Stability of superconducting strings coupled to cosmic strings

TL;DR

This paper investigates the stability of superconducting strings coupled to cosmic strings within a specific gauge field model, revealing how interaction strength affects perturbation speeds and current-carrying capabilities, with implications for cosmic string network evolution.

Contribution

It provides a numerical analysis of how gauge interactions influence the stability and current properties of superconducting strings coupled to cosmic strings, a novel aspect in string stability studies.

Findings

Propagation speed of perturbations varies with interaction strength.

Superconducting strings cannot carry magnetic currents under certain conditions.

Model offers a field theory realization of bound states relevant to cosmic string networks.

Abstract

We study the stability of superconducting strings in a U(1)_{local} x U(1)_{global} model coupled via a gauge field interaction term to U(1) Abelian-Higgs strings. The effect of the interaction on current stability is numerically investigated by varying the relevant parameters within the physical limits of our model. We find that the propagation speed of transverse (resp. longitudinal) perturbations increases (decreases) with increasing binding between the superconducting and Abelian-Higgs string. Moreover, we observe that for small enough width of the flux tube of the superconducting string and/or large enough interaction between the superconducting and the Abelian-Higgs string superconducting strings cannot carry space-like, i.e. magnetic currents. Our model can be seen as a field theoretical realization of bound states of p F-strings and q superconducting D-strings and has important implications to vorton formation during the evolution of networks of such strings.