflation without requiring quantum gravity, resembling chaotic inflation.

Contribution

It introduces a model of the early universe with a nonsingular initial state that naturally evolves into inflation, avoiding quantum gravity complexities.

Findings

Initial state curvature set by scalar field mass scale, below Planck scale

No quantum gravity needed to understand pre-inflationary stage

Model evolves into a long inflationary period similar to chaotic inflation

Abstract

We investigate a nonsingular initial state of the Universe which leads to inflation naturally. The model is described by a scalar field with a quadratic potential in Eddington-inspired Born-Infeld gravity. The curvature of this initial state is given by the mass scale of the scalar field which is much smaller than the Planck scale. Therefore, in this model, quantum gravity is not necessary in understanding this pre-inflationary stage, no matter how large the energy density becomes. The initial state in this model evolves eventually to a long inflationary period which is similar to the usual chaotic inflation.