2002/11/28 by Daniela Carturan, D. Carturan, F. Finelli⋆ +1 · 6 citations
Physics and Astronomy · #Black Holes and Theoretical Physics #Cosmology and Gravitation Theories #Galaxies: Formation, Evolution, Phenomena #astro-ph #gr-qc #hep-ph #hep-th
paper · pdf · doi:10.1103/physrevd.68.103501
published as Phys.Rev. D68 (2003) 103501 · 4 pages, 6 figures
arxiv created 2002/11/28 · openalex publication_date 2003/11/07 · arxiv updated 2009/11/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We study the impact of a generalized Chaplygin gas as a candidate for dark energy on density perturbations and on cosmic microwave background (CMB) anisotropies. The generalized Chaplygin gas is a fluid component with an exotic equation of state p=\ensuremath-A/\ensuremathρ^\ensuremathα (a polytropic gas with negative constant and exponent). Such a component interpolates in time between dust and a cosmological constant, with an intermediate behavior as p=A^1/(1+\ensuremathα)+\ensuremathα\ensuremathρ. Perturbations of this fluid are stable on small scales but behave in a very different way with respect to standard quintessence. Moreover, a generalized Chaplygin gas could also represent an archetypal example of the phenomenological unified models of dark energy and dark matter. The results presented here show how CMB anisotropies and density perturbations in this class of models differ from those of a cold dark matter model with a cosmological constant.