Slow-roll inflation without fine-tuning

TL;DR

This paper demonstrates that for certain inflationary potentials with multiple extrema, the slow-roll condition naturally arises from the requirement of sufficient e-foldings, eliminating the need for it to be assumed separately.

Contribution

It shows that slow-roll inflation can be derived from potential constraints without assuming slow-roll as an initial hypothesis.

Findings

Slow-roll is enforced by e-folding constraints in potentials with multiple extrema.

The usual assumption of slow-roll can be derived rather than assumed.

Implications for inflation model building and observational constraints.

Abstract

The slow-roll approximation is the usual starting point to study the constraints imposed on the inflaton potential parameters by the observational data. We show that, for a potential exhibiting at least two extrema and giving rise to a limited inflationary period, slow-roll does not have to be taken as an additional hypothesis and is in fact forced by the constraints on the number of e-foldings.