Scaling in necklaces of monopoles and semipoles

Abstract

Models of symmetry breaking in the early universe can produce networks of cosmic strings threading 't Hooft-Polyakov monopoles. In certain cases there is a larger global symmetry group and the monopoles split into so-called semipoles. These networks are all known as cosmic necklaces. We carry out large-scale field theory simulations of the simplest model containing these objects, confirming that the energy density of networks of cosmic necklaces approaches scaling, i.e. that it remains a constant fraction of the background energy density. The number of monopoles per unit comoving string length is constant, meaning that the density fraction of monopoles decreases with time. Where the necklaces carry semipoles rather than monopoles, we perform the first simulations large enough to demonstrate that they also maintain a constant number per unit comoving string length. We also compare our results to a number of analytical models of cosmic necklaces, finding that none explains our results. We put forward evidence that annihilation of poles on the strings is controlled by a diffusive process, a possibility not considered before. The observational constraints derived in our previous work for necklaces with monopoles can now be safely applied to those with semipoles as well.

arXiv comment12 pages and 7 figures, updated to match with published version

References in corpus (24)

• Cosmic strings
• Cosmic String Production Towards the End of Brane Inflation
• Cosmic F- and D-strings
• Semilocal and Electroweak Strings
• Quantitative String Evolution
• Extending the Velocity-dependent One-scale String Evolution Model
• Monopoles in the Higgs Phase
• Cosmic Necklaces and Ultrahigh Energy Cosmic Rays
• Scaling from gauge and scalar radiation in Abelian Higgs string networks
• Signals of Inflationary Models with Cosmic Strings
• Seeking String Theory in the Cosmos
• Evolution of cosmic superstring networks: a numerical simulation
• Scaling in a SU(2)/Z_3 model of cosmic superstring networks
• Monopoles on strings
• Evolution of local and global monopole networks
• Semilocal Cosmic String Networks
• Monopole annihilation in cosmic necklaces
• New solutions for non-Abelian cosmic strings
• Numerical simulations of necklaces in SU(2) gauge-Higgs field theory
• Survival of pq-superstrings in field theory simulations
• Evolution of Semilocal String Networks: I. Large-scale Properties
• Formation of Non-Abelian Monopoles Connected by Strings
• Evolution of Cosmic Necklaces and Lattices
• Evolution of Semilocal String Networks: II. Velocity estimators

Cited by in corpus (5)

• Beyond the Standard Models with Cosmic Strings
• Multi-messenger constraints on Abelian-Higgs cosmic string networks
• Baryon-Dark Matter Coincidence in Mirrored Unification
• Revised bounds on local cosmic strings from NANOGrav observations
• Abelian-Higgs Cosmic String Evolution with CUDA