Chargevelocitydependent onescale linear model
Abstract
We apply a recently developed formalism to study the evolution of a currentcarrying string network under the simple but generic assumption of a linear equation of state. We demonstrate that the existence of a scaling solution with nontrivial current depends on the expansion rate of the Universe, the initial rootmeansquare current on the string, and the available energyloss mechanisms. We find that the fast expansion rate after radiationmatter equality will tend to rapidly dilute any preexisting current, and the network will evolve towards the standard NambuGoto scaling solution (provided there are no external currentgenerating mechanisms). During the radiation era, current growth is possible provided the initial conditions for the network generate a relatively large current and/or there is significant early string damping. The network can then achieve scaling with a stable nontrivial current, assuming large currents will be regulated by some leakage mechanism. The potential existence of currentcarrying string networks in the radiation era, unlike the standard NambuGoto networks expected in the matter era, could have interesting phenomenological consequences.
 Publication:

Physical Review D
 Pub Date:
 November 2021
 DOI:
 10.1103/PhysRevD.104.103506
 arXiv:
 arXiv:2108.03147
 Bibcode:
 2021PhRvD.104j3506M
 Keywords:

 Astrophysics  Cosmology and Nongalactic Astrophysics
 EPrint:
 21 pages, 9 figures