2007/09/19 by F. Finelli, F. Finelli⋆, Patrick Peter +3 · 1 citation
Physics and Astronomy · #Black Holes and Theoretical Physics #Cosmology and Gravitation Theories #Solar and Space Plasma Dynamics #gr-qc
paper · pdf · doi:10.1103/physrevd.77.103508
published as Phys.Rev.D77:103508,2008 · 11 pages, 5 figures
arxiv created 2007/09/19 · openalex publication_date 2008/05/12 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We introduce analytic solutions for a class of two components bouncing models, where the bounce is triggered by a negative energy density perfect fluid. The equation of state of the two components are constant in time, but otherwise unrelated. By numerically integrating regular equations for scalar cosmological perturbations, we find that the (would-be) growing mode of the Newtonian potential before the bounce never matches with the growing mode in the expanding stage. For the particular case of a negative energy density component with a stiff equation of state we give a detailed analytic study, which is in complete agreement with the numerical results. We also perform analytic and numerical calculations for long wavelength tensor perturbations, obtaining that, in most cases of interest, the tensor spectral index is independent of the negative energy fluid and given by the spectral index of the growing mode in the contracting stage. We compare our results with previous investigations in the literature.