Linear perturbations in a universe with a cosmological constant
نویسندگان
چکیده
We study the linear theory of perturbations in a Friedmann-Robertson-Walker universe with a cosmological constant. We obtain the equations for the evolution of the perturbations in the fully relativistic case, for which we analyze the single-fluid and the two-fluid cases. We obtain solutions to these equations in appropriate limits. We also study the Newtonian approximation. We find that for a positive cosmological constant universe (i) the perturbations will grow slower in the relativistic regime for a two-fluid composed of dark matter and radiation, and (ii) in the Newtonian regime, the perturbations stop growing.
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