Fine features in the primordial power spectrum

A possible origin of the anomalous dip and bump in the primordial power spectrum, which are reconstructed from WMAP data corresponding to the multipole l = 100 ∼ 140 by using the inversion method, is investigated as a consequence of modification of scalar field dynamics in the inflation era. Utilizing an analytic formula to handle higher order corrections to the slow-roll approximation, we evaluate the relation between a detailed shape of inflaton potential and a fine structure in the primordial power spectrum. We conclude that it is unlikely to generate the observed dip and bump in the power spectrum by adding realistic features in the inflaton potential. In order to generate the fine structure, we find that the slow-roll parameters have to become about O(100) and the number of oscillations in the potential is about O(102), on the scale of the structure