Revising the predictions of inflation for the cosmic microwave background anisotropies

TL;DR

This paper shows that accounting for quantum field renormalization during inflation significantly alters predictions for the cosmic microwave background anisotropies, impacting the tensor-to-scalar ratio and spectral indices.

Contribution

It introduces a revised approach to inflation predictions by incorporating quantum renormalization effects evaluated near horizon crossing, challenging standard results.

Findings

Revised inflation predictions differ from standard models.

Both $f{\phi^2}$ and $f{\phi^4}$ potentials align with WMAP data.

Alternative predictions may be testable by future experiments.

Abstract

We point out that if quantum field renormalization is taken into account, and the counterterms are evaluated at the Hubble-radius crossing time or few e-foldings after it, the predictions of slow-roll inflation for both the scalar and tensorial power spectrum change significantly. This leads to a change in the consistency condition that relates the tensor-to-scalar amplitude ratio with spectral indices. A reexamination of the potentials $\bf{\phi^2, \phi^4}$, shows that both are compatible with five-year WMAP data. Only when the counterterms are evaluated at much larger times beyond the end of inflation one recovers the standard predictions. The alternative predictions presented here may soon come within the range of measurement of near-future experiments.