Cosmological Evolution of Semilocal String Networks

TL;DR

This paper investigates the cosmological evolution of semilocal string networks, proposing a new model for their scaling behavior and supporting it with preliminary numerical evidence.

Contribution

It introduces a novel model for the evolution and scaling of semilocal string networks, including segments, with initial numerical validation.

Findings

Proposed a thermodynamic-like model for semilocal string network evolution.

Numerical evidence supports the model's predictions.

Identified the dynamic behavior of segments within the network.

Abstract

Semilocal strings -- a particular limit of electroweak strings -- are an interesting example of a stable non-topological defect whose properties resemble those of their topological cousins, the Abrikosov-Nielsen-Olesen vortices. There is, however, one important difference: a network of semilocal strings will contain segments. These are 'dumbbells' whose ends behave almost like global monopoles that are strongly attracted to one another. While closed loops of string will eventually shrink and disappear, the segments can either shrink or grow, and a cosmological network of semilocal strings will reach a scaling regime. We discuss attempts to find a "thermodynamic" description of the cosmological evolution and scaling of a network of semilocal strings, by analogy with well-known descriptions for cosmic strings and for monopoles. We propose a model for the time evolution of an overall lengthscale and typical velocity for the network as well as for its segments, and some supporting (preliminary) numerical evidence.