Single field inflation with modulated potential in light of the Planck and BICEP2

TL;DR

This paper proposes a single field inflation model with a modulated potential that can reconcile the tension between Planck and BICEP2 data by producing a large tensor-to-scalar ratio and negative spectral index running, consistent with observations.

Contribution

It introduces a novel single field inflation model with a modulated potential that explains both the BICEP2 and Planck observations, addressing their apparent tension.

Findings

Model produces a large tensor-to-scalar ratio.

Model exhibits a sizable negative running of the spectral index.

Numerical results agree with current CMB data.

Abstract

The recently released BICEP2 data detected the primordial B-mode polarization in the Cosmic Microwave Background (CMB) map which strongly supports for a large tensor-to-scalar ratio, and thus, is found to be in tension with the Planck experiment with no evidence of primordial gravitational waves. Such an observational tension, if confirmed by forthcoming measurements, would bring a theoretical challenge for the very early universe models. To address this issue, we in the present paper revisit a single field inflation model, which includes a modulated potential. We show that this inflation model can give rise to a sizable negative running behavior for the spectral index of primordial curvature perturbation and a large tensor-to-scalar ratio. Applying these properties, our model can nicely explain the combined Planck and BICEP2 observations. To examine the validity of analytic calculations, we numerically confront the predicted temperature and B-mode power spectra with the latest CMB observations and explicitly show that our model is consistent with the current data.