What is needed of a tachyon if it is to be the dark energy?

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dc.creatorCopeland, Edmund J.
dc.creatorGarousi, Mohammad R.
dc.creatorSami, M.
dc.creatorTsujikawa, Shinji
dc.date2004-11-22
dc.date2005-01-28
dc.date.accessioned2026-07-07T10:30:06Z
dc.date.available2026-07-07T10:30:06Z
dc.descriptionWe study a dark energy scenario in the presence of a tachyon field $ϕ$ with potential $V(ϕ)$ and a barotropic perfect fluid. The cosmological dynamics crucially depends on the asymptotic behavior of the quantity $λ=-M_pV_ϕ/V^{3/2}$. If $λ$ is a constant, which corresponds to an inverse square potential $V(ϕ) \propto ϕ^{-2}$, there exists one stable critical point that gives an acceleration of the universe at late times. When $λ\to 0$ asymptotically, we can have a viable dark energy scenario in which the system approaches an ``instantaneous'' critical point that dynamically changes with $λ$. If $|λ|$ 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 $|λ|$ is smaller than of order unity.
dc.description11 pages and 3 figures, minor clarifications added; final version to appear in PRD
dc.identifierhttps://arxiv.org/abs/hep-th/0411192
dc.identifierhttp://arxiv.org/abs/hep-th/0411192
dc.identifierPhys.Rev.D71:043003,2005
dc.identifierdoi:10.1103/PhysRevD.71.043003
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/178032
dc.subjectHigh Energy Physics - Theory
dc.subjectAstrophysics
dc.subjectGeneral Relativity and Quantum Cosmology
dc.subjectHigh Energy Physics - Phenomenology
dc.titleWhat is needed of a tachyon if it is to be the dark energy?
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