Combined local and equilateral non-Gaussianities from multifield DBI inflation
- APC (UMR 7164, CNRS, Université Paris 7), 10 rue Alice Domon et Léonie Duquet, 75205 Paris Cedex 13 (France)
We study multifield aspects of Dirac-Born-Infeld (DBI) inflation. More specifically, we consider an inflationary phase driven by the radial motion of a D-brane in a conical throat and determine how the D-brane fluctuations in the angular directions can be converted into curvature perturbations when the tachyonic instability arises at the end of inflation. The simultaneous presence of multiple fields and non-standard kinetic terms gives both local and equilateral shapes for non-Gaussianities in the bispectrum. We also study the trispectrum, pointing out that it acquires a particular momentum dependent component whose amplitude is given by f{sub NL}{sup loc} f{sub NL}{sup eq}. We show that this relation is valid in every multifield DBI model, in particular for any brane trajectory, and thus constitutes an interesting observational signature of such scenarios.
- OSTI ID:
- 22273063
- Journal Information:
- Journal of Cosmology and Astroparticle Physics, Vol. 2009, Issue 10; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 1475-7516
- Country of Publication:
- United States
- Language:
- English
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