2009/09/30 by Takeshi Chiba · 2 citations
Mathematics · Physics and Astronomy · #Advanced Differential Geometry Research #Cosmology and Gravitation Theories #Mathematical Biology Tumor Growth #astro-ph.CO #gr-qc #hep-ph
paper · pdf · doi:10.1103/physrevd.81.023515
published as Phys.Rev.D81:023515,2010 · 5 pages, 2 figures
arxiv created 2010/01/07 · openalex publication_date 2010/01/15 · arxiv updated 2010/04/06 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We derive the equation of state of tracker fields, which are typical examples of freezing quintessence (quintessence with the equation of state approaching toward \ensuremath-1), taking into account of the late-time departure from the tracker solution due to the nonzero density parameter of dark energy \ensuremathΩ_\ensuremathφ. We calculate the equation of state as a function of \ensuremathΩ_\ensuremathφ for constant \ensuremathΓ=VV^\ensuremath'\ensuremath'/(V^\ensuremath')2 (during matter era) models. The derived equation of state contains a single parameter, w(0), which parametrizes the equation of state during the matter-dominated epoch. We derive observational constraints on w(0) and find that observational data are consistent with the cosmological constant: \ensuremath-1.11<w(0)<\ensuremath-0.96(1\ensuremathσ).