Effect of damped oscillations in the inflationary potential

Abstract

We investigate the effect of damped oscillations on a nearly flat inflationary potential and the features they produce in the power-spectrum and bi-spectrum. We compare the model with the Planck data using Plik unbinned and CamSpec clean likelihood and we are able to obtain noticeable improvement in fit compared to the power-law $\Lambda$CDM model. We are able to identify three plausible candidates each for the two likelihoods used. We find that the best-fit to Plik and CamSpec likelihoods match closely to each other. The improvement comes from various possible outliers at the intermediate to small scales. We also compute the bi-spectrum for the best-fits. At all limits, the amplitude of bi-spectrum, $f_{NL}$ is oscillatory in nature and its peak value is determined by the amplitude and frequency of the oscillations in the potential, as expected. We find that the bi-spectrum consistency relation strictly holds at all scales in all the best-fit candidates.