2004/11/30 by Edmund J. Copeland, Mohammad R. Garousi, M. Sami +1 · 265 citations
Mathematics · Physics and Astronomy · #Acceleration #Black Holes and Theoretical Physics #Classical mechanics #Cosmological constant #Cosmology #Cosmology and Gravitation Theories #Dark energy #Energy (signal processing) #Geometry #Infinity #Inverse #Lambda #Mathematical analysis #Mathematical physics #Mathematics #Order (exchange) #Physics #Quantum mechanics #Solar and Space Plasma Dynamics #Tachyon #astro-ph #gr-qc #hep-ph #hep-th
paper · pdf · doi:10.1103/physrevd.71.043003
published in Physical review. D. Particles, fields, gravitation, and cosmology/Physical review. D. Particles and fields 71(4) (American Physical Society) · 11 pages and 3 figures, minor clarifications added; final version to appear in PRD
arxiv created 2005/01/28 · openalex publication_date 2005/02/10 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We study a dark energy scenario in the presence of a tachyon field \ensuremathφ with potential V(\ensuremathφ) and a barotropic perfect fluid. The cosmological dynamics crucially depends on the asymptotic behavior of the quantity \ensuremathλ=\ensuremath-MpV_\ensuremathφ/V3/2. If \ensuremathλ is a constant, which corresponds to an inverse square potential V(\ensuremathφ)\ensuremath∝\ensuremathφ^\ensuremath-2, there exists one stable critical point that gives an acceleration of the Universe at late times. When \ensuremathλ\ensuremath→0 asymptotically, we can have a viable dark energy scenario in which the system approaches an instantaneous critical point that dynamically changes with \ensuremathλ. If |\ensuremathλ| approaches infinity asymptotically, the Universe does not exhibit an acceleration at late times. In this case, however, we find an interesting possibility that a transient acceleration occurs in a regime where |\ensuremathλ| is smaller than of order unity.