The observational position of simple non-minimally coupled inflationary scenarios

TL;DR

This paper analyzes two classes of non-minimally coupled inflation models, focusing on their attractor structures and viability constraints from BICEP2 B-mode polarization data.

Contribution

It provides a detailed analysis of attractor structures in non-minimal inflation models and assesses their observational viability under BICEP2 data interpretations.

Findings

Identified a shift of the attractor from the Starobinsky point.

Determined conditions for approach to the attractor.

Found strong constraints on non-minimal coupling from BICEP2 data.

Abstract

We consider two classes of non-minimally coupled inflation models; those with a quadratic coupling of the inflaton to gravity, and the `Universal Attractor' models where the coupling is connected to the potential. We make a detailed analysis of the attractor structure in the latter case, identifying a shift of the attractor from the Starobinsky point and determining conditions for approach to the attractor. We then assess the viability of the models under different interpretations of the BICEP2 experiment's detection of B-mode polarisation, finding strong constraints on the non-minimal coupling in the case where the B-modes have mostly primordial origin.