Inflation without Slow Roll

TL;DR

This paper explores the possibility that inflation can persist after slow roll ends, during rapid inflaton oscillations, potentially affecting reheating and primordial perturbations in cosmology.

Contribution

It introduces a scenario where inflation continues during inflaton oscillations due to a specific potential condition, impacting reheating and primordial spectra.

Findings

Inflation can extend beyond slow roll during inflaton oscillations.

Oscillation-driven inflation can alter reheating scenarios.

Potential imprints on primordial perturbation spectrum at large scales.

Abstract

We draw attention to the possibility that inflation (i.e. accelerated expansion) might continue after the end of slow roll, during a period of fast oscillations of the inflaton field \phi . This phenomenon takes place when a mild non-convexity inequality is satisfied by the potential V(\phi). The presence of such a period of \phi-oscillation-driven inflation can substantially modify reheating scenarios. In some models the effect of these fast oscillations might be imprinted on the primordial perturbation spectrum at cosmological scales.