Assisted Chaotic Inflation in Higher Dimensional Theories

TL;DR

This paper proposes a model of assisted chaotic inflation using multiple scalar fields from higher-dimensional theories, allowing inflation with sub-Planckian initial field values and avoiding non-renormalizable interaction issues.

Contribution

It introduces a higher-dimensional framework where KK modes enable assisted inflation with lower initial field values, addressing limitations of traditional chaotic inflation models.

Findings

Inflation can be achieved with initial fields below the Planck scale.

KK modes from extra dimensions assist in driving inflation.

Non-renormalizable interactions are effectively mitigated.

Abstract

We address the problem of the large initial field values in chaotic inflation and propose a remedy in the framework of the so-called assisted inflation. We demonstrate that a 4-dimensional theory of multiple, scalar fields with initial field values considerably below the Planck scale, can give rise to inflation even though none of the individual scalar fields are capable of driving inflation. The problems arising from the presence of possible non-renormalizable interactions is therefore removed. As a concrete example of a theory with multiple scalar fields, we consider a (4+d)-dimensional field theory of a single, non-interacting massive scalar field whose KK modes play the role of the assisted sector. For the KK modes to assist inflation, the extra dimensions must have a size larger than the inverse (4D) Planck scale.