Non-adiabatic perturbations in decaying vacuum cosmology
Abstract
We investigate a spatially flat Friedmann-Lema\^itre-Robertson-Walker cosmology in which a decaying vacuum term causes matter production at late times. Assuming a decay proportional to the Hubble rate, the ratio of the background energy densities of dark matter and dark energy changes with the cosmic scale factor as . The intrinsically non-adiabatic two-component perturbation dynamics of this model is reduced to a single second-order equation. Perturbations of the vacuum term are shown to be negligible on scales that are relevant for structure formation. On larger scales, dark-energy perturbations give a somewhat higher contribution but remain always smaller than the dark-matter perturbations.
Cite
@article{arxiv.1009.0672,
title = {Non-adiabatic perturbations in decaying vacuum cosmology},
author = {W. Zimdahl and H. A. Borges and S. Carneiro and J. C. Fabris and W. S. Hipólito-Ricaldi},
journal= {arXiv preprint arXiv:1009.0672},
year = {2011}
}
Comments
13 pages, 4 figures, discussion of initial conditions enlarged, accepted for publication in JCAP