Göttingen 2012 – scientific programme

Parts | Days | Selection | Search | Updates | Downloads | Help

GR: Fachverband Gravitation und Relativitätstheorie

GR 3: Kosmologie II

GR 3.2: Talk

Monday, February 27, 2012, 17:00–17:20, ZHG 002

Anatomy of bispectra in general single-field inflation --- modal expansions — •Jan Grieb and Thorsten Battefeld — Institut für Astrophysik, Göttingen, Deutschland

Non-Gaussianities are an important probe of the interactions in the very early universe. This work discusses bispectra of single-field inflationary models described by general Lorentz invariant Lagrangians that are at most first order in field derivatives, including the fast-roll models investigated by Noller and Magueijo. We identify the least correlated basic contributions to the general shape and show quantitatively which templates provide a good approximation. Future comparison with CMB observations requires modal techniques for these non-separable bispectra. In the context of this work, we provide a modal expansion employing the formalism by Fergusson et al.

Truncated polynomial modal expansions have restrictions, which we highlight using an example with slow convergence. The particular shape originates from particle production during inflation (common in trapped inflation) and entails both localized and oscillatory features. We show that this shape can be recovered efficiently using a Fourier basis.