Power-law expansion in k-essence cosmology
Abstract
We study spatially flat isotropic universes driven by k-essence. It is shown that Friedmann and k-field equations may be analytically integrated for arbitrary k-field potentials during evolution with a constant baryotropic index. It follows that there is an infinite number of dynamically different k-theories with equivalent kinematics of the gravitational field. We show that there is a large "window" of stable solutions, and that the dust-like behaviour separates stable from unstable expansion. Restricting to the family of power law solutions, it is argued that the linear scalar field model, with constant function F, is isomorphic to a model with divergent speed of sound and this makes them less suitable for cosmological modeling than the non-linear k-field solutions we find in this paper.
Cite
@article{arxiv.astro-ph/0305007,
title = {Power-law expansion in k-essence cosmology},
author = {Luis P. Chimento and Alexander Feinstein},
journal= {arXiv preprint arXiv:astro-ph/0305007},
year = {2009}
}
Comments
Revised version. A detailed discussion relating the power-law solutions with the linear K-essence field and inverse square potential, on one hand, and the models with divergent sound volocity, on the other, is added