Spherical Curvature Inhomogeneities in String Cosmology

TL;DR

This paper investigates the evolution of spherical inhomogeneities in string cosmology, analyzing their behavior in different phases and implications for primordial black hole formation.

Contribution

It introduces a method to match Friedmann solutions with varying curvature to study non-linear inhomogeneities in string cosmology.

Findings

Bound and unbound inhomogeneities evolve differently.

Patterns of evolution are characterized in pre- and post-big-bang phases.

Implications for primordial black hole formation are discussed.

Abstract

We study the evolution of non-linear spherically symmetric inhomogeneities in string cosmology. Friedmann solutions of different spatial curvature are matched to produce solutions which describe the evolution of non-linear density and curvature inhomogeneities. The evolution of bound and unbound inhomogeneities are studied. The problem of primordial black hole formation is discussed in the string cosmological context and the pattern of evolution is determined in the pre- and post-big-bang phases of evolution.