Conditions for inflation in an initially inhomogeneous universe

TL;DR

This paper investigates the initial conditions necessary for inflation to occur in an inhomogeneous universe, using Einstein's equations and a scalar field to determine the threshold of inhomogeneities that can prevent inflation.

Contribution

It introduces a long wavelength iteration scheme to analyze how initial inhomogeneities influence the onset of inflation in the early universe.

Findings

Identifies the maximum initial inhomogeneity amplitude compatible with inflation.

Provides a quantitative criterion for inhomogeneity thresholds.

Shows that certain inhomogeneities can delay or prevent inflation.

Abstract

Using a long wavelength iteration scheme to solve Einstein's equations near the Big-Bang singularity of a universe driven by a massive scalar field, we find how big initial quasi-isotropic inhomogeneities can be before they can prevent inflation to set in.