2009/07/31 by Sébastien Renaux‐Petel, Sébastien Renaux-Petel · 2 citations
Physics and Astronomy · #Action (physics) #Angular momentum #Anisotropy #Bispectrum #Black Holes and Theoretical Physics #Born–Infeld model #Brane #Classical mechanics #Cosmic microwave background #Cosmological perturbation theory #Cosmology and Gravitation Theories #Curvature #Equilateral triangle #Galaxies: Formation, Evolution, Phenomena #Geometry #Inflation (cosmology) #Non-Gaussianity #Physics #Planck #Quantum mechanics #Spectral density #Theoretical physics #Trispectrum #astro-ph.CO #gr-qc #hep-th
paper · pdf · doi:10.1088/1475-7516/2009/10/012
published as JCAP 0910:012,2009 · 38 pages, 11 figures. Typos corrected; references added. This version matches the one in press by JCAP
arxiv created 2009/10/16 · openalex publication_date 2009/10/16 · arxiv updated 2014/11/20 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/06
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 NL loc f NL 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.