New universal attractor in nonmininally coupled gravity: Linear inflation

TL;DR

This paper demonstrates that quantum loop corrections in certain non-minimally coupled gravity models lead to a universal linear inflation attractor, independent of the metric or Palatini formulation used.

Contribution

It introduces a class of models where loop corrections cause a universal linear inflation attractor, unifying different gravity formulations.

Findings

Loop corrections induce linear inflation attractor.

The attractor is independent of gravity formulation.

Universal behavior across non-minimally coupled models.

Abstract

Once quantum corrections are taken into account, the strong coupling limit of the $\xi$-attractor models (in metric gravity) might depart from the usual Starobinsky solution and move into linear inflation. Furthermore, it is well known that the metric and Palatini formulations of gravity lead to different inflationary predictions in presence of non-minimally couplings between gravity and the inflaton. In this letter we show that for a certain class of non-minimally coupled models, loop corrections will lead to a linear inflation attractor regardless of the adopted gravity formulation.