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

Understand

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.