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arXiv · 0803.1086

Interacting cosmic fluids in power-law Friedmann-Robertson-Walker cosmological models

Mauricio Cataldo·Patricio Mella·Paul Minning·Joel Saavedra
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Abstract

We provide a detailed description for power--law scaling Friedmann-Robertson-Walker cosmological scenarios dominated by two interacting perfect fluid components during the expansion. As a consequence of the mutual interaction between the two fluids, neither component is conserved separately and the energy densities are proportional to $1/t^{2}$. It is shown that in flat FRW cosmological models there can exist interacting superpositions of two perfect fluids (each of them having a positive energy density) which accelerate the expansion of the universe. In this family there also exist flat power law cosmological scenarios where one of the fluids may have a ``cosmological constant" or "vacuum energy" equation of state ($p =-ρ$) interacting with the other component; this scenario exactly mimics the behavior of the standard flat Friedmann solution for a single fluid with a barotropic equation of state. These possibilities of combining interacting perfect fluids do not exist for the non-interacting mixtures of two perfect cosmic fluids, where the general solution for the scale factor is not described by power--law expressions and has a more complicated behavior. In this study is considered also the associated single fluid model interpretation for the interaction between two fluids.

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Mauricio Cataldo, Patricio Mella, Paul Minning, Joel Saavedra. 2008-03-07. Interacting cosmic fluids in power-law Friedmann-Robertson-Walker cosmological models. https://doi.org/10.1016/j.physletb.2008.03.022

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