Shaft inflation in Randall-Sundrum model

TL;DR

This paper explores shaft inflation within the Randall-Sundrum II model, demonstrating that its predictions align well with observations and determining a consistent five-dimensional Planck scale.

Contribution

It introduces the study of shaft inflation in the RSII model and finds its predictions match observations, providing insights into extra-dimensional cosmology.

Findings

Predictions agree with observational data

Five-dimensional Planck scale estimated at ~10^{16} GeV

Consistent with experimental bounds on gravity

Abstract

Shaft inflation is a model in which the inflaton potential approaches a plateau far from the origin, while it resembles chaotic inflation near the origin. Meanwhile, the Randall-Sundrum type II model (RSII) is an interesting extra-dimensional model to study cosmological phenomenology. In this paper, we study shaft inflation in the RSII model. We find that the predictions are in excellent agreement with observation. The fundamental five-dimensional Planck scale is found to be $M_5\simeq 10^{16}$ GeV, which is consistent with the lower bound $M_5\gtrsim 10^{9}$ GeV obtained from experimental Newtonian gravitational bound. This is an important result that can be used to explore further the implications of extra dimension in other contexts.