Inflation from a massive scalar field and scalar perturbations of the metric

TL;DR

This paper investigates how a massive scalar field influences inflationary density fluctuations, showing that super Hubble fluctuations grow during inflation, consistent with previous power-law universe models.

Contribution

It introduces a semiclassical approach to derive metric and matter fluctuations for a massive scalar field during chaotic inflation, extending prior analyses.

Findings

Super Hubble density fluctuations increase during inflation.

Results align with previous power-law universe models.

Provides a new derivation method for fluctuations.

Abstract

In the framework of chaotic inflation we study the case of a massive scalar field using a semiclassical approach. We derive the energy density fluctuations in the infrared sector generated by matter field and gauge-invariant metric fluctuations by means of a different method. We find that the super Hubble density fluctuations increase during inflation for a massive scalar field, in agreement with the result obtained in a previous work in which a power-law expanding universe was considered.