ACCELERATED EXPANSION OF THE UNIVERSE DRIVEN BY TACHYONIC MATTER

By Thanu Padmanabhan. 2002

846 citations recorded by the source corpus.

It is an accepted practice in cosmology to invoke a scalar field with a potential $V(\ensuremath{\varphi})$ when the 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 $V(\ensuremath{\varphi}),$ it is always possible to find a scalar field potential which will reproduce a given evolution. I provide a recipe for determining $V(\ensuremath{\varphi})$ from $a(t)$ in two cases: (i) a normal scalar field with the Lagrangian $\mathcal{L}=(1/2){\ensuremath{\partial}}_{a}\ensuremath{\varphi}{\ensuremath{\partial}}^{a}\ensuremath{\varphi}\ensuremath{-}V(\ensuremath{\varphi})$ used in quintessence or dark energy models; (ii) a tachyonic field with the Lagrangian $\mathcal{L}=\ensuremath{-}V(\ensuremath{\varphi})[1\ensuremath{-}{\ensuremath{\partial}}_{a}\ensuremath{\varphi}\ensuremath{\partial}{}^{a}\ensuremath{\varphi}{]}^{1/2},$ 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.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/37f756ec3774532c417160968daec905d6d47065

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Citations in the corpus

A Bird's Eye View of f (R)-Gravity (2009, background): “Interesting examples are the generalized Chaplygin gas [36], the tachyon field [37] and the condensate cosmology [38].”
Coupling of rolling tachyon to closed strings (2002, neutral): “1E-mail: takuya@theory.caltech.edu 2E-mail: sugimoto@nbi.dk”
Structure formation in inhomogeneous dark energy models (2004, background): “Other authors (Padmanabhan 2002; Padmanabhan & Choudhury 2002; Bagla, Jassal & Padmanabhan 2003; Causse 2003) discussed more exotic models, based on tachyon fields, and argued that the equation of state is scaledependent.”
Schwarzschild black hole surrounded by quintessence: null geodesics (2012, background): “but not limited to, quintessence [8], chameleon fields [9], K-essence [10], tachyon field [11], phantom dark energy [12] and dilaton dark energy [13].”
Cluster number counts dependence on dark energy inhomogeneities and coupling to dark matter (2005, background): “In Padmanabhan & Choudhury (2002); Padmanabhan (2002); Bagla et al (2003) and Causse (2003) more exotic models, based on tachyon fields, have been discussed and they argued that the quintessence equation of state is scale– dependent.”
Dynamical systems applied to cosmology: Dark energy and modified gravity (2017, background): “Applications of tachyonic scalar fields to late time cosmology were considered soon after they arose from high-energy physics (Padmanabhan, 2002; Gibbons, 2002, 2003; Bagla et al., 2003; Gorini et al., 2004).”
Problems with Tachyon Inflation (2002, background): “In papers [24, 25] inflation was considered for phenomenological potentials V (T ) hat have not been derived in the string tachyon theory.”
WMAP and the generalized Chaplygin gas (2003, background): “Recently, the tachyon field (with V = V (ϕ)) motivated from string theory has received a lot of attention (Sen 2002, Gibbons 2002, Padmanabhan 2002).”