2004/10/31 by Robert J. Scherrer · 1 citation
Physics and Astronomy · #Cosmology and Gravitation Theories #Dark Matter and Cosmic Phenomena #Galaxies: Formation, Evolution, Phenomena #astro-ph #gr-qc #hep-th
paper · pdf · doi:10.1103/physrevd.71.063519
published as Phys.Rev. D71 (2005) 063519 · 4 pages, 1 figure, more references and discussion added, to appear in Phys. Rev. D
arxiv created 2005/03/10 · openalex publication_date 2005/03/18 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Phantom dark-energy models, with w<\ensuremath-1, are characterized by a future singularity and therefore a finite lifetime for the universe. Because the future singularity is triggered by the onset of dark-energy domination, the universe spends a significant fraction of its total lifetime in a state for which the dark-energy and matter densities are roughly comparable. We calculate, as a function of w, the fraction of the total lifetime of the universe for which the dark-energy and matter densities differ by less than the ratio r0 in either direction. For r0=10, this fraction varies from 1/3 to 1/8 as w varies from \ensuremath-1.5 to \ensuremath-1.1; the fraction is smaller for smaller values of r0. This result indicates that the coincidence problem is significantly ameliorated in phantom-dominated cosmologies with a future singularity.