Comparing parametric and nonparametric velocitydependent onescale models for domain wall evolution
Abstract
We perform a detailed comparison between a recently proposed parameterfree velocitydependent onescale model and the standard parametric model for the cosmological evolution of domain wall networks. We find that the latter overestimates the damping of the wall motion due to the Hubble expansion and neglects the direct impact of wall decay on the evolution of the rootmeansquare velocity of the network. We show that these effects are significant but may be absorbed into a redefinition of the momentum parameter. We also discuss the implications of these findings for cosmic strings. We compute the energy loss and momentum parameters of the standard parametric model for cosmological domain wall evolution using our {nonparametric} velocitydependent onescale model in the context of cosmological models having a power law evolution of the scale factor a with the cosmic time t (a propto t^{λ}, 0 < λ < 1), and compare with the results obtained from numerical field theory simulations. We further provide simple linear functions which roughly approximate the dependence of the energy loss and momentum parameters on λ.
 Publication:

Journal of Cosmology and Astroparticle Physics
 Pub Date:
 April 2020
 DOI:
 10.1088/14757516/2020/04/012
 arXiv:
 arXiv:2001.06318
 Bibcode:
 2020JCAP...04..012A
 Keywords:

 Astrophysics  Cosmology and Nongalactic Astrophysics;
 General Relativity and Quantum Cosmology;
 High Energy Physics  Phenomenology;
 High Energy Physics  Theory
 EPrint:
 12 pages, 4 figures. Matches published version in JCAP. arXiv admin note: text overlap with arXiv:1910.07011