Super exponential inflation from a dynamical foliation of a 5D vacuum state

TL;DR

This paper proposes a model of super exponential inflation derived from a 5D vacuum metric, leading to a universe that accelerates rapidly and transitions to a de Sitter phase, with unique scalar fluctuation spectra.

Contribution

It introduces a novel 5D geometric framework for super exponential inflation with specific predictions for fluctuation spectra.

Findings

The model describes a super accelerated early universe expansion.

Scalar fluctuation spectra are not scale invariant, with different behaviors at cosmological and astrophysical scales.

The universe tends to a de Sitter expansion at large times.

Abstract

We introduce super exponential inflation ($\omega < -1$) from a 5D Riemann-flat canonical metric on which we make a dynamical foliation. The resulting metric describes a super accelerated expansion for the early universe well-known as super exponential inflation that, for very large times, tends to an asymptotic de Sitter (vacuum dominated) expansion. The scalar field fluctuations are analyzed. The important result here obtained is that the spectral index for energy density fluctuations is not scale invariant, and for cosmological scales becomes $n_s(k<k_*) \simeq 1$. However, for astrophysical scales this spectrum changes to negative values $n_s(k>k_*) <0 $.