Seminar Daan Meerburg

Daan Meerburg
Princeton University
Searching for oscillations in the primordial power spectrum

The Planck data provided unprecedented detail of the small fluctuations in the cosmic microwave background (CMB). We know now
that these fluctuations are adiabatic, Gaussian and almost scale invariant. This constrains models and model parameters of the early
Universe, but despite the quality of the data they remain inconclusive of the details. In particular, small deviations from scale invariance
are still permitted, and so are small levels of non-Gaussianity. In recent years models have been proposed which predict oscillatory
features on top of an almost scale invariant spectrum. The amplitude and frequency of these oscillations is usually associated with
fundamental parameters of the model, be that the axion decay constant in axion-monodromy inflation, or the energy scale at which particles
are injected into the free vacuum during inflation in more exotic models. In this talk I will present a new method to search for these,
potentially really small, features in the CMB data. I will show the method recovers oscillations in Planck-like simulated data at a few
times 10^{-2} level. I will argue that our method is fast, reliable and allows for much more accurate search of features than other
existing methods. After this, I will present our findings after applying this same technique to the WMAP9 and Planck data. I will
address the significance of several intriguing hints in the data, using simulations. If time permits, I will comment on oscillations in light of the BICEP2 results.

Tuesday, April 1, 2014 - 12:30