Cora Dvorkin (IAS)

Complete WMAP Constraints on Inflationary Features

In this talk, I introduce a general method for constraining the shape of the inflationary potential from Cosmic Microwave Background (CMB) temperature and polarization power spectra. This approach relates the CMB observables to the shape of the inflationary potential via a single source function that is responsible for the observable features in the initial curvature power spectrum. The source function is, to an excellent approximation, simply related to the slope and curvature of the inflaton potential, even in the presence of large or rapidly changing deviations from scale-free initial conditions. Oscillatory features in the CMB temperature power spectrum have been interpreted as possible evidence for new physics during inflation. It has been shown that a model with a sharp step in the inflationary potential can give rise to these oscillations, but such cases are typically studied on a case-by-case basis. This formalism generalizes previous studies by exploring the complete parameter space of inflationary models in a single analysis.

Using a principal component basis that accommodates order unity features across more than 2 decades of the inflationary expansion, I test slow roll and single field inflation with the WMAP 7-year dataset. I present model-independent predictions for the matching glitches in the polarization spectrum that would test their inflationary origin. Even allowing for the presence of features in the temperature spectrum, single field inflation makes sharp falsifiable predictions for the acoustic peaks in the polarization whose violation would require extra degrees of freedom. This analysis greatly simplifies the testing of inflationary models in that it can be used to constrain parameters of specific models of inflation without requiring a separate likelihood analysis for each choice.