Scaling solutions of wiggly cosmic strings
Abstract
Cosmic strings may have formed in the early Universe due to the Kibble mechanism. While string networks are usually modeled as being of NambuGoto type, this description is understood to be a convenient approximation, which neglects the typically expected presence of additional degrees of freedom on the string world sheet. Previous simulations of cosmic strings in expanding universes have established beyond doubt the existence of a significant amount of shortwavelength propagation modes (commonly called wiggles) on the strings, and a wiggly string extension of the canonical velocitydependent onescale model has been recently developed. Here we improve the physical interpretation of this model, by studying the possible asymptotic scaling solutions of this model, and in particular how they are affected by the expansion of the Universe and the available energy loss or transfer mechanisms—e.g., the production of loops and wiggles. In addition to the NambuGoto solution, to which the wiggly model reduces in the appropriate limit, we find that there are also solutions where the amount of wiggliness can grow as the network evolves or, for specific expansion rates, become a constant. Our results show that full scaling of the network, including the wiggliness, is much more likely in the matter era than in the radiation era, which is in agreement with numerical simulation results.
 Publication:

Physical Review D
 Pub Date:
 August 2021
 DOI:
 10.1103/PhysRevD.104.043524
 arXiv:
 arXiv:2107.11653
 Bibcode:
 2021PhRvD.104d3524A
 Keywords:

 Astrophysics  Cosmology and Nongalactic Astrophysics;
 General Relativity and Quantum Cosmology;
 High Energy Physics  Phenomenology
 EPrint:
 13 pages, 4 figures