Transplanckian inflation as gravity echoes

TL;DR

This paper demonstrates that non-minimal coupling to gravity allows single-field inflation models to produce large tensor modes without transplanckian field values, challenging previous assumptions about the necessity of such values.

Contribution

It introduces three simple single-field models with non-minimal coupling that generate significant tensor modes without transplanckian field values, within the slow-roll regime.

Findings

Large tensor-to-scalar ratio achieved without transplanckian fields

Non-minimal coupling alters the need for transplanckian field values

Models are consistent with experimental results

Abstract

In this work, we show that, in the presence of non-minimal coupling to gravity, it is possible to generate sizeable tensor modes in single-field models without transplanckian field values. These transplanckian field values apparently needed in Einstein gravity to accommodate the experimental results may only be due to our insistence of imposing a minimal coupling of the inflaton field to gravity in a model with non-minimal couplings. We present three simple single-field models that prove that it is possible accommodate a large tensor-to-scalar ratio without requiring transplanckian field values within the slow-roll regime.