Cosmological parameter dependence in local string theories of structure formation

Abstract

We perform a new and accurate study of the dependence on cosmological parameters of structure formation with local cosmic strings. The crucial new ingredients are the inclusion of the effects of gravitational backreaction on the evolution of the network, and the accurate evolution of the network through the radiation to matter transition. Our work re-iterates the fact that expanding Universe numerical simulations only probe a transient regime, and we incorporate our results into the unequal time correlators recently measured. We then compute the CMB and CDM fluctuations' power spectra for various values of the Hubble constant $H_0$ and baryon fraction $Ω_b$. We find that, whereas the dependence on $Ω_b$ is negligible, there is still a strong dependence on $H_0$.