2011/11/30 by Joel M. Weller, Carsten van de Bruck, David F. Mota · 24 citations
Physics and Astronomy · #Amplitude #Black Holes and Theoretical Physics #Cosmological perturbation theory #Cosmology and Gravitation Theories #Galaxies: Formation, Evolution, Phenomena #Geometry #Inflation (cosmology) #Inflaton #Mathematical physics #Parameter space #Physics #Quantum electrodynamics #Quantum mechanics #Scalar (mathematics) #Scalar field #Slow roll #Spectral density #Spectral index #Spectral line #Tensor (intrinsic definition) #Theoretical physics #astro-ph.CO #hep-th
paper · pdf · doi:10.1088/1475-7516/2012/06/002
published in Journal of Cosmology and Astroparticle Physics 2012(06), 002 (Institute of Physics) · Analytical discussion clarified, matches published version. (23 pages incl. appendices, 9 figures)
arxiv created 2012/05/31 · openalex publication_date 2012/06/01 · arxiv updated 2012/06/04 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
The scalar-tensor Dirac-Born-Infeld (DBI) inflation scenario provides a simple mechanism to reduce the large values of the boost factor associated with single field models with DBI action, whilst still being able to drive 60 efolds of inflation. Using a slow-roll approach, we obtain an analytical expression for the spectral index of the perturbations and, moreover, determine numerically the regions of the parameter space of the model capable of giving rise to a power spectrum with amplitude and spectral index within the observed bounds. We find that regions that exhibit significant DBI effects throughout the inflationary period can be discarded by virtue of a blue-tilted spectral index, however, there are a number of viable cases — associated with a more red-tilted spectral index — for which the boost factor is initially suppressed by the effect of the coupling between the fields, but increases later to moderate values.