Transplanckian inflation as gravity echoes

Understand

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.