Planck Constraints on Monodromy Inflation

TL;DR

Using Planck data, we constrain features in the primordial power spectrum from monodromy inflation, finding no significant evidence for such signals and highlighting the need for further comparative and theoretical studies.

Contribution

This study provides the first constraints on monodromy inflation modulations using Planck data, improving upon previous WMAP analyses and clarifying the significance of potential signals.

Findings

No significant primordial signal detected in Planck data.

The fit improvement is smaller than in WMAP9, consistent with noise expectations.

Results motivate further comparison and theoretical work on monodromy inflation.

Abstract

We use data from the nominal Planck mission to constrain modulations in the primordial power spectrum associated with monodromy inflation. The largest improvement in fit relative to the unmodulated model has \Delta\chi^2~10 and we find no evidence for a primordial signal, in contrast to a previous analysis of the WMAP9 dataset, for which \Delta\chi^2~20. The Planck and WMAP9 results are broadly consistent on angular scales where they are expected to agree as far as best-fit values are concerned. However, even on these scales the significance of the signal is reduced in Planck relative to WMAP, and is consistent with a fit to the noise associated with cosmic variance. Our results motivate both a detailed comparison between the two experiments and a more careful study of the theoretical predictions of monodromy inflation.