Heterotic Cosmic Strings

TL;DR

This paper demonstrates that heterotic cosmic strings originating from M5-branes in heterotic M-theory can meet all conditions for cosmological relevance, overcoming issues faced by weakly coupled heterotic strings.

Contribution

It introduces a novel class of heterotic cosmic strings from M5-branes that satisfy tension, stability, and production criteria in the strongly coupled regime.

Findings

Strings from M5-branes meet cosmological conditions.

Weakly coupled heterotic strings face unresolved problems.

M-theory regime provides a consistent framework for cosmic strings.

Abstract

We show that all three conditions for the cosmological relevance of heterotic cosmic strings, the right tension, stability and a production mechanism at the end of inflation, can be met in the strongly coupled M-theory regime. Whereas cosmic strings generated from weakly coupled heterotic strings have the well known problems posed by Witten in 1985, we show that strings arising from M5-branes wrapped around 4-cycles (divisors) of a Calabi-Yau in heterotic M-theory compactifications, solve these problems in an elegant fashion.