Artigo de Periódico
Non-adiabatic perturbations in decaying vacuum cosmology
Fecha
2011Registro en:
1475-7516
sem v.
Autor
Carneiro, Saulo
Borges, H. A.
Zimdahl, W.
Fabris, J. C.
Ricaldi, W. S. Hipólito
Carneiro, Saulo
Borges, H. A.
Zimdahl, W.
Fabris, J. C.
Ricaldi, W. S. Hipólito
Institución
Resumen
We investigate a spatially flat Friedmann-Lemaˆıtre-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.