منابع مشابه
N ov 2 00 4 Quintessence as k - essence
Quintessence and k-essence have been proposed as candidates for the dark energy component of the universe that would be responsible of the currently observed accelerated expansion. In this paper we investigate the degree of resemblance between those two theoretical setups and find that every quintessence model can be viewed as a k-essence model generated by a kinetic linear function. In additio...
متن کاملTracking quintessence and k-essence in a general cosmological background
We derive conditions for stable tracker solutions for both quintessence and k-essence in a general cosmological background, H ∝ f(ρ). We find that tracker solutions are possible only when η ≡ d ln f/d ln ρ ≈ constant, aside from a few special cases, which are enumerated. Expressions for the quintessence or k-essence equation of state are derived as a function of η and the equation of state of t...
متن کاملThe Essence of Quintessence and the Cost of Compression
Standard two-parameter compressions of the infinite dimensional dark energy model space show crippling limitations even with current SN-Ia data. Firstly they cannot cope with rapid evolution our best-fit to the latest SN-Ia data shows late and very rapid evolution to w0 = −2.85. However all of the standard parametrisations (incorrectly) claim that this best-fit is ruled out at more than 2σ prim...
متن کاملDynamics of K-essence
There are a number of mathematical theorems in the literature on the dynamics of cosmological models with accelerated expansion driven by a positive cosmological constant Λ or a nonlinear scalar field with potential V (quintessence) which do not assume homogeneity and isotropy from the beginning. The aim of this paper is to generalize these results to the case of k-essence models which are defi...
متن کاملReconstructing K-essence
We present a model independent method of reconstructing the Lagrangian for the k-essence field driving the present acceleration of the universe. We consider the simplest k-essence model for which the potential is constant. Later we use three parametrizations for the Hubble parameter H(z), consistent with recent the SN1a data, to yield the Lagrangian F . Our reconstruction program does not gener...
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ژورنال
عنوان ژورنال: Physics Letters B
سال: 2005
ISSN: 0370-2693
DOI: 10.1016/j.physletb.2005.10.011