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arXiv · 1009.0672

Non-adiabatic perturbations in decaying vacuum cosmology

W. Zimdahl·H. A. Borges·S. Carneiro·J. C. Fabris·W. S. Hipólito-Ricaldi
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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 $a^{-3/2}$. 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.

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W. Zimdahl, H. A. Borges, S. Carneiro, J. C. Fabris, W. S. Hipólito-Ricaldi. 2010-09-03. Non-adiabatic perturbations in decaying vacuum cosmology. https://doi.org/10.1088/1475-7516/2011/04/028

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