Spherically Symmetric Inflation

TL;DR

This paper demonstrates that in a spherically symmetric inhomogeneous universe with a massive scalar field, a sufficiently large homogeneous patch is necessary to initiate inflation, regardless of initial conditions, confirming the robustness of previous results.

Contribution

It generalizes prior findings by showing the requirement of a large homogeneous patch for inflation in inhomogeneous geometries with spherical symmetry.

Findings

A homogeneous patch larger than ten horizons is needed to start inflation.

Results are independent of initial scalar field distribution.

Initial metric conditions are justified and consistent.

Abstract

It is shown in this letter that in the framework of an inhomogeneous geometry and a massive non self-interacting scalar field with spherical symmetry, one needs a homogeneous patch bigger than a dizaine of horizons in order to start inflation. The results are completly independent of initial conditions on the spatial distribution of the scalar field. The initial condition on the metric parameters are also justified. This is a generalization of the results obtained in Ref.[1], showing that their conclusions are rather robust.