2017/11/30 by A. Karam, Alexandros Karam, L. Marzola +7 · 5 citations
Physics and Astronomy · #Black Holes and Theoretical Physics #Cosmological constant #Cosmology and Gravitation Theories #Coupling (piping) #Galaxies: Formation, Evolution, Phenomena #Hubble's law #Inflation (cosmology) #Inflaton #Minimal coupling #Scalar (mathematics) #Scalar field #Universe #Upper and lower bounds #astro-ph.CO #gr-qc #hep-ph
paper · pdf · doi:10.1088/1475-7516/2018/05/011
2 figures and a few comments added, matches version published in JCAP
openalex created_date 2017/12/04 · openalex publication_date 2018/05/03 · arxiv created 2018/05/05 · arxiv updated 2018/05/08 · openalex updated_date 2026/08/06
In constant-roll inflation, the scalar field that drives the accelerated expansion of the Universe is rolling down its potential at a constant rate. Within this framework, we highlight the relations between the Hubble slow-roll parameters and the potential ones, studying in detail the case of a single-field Coleman-Weinberg model characterised by a non-minimal coupling of the inflaton to gravity. With respect to the exact constant-roll predictions, we find that assuming an approximate slow-roll behaviour yields a difference of Δ r = 0.001 in the tensor-to-scalar ratio prediction. Such a discrepancy is in principle testable by future satellite missions. As for the scalar spectral index n s , we find that the existing 2-σ bound constrains the value of the non-minimal coupling to ξ ϕ ∼ 0.29–0.31 in the model under consideration.