Non-adiabatic perturbations in decaying vacuum cosmology

Journal Article · Fri Apr 01 00:00:00 EDT 2011 · Journal of Cosmology and Astroparticle Physics

DOI:https://doi.org/10.1088/1475-7516/2011/04/028· OSTI ID:22277852

Zimdahl, W.; Fabris, J. C. ^[1]; Borges, H. A.; Carneiro, S. ^[2]

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1. Departamento de Física, Universidade Federal do Espírito Santo, Vitória, ES (Brazil)
2. Instituto de Física, Universidade Federal da Bahia, Salvador, BA (Brazil)

We investigate a spatially flat Friedmann-Lemaître-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{sup −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.

• OSTI ID: 22277852
• Journal Information: Journal of Cosmology and Astroparticle Physics, Vol. 2011, Issue 04; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 1475-7516
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
COSMOLOGICAL MODELS
COSMOLOGY
DISTURBANCES
ENERGY DENSITY
FIELD EQUATIONS
NONLUMINOUS MATTER