Monopoles on strings

TL;DR

This paper reviews the physics of monopoles attached to cosmic strings, exploring their types, formation, observational prospects, and potential cosmological significance in early universe models.

Contribution

It provides a comprehensive overview of composite monopole-string objects, including their classifications, formation mechanisms, and observational constraints.

Findings

Various monopole-string configurations like necklaces and dumbbells are classified.

Observational limits on monopole-string structures are summarized.

Potential cosmological roles of these structures are discussed.

Abstract

In cosmological scenarios based on grand unification, string theory or braneworlds, many kinds of topological or non-topological defects, including monopoles and cosmic strings, are predicted to be formed in the early universe. Here we review specifically the physics of composite objects involving monopoles tied to strings. There is a wide variety of these, including for example "dumbbells" and "necklaces," depending on how many strings attach to each monopole and on the extent to which the various fluxes are confined to the strings. We also briefly survey the prospects for observing such structures, the existing observational limits, and potential evidence for a cosmological role.