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Title: Combined local and equilateral non-Gaussianities from multifield DBI inflation

Abstract

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.

Authors:
 [1]
  1. APC (UMR 7164, CNRS, Université Paris 7), 10 rue Alice Domon et Léonie Duquet, 75205 Paris Cedex 13 (France)
Publication Date:
OSTI Identifier:
22273063
Resource Type:
Journal Article
Journal Name:
Journal of Cosmology and Astroparticle Physics
Additional Journal Information:
Journal Volume: 2009; Journal Issue: 10; Other Information: Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 1475-7516
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; 72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; AMPLITUDES; ASTROPHYSICS; BORN-INFELD THEORY; COSMOLOGY; D-BRANES; DISTURBANCES; FLUCTUATIONS; INFLATIONARY UNIVERSE; TACHYONS

Citation Formats

Renaux-Petel, Sébastien. Combined local and equilateral non-Gaussianities from multifield DBI inflation. United States: N. p., 2009. Web. doi:10.1088/1475-7516/2009/10/012.
Renaux-Petel, Sébastien. Combined local and equilateral non-Gaussianities from multifield DBI inflation. United States. https://doi.org/10.1088/1475-7516/2009/10/012
Renaux-Petel, Sébastien. 2009. "Combined local and equilateral non-Gaussianities from multifield DBI inflation". United States. https://doi.org/10.1088/1475-7516/2009/10/012.
@article{osti_22273063,
title = {Combined local and equilateral non-Gaussianities from multifield DBI inflation},
author = {Renaux-Petel, Sébastien},
abstractNote = {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.},
doi = {10.1088/1475-7516/2009/10/012},
url = {https://www.osti.gov/biblio/22273063}, journal = {Journal of Cosmology and Astroparticle Physics},
issn = {1475-7516},
number = 10,
volume = 2009,
place = {United States},
year = {2009},
month = {10}
}