Reheating in small-field inflation on the brane: The Swampland Criteria and observational constraints in light of the PLANCK 2018 results

TL;DR

This paper examines small-field inflation models within brane cosmology, testing their compatibility with Planck 2018 data and Swampland Criteria, and explores implications for reheating and leptogenesis.

Contribution

It provides a detailed analysis of four inflationary potentials in brane cosmology, constrains parameters with observational data, and assesses their consistency with Swampland conjectures.

Findings

Distance conjecture is satisfied.

De Sitter conjecture can be avoided.

Allowed five-dimensional Planck mass range is 10^5 to 10^12 TeV.

Abstract

We study cosmological inflation and its dynamics in the framework of the Randall-Sundrum II brane model. In particular, we analyze in detail four representative small-field inflationary potentials, namely Natural inflation, Hilltop inflation, Higgs-like inflation, and Exponential SUSY inflation, each characterized by two mass scales. We constrain the parameters for which a viable inflationary Universe emerges using the latest PLANCK results. Furthermore, we investigate whether or not those models in brane cosmology are consistent with the recently proposed Swampland Criteria, and give predictions for the duration of reheating as well as for the reheating temperature after inflation. Our results show that (i) the distance conjecture is satisfied, (ii) the de Sitter conjecture and its refined version may be avoided, and (iii) the allowed range for the five-dimensional Planck mass, $M_5$, is found to be between $10^5~\textrm{TeV}$ and $10^{12}~\textrm{TeV}$. Our main findings indicate that non-thermal leptogenesis cannot work within the framework of RS-II brane cosmology, at least for the inflationary potentials considered here.