Can the curvaton paradigm accommodate a low inflation scale?

TL;DR

This paper investigates whether the curvaton paradigm can be adapted to low inflation scales by exploring strong couplings that could lower the required Hubble parameter during inflation.

Contribution

It proposes a mechanism allowing the curvaton paradigm to function at lower inflation scales by involving strong couplings to fields with large post-inflation values.

Findings

The standard curvaton bound of H > 10^7 GeV can be evaded.

Strong couplings to fields at the end of inflation enable low-scale inflation models.

Potential improvements in the viability of low-scale inflation scenarios.

Abstract

The cosmological curvature perturbation may be generated when some `curvaton' field, different from the inflaton, oscillates in a background of unperturbed radiation. In its simplest form the curvaton paradigm requires the Hubble parameter during inflation to be bigger than $10^7\GeV$, but this bound may be evaded if the curvaton field (or an associated tachyon) is strongly coupled to a field which acquires a large value at the end of inflation. As a result the curvaton paradigm might be useful in improving the viability of low-scale inflation models, in which the supersymmetry-breaking mechanism is the same as the one which operates in the vacuum.