Intermediate inflation from a non-canonical scalar field

TL;DR

This paper explores a non-canonical scalar field model of intermediate inflation, demonstrating its compatibility with Planck 2015 data, estimating the inflation energy scale, and addressing the issue of eternal inflation.

Contribution

It introduces a non-canonical framework for intermediate inflation that aligns with observational data and proposes a solution to the inflation ending problem.

Findings

Model compatible with Planck 2015 results

Estimated initial energy scale near Planck energy

Proposed mechanism for ending inflation

Abstract

We study the intermediate inflation in a non-canonical scalar field framework with a power-like Lagrangian. We show that in contrast with the standard canonical intermediate inflation, our non-canonical model is compatible with the observational results of Planck 2015. Also, we estimate the equilateral non-Gaussianity parameter which is in well agreement with the prediction of Planck 2015. Then, we obtain an approximation for the energy scale at the initial time of inflation and show that it can be of order of the Planck energy scale, i.e. ${M_P} \sim {10^{18}}\,{\rm{GeV}}$. We will see that after a short period of time, inflation enters in the slow-roll regime that its energy scale is of order ${M_P}/100 \sim \;{10^{16}}{\rm{GeV}}$ and the horizon exit takes place in this energy scale. We also examine an idea in our non-canonical model to overcome the central drawback of intermediate inflation which is the fact that inflation never ends. We solve this problem without disturbing significantly the nature of the intermediate inflation until the time of horizon exit.