PIRSA:15100067

Oscillations in the CMB bispectrum - Theory and data analysis

Munchmeyer, M. (2015). Oscillations in the CMB bispectrum - Theory and data analysis. Perimeter Institute. https://pirsa.org/15100067

Munchmeyer, Moritz. Oscillations in the CMB bispectrum - Theory and data analysis. Perimeter Institute, Oct. 06, 2015, https://pirsa.org/15100067 

          @misc{ pirsa_PIRSA:15100067,
            doi = {10.48660/15100067},
            url = {https://pirsa.org/15100067},
            author = {Munchmeyer, Moritz},
            keywords = {Cosmology},
            language = {en},
            title = {Oscillations in the CMB bispectrum - Theory and data analysis},
            publisher = {Perimeter Institute},
            year = {2015},
            month = {oct},
            note = {PIRSA:15100067 see, \url{https://pirsa.org}}
          }

Moritz Munchmeyer University of Wisconsin–Madison

DOI 10.48660/15100067
Collection
Talk Type Scientific Series
Subject

Abstract

Oscillating signatures in the correlation functions of the primordial density perturbations are predicted by a variety of inflationary models. A theoretical mechanism that has attracted much attention is a periodic shift symmetry as implemented in axion monodromy inflation. This symmetry leads to resonance non-Gaussianities, whose key feature are logarithmically stretched oscillations. Oscillations are also a generic consequence of excited states during inflation and of sharp features in the potential. Oscillating shapes are therefore a very interesting experimental target. 

After giving an overview of the theoretical motivations, I will discuss how to search for these signatures in the CMB. Fast oscillations are difficult to search for with traditional estimation techniques, and I will demonstrate how targeted expansions, that exploit the symmetry properties of the shapes, allow to circumvent these difficulties. As a member of the Planck collaboration, I will discuss the Planck results that have been obtained using these methods in the bispectrum, as well as related results in the power spectrum. Due to their low overlap with other non-gaussian shapes, oscillating bispectrum shapes are not exhaustively constrained and a potential discovery in the CMB is therefore not yet ruled out.