Quantum corrections to slow-roll inflation: scalar and tensor modes

TL;DR

This paper calculates quantum corrections to the inflationary dynamics of scalar and tensor modes, refining the effective potential and equations governing slow-roll inflation, with implications for models including non-minimal coupling.

Contribution

It provides a detailed computation of quantum corrections to the scalar field equations and Friedmann equations during slow-roll inflation, including tensor modes and non-minimal coupling effects.

Findings

Quantum corrections from scalar and metric perturbations are identified at leading order.

Estimated magnitude of quantum corrections in benchmark inflation models.

Implications for non-minimal coupling to gravity are discussed.

Abstract

Inflation is often described through the dynamics of a scalar field, slow-rolling in a suitable potential. Ultimately, this inflaton must be identified as the expectation value of a quantum field, evolving in a quantum effective potential. The shape of this potential is determined by the underlying tree-level potential, dressed by quantum corrections from the scalar field itself and the metric perturbations. Following [1], we compute the effective scalar field equations and the corrected Friedmann equations to quadratic order in both scalar field, scalar metric and tensor perturbations. We identify the quantum corrections from different sources at leading order in slow-roll, and estimate their magnitude in benchmark models of inflation. We comment on the implications of non-minimal coupling to gravity in this context.