Effects of Inflation on a Cosmic String Loop Population

TL;DR

This paper investigates how cosmic string loops evolve during inflation, revealing conditions for their survival and behavior, which impacts the understanding of cosmic string networks after inflation.

Contribution

It demonstrates the existence of periodic solutions for circular cosmic string loops in a de Sitter universe and analyzes their survival during inflation.

Findings

Periodic solutions exist for loops with radius below R_c H=1/2.

Larger loops can survive more e-foldings of inflation than point-like objects.

Analogous solutions for domain walls have a critical radius R_c H=2/3.

Abstract

We study the evolution of simple cosmic string loop solutions in an inflationary universe. We show, for the particular case of circular loops, that periodic solutions do exist in a de Sitter universe, below a critical loop radius $R_c H=1/2$. On the other hand, larger loops freeze in comoving coordinates, and we explicitly show that they can survive more $e$-foldings of inflation than point-like objects. We discuss the implications of these findings for the survival of realistic cosmic string loops during inflation, and for the general characteristics of post-inflationary cosmic string networks. We also consider the analogous solutions for domain walls, in which case the critical radius is $R_c H=2/3$.