Accelerated expansion of the universe driven by tachyonic matter

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dc.creatorPadmanabhan, T.
dc.date2002-04-18
dc.date.accessioned2026-07-07T10:34:13Z
dc.date.available2026-07-07T10:34:13Z
dc.descriptionIt is an accepted practice in cosmology to invoke a scalar field with potential $V(ϕ)$ when observed evolution of the universe cannot be reconciled with theoretical prejudices. Since one function-degree-of-freedom in the expansion factor $a(t)$ can be traded off for the function $V(ϕ)$, it is {\it always} possible to find a scalar field potential which will reproduce a given evolution. I provide a recipe for determining $V(ϕ)$ from $a(t)$ in two cases:(i) Normal scalar field with Lagrangian ${\cal L} = (1/2)\partial_aϕ\partial^aϕ- V(ϕ)$ used in quintessence/dark energy models. (ii) A tachyonic field with Lagrangian ${\cal L} = -V(ϕ) [ 1- \partial_aϕ\partial^aϕ]^{1/2} $, motivated by recent string theoretic results. In the latter case, it is possible to have accelerated expansion of the universe during the late phase in certain cases. This suggests a string theory based interpretation of the current phase of the universe with tachyonic condensate acting as effective cosmological constant.
dc.description4 pages; uses revtex4
dc.identifierhttps://arxiv.org/abs/hep-th/0204150
dc.identifierhttp://arxiv.org/abs/hep-th/0204150
dc.identifierPhys.Rev.D66:021301,2002
dc.identifierdoi:10.1103/PhysRevD.66.021301
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/179400
dc.subjectHigh Energy Physics - Theory
dc.subjectAstrophysics
dc.subjectGeneral Relativity and Quantum Cosmology
dc.titleAccelerated expansion of the universe driven by tachyonic matter
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