TY - JOUR

T1 - Interacting cosmic fluids in power-law Friedmann-Robertson-Walker cosmological models

AU - Cataldo, Mauricio

AU - Mella, Patricio

AU - Minning, Paul

AU - Saavedra, Joel

N1 - Funding Information:
This work was supported by Grants FONDECYT 1051086 (M.C.), 11060515 (J.S.), grant CONICYT 21070462 (P.M.), and by Dirección de Investigación de la Universidad del Bío–Bío (M.C.). The financial support of Escuela de Graduados of the Universidad de Concepción is also acknowledged (P.M.).

PY - 2008/5/1

Y1 - 2008/5/1

N2 - 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 / t2. 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.

AB - 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 / t2. 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.

UR - http://www.scopus.com/inward/record.url?scp=42049114244&partnerID=8YFLogxK

U2 - 10.1016/j.physletb.2008.03.022

DO - 10.1016/j.physletb.2008.03.022

M3 - Article

AN - SCOPUS:42049114244

SN - 0370-2693

VL - 662

SP - 314

EP - 322

JO - Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics

JF - Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics

IS - 4

ER -