منابع مشابه
Dynamics 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...
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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...
متن کاملAtypical k-essence cosmologies
We analyze the implications of having a divergent speed of sound in k-essence cosmological models. We first study a known theory of that kind, for which the Lagrangian density depends linearly on the time derivative of the k-field. We show that consistency requires that the potential of the k-field be of the inverse square form. Then, we review the known result that the corresponding power-law ...
متن کاملPower-law expansion in k-essence cosmology
We study spatially flat isotropic universes driven by k-essence. It is shown that Friedmann and k-field equations may be analytically integrated for arbitrary k-field potentials during evolution with a constant baryotropic index. It follows that there is an infinite number of dynamically different k-theories with equivalent kinematics of the gravitational field. We show that there is a large “w...
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ژورنال
عنوان ژورنال: Classical and Quantum Gravity
سال: 2014
ISSN: 0264-9381,1361-6382
DOI: 10.1088/0264-9381/32/1/015019