Generalized velocity-dependent one-scale model for current-carrying strings

Multitension strings in high-resolution U(1)$\times$U(1) simulations

“…This has been shown to be the case for the evolution of the simpler cosmic string networks [27,31], and more recent work indicates that this is even more so for analogous models for strings with additional degrees of freedom on the string worldsheet, e.g. wiggly strings [32] and superconducting strings [33,34].…”

Emission of gravitational waves by superconducting cosmic strings

“…The large-scale dynamics of networks of strings with current was studied in detail in [49,50]. Therein, they found that, for fast enough expansion rates, currents are rapidly diluted.…”

“…Performing an accurate characterization of the observational signatures of superconducting cosmic strings, however, is challenging: there are no full superconducting cosmic strings simulations and the cosmological evolution of superconducting JCAP11(2022)024 string networks is still unclear. However, recent progress in the semi-analytical description of the dynamics of networks of current-carrying strings [49,50] allows for a better understanding of how their macroscopic evolution differs from that of standard cosmic string networks.…”

“…In particular, we investigate the gravitational wave emission of cusps, kinks and different types of loops, which allows us to establish a phenomenological relation between Γ and the amplitude of the current that propagates along the cosmic strings. This result, coupled with the semi-analytical model to describe the evolution of currentcarrying strings developed in [49,50], is then used to perform a preliminary study of the impact of current on the stochastic gravitational wave background.…”

“…Although this assumption amounts to assuming that all loops are created with the same length, the results obtained under this assumption may be used to construct n( , t) for any distribution of loop length at the moment of creation, as demonstrated in[83].5 Such a scaling regime is only attainable if there is a mechanism to dissipate current -be it direct leakage or bias[49]. In the absence of such mechanisms, the networks would evolve towards a non-relativistic regime with growing charge.…”