Non-Gaussianity from inflation - going beyond f_NL-Christian Byrnes (Heidelberg University)

Thursday 12 Nov 2009, 16:00 → 17:15 Europe/Brussels

E/3rd floor-E.349 - Seminar room (E.349) (Marc de Hemptinne (chemin du Cyclotron, 2, Louvain-la-Neuve))

Non-Gaussianity is a powerful and topical way of distinguishing between the many currently viable models of inflation. Perturbations in the cosmic microwave background are already required to be about 99.9% Gaussian and constraints will improve considerably in the next few years. In this talk I show that it is possible to generate a large non-Gaussianity (of the local form) during inflation, both within slow roll, or by a strong break down some of the slow-roll parameters near the end of inflation. An exact solution of two-field inflation is provided in the latter case. Finally I discuss some "higher-order" non-Gaussian parameters, such as a scale dependence of the bispectrum (3-point function) and the trispectrum. Constraints on these further observables would be very powerful in further breaking the degeneracy between inflationary models.