The Revival of Cosmic Strings

TL;DR

This paper reviews recent developments in cosmic string research, highlighting their potential formation in supersymmetric theories, observational support, and renewed interest due to new theoretical and empirical insights.

Contribution

It summarizes recent progress showing cosmic strings can form in supersymmetric theories and discusses their revived role in cosmology.

Findings

Cosmic strings can be formed in supersymmetric grand unified theories.

Cosmic superstrings may act as cosmic strings.

Recent observational hints support the existence of cosmic strings.

Abstract

Cosmic strings are one-dimensional topological defects which could have been formed in the early stages of our Universe. They triggered a lot of interest, mainly for their cosmological implications: they could offer an alternative to inflation for the generation of density perturbations. It was shown however that cosmic strings lead to inconsistencies with the measurements of the cosmic microwave background temperature anisotropies. The picture is changed recently. It was shown that, on the one hand, cosmic strings can be generically formed in the framework of supersymmetric grand unified theories and that, on the other hand, cosmic superstrings could play the r\^ole of cosmic strings. There is also some possible observational support. All this lead to a revival of cosmic strings research and this is the topic of my lecture.