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arXiv · 1711.09861

Constant-Roll (Quasi-)Linear Inflation

Alexandros Karam·Luca Marzola·Thomas Pappas·Antonio Racioppi·Kyriakos Tamvakis
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Abstract

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 $Δr = 0.001$ 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 $ξ_ϕ\sim 0.29-0.31$ in the model under consideration.

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Alexandros Karam, Luca Marzola, Thomas Pappas, Antonio Racioppi, Kyriakos Tamvakis. 2018-05-05. Constant-Roll (Quasi-)Linear Inflation. https://doi.org/10.1088/1475-7516%2F2018%2F05%2F011

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