Relaxing inflation models with non-minimal coupling: A general study

TL;DR

This paper classifies inflation models with non-minimal coupling into three categories, deriving their predictions for inflationary observables and providing guidance for constructing models consistent with observations.

Contribution

It offers a general classification framework for non-minimal coupling inflation models and derives their observable predictions, aiding model design.

Findings

Models can be categorized into three classes based on potential and coupling relations.

Each class yields distinctive predictions for spectral index and tensor-to-scalar ratio.

Explicit models illustrate how general features influence observable outcomes.

Abstract

We investigate the predictions of inflation models with a non-minimal coupling to gravity for inflationary observables such as the spectral index and tensor-to-scalar ratio in a general setting. We argue that, depending on the relation between the Jordan frame potential and a function characterizing the non-minimal coupling, one can classify the model into three categories each of which gives distinctive predictions for the inflationary observables. We derive general predictions for each class and also investigate some explicit models to discuss how the general features arise. Our results would be useful to design an inflation model consistent with observational constraints with a non-minimal coupling to gravity.