Quantum Corrections to Inflaton and Curvaton Dynamics

TL;DR

This paper calculates quantum corrections to scalar field dynamics during inflation, revealing that such effects can significantly alter the evolution and potentially eliminate inflation at one-loop order.

Contribution

It provides the first fully renormalized one-loop effective action for interacting scalar fields in FRW space-time and explores quantum effects on inflationary dynamics.

Findings

Quantum corrections can significantly modify inflaton evolution.

Curvaton fields are affected mainly by flat-space effective potentials.

Inflation can be suppressed or eliminated due to quantum effects.

Abstract

We compute the fully renormalized one-loop effective action for two interacting and self-interacting scalar fields in FRW space-time. We then derive and solve the quantum corrected equations of motion both for fields that dominate the energy density (such as an inflaton) and fields that do not (such as a subdominant curvaton). In particular, we introduce quantum corrected Friedmann equations that determine the evolution of the scale factor. We find that in general, gravitational corrections are negligible for the field dynamics. For the curvaton-type fields this leaves only the effect of the flat-space Coleman-Weinberg-type effective potential, and we find that these can be significant. For the inflaton case, both the corrections to the potential and the Friedmann equations can lead to behaviour very different from the classical evolution. Even to the point that inflation, although present at tree level, can be absent at one-loop order.