Cosmology with variable parameters and effective equation of state for dark energy
نویسندگان
چکیده
منابع مشابه
Cosmology with variable parameters and effective equation of state for Dark Energy
A cosmological constant, Λ, is the most natural candidate to explain the origin of the dark energy (DE) component in the Universe. However, due to experimental evidence that the equation of state (EOS) of the DE could be evolving with time/redshift (including the possibility that it might behave phantom-like near our time) has led theorists to emphasize that there might be a dynamical field (or...
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Equation of state parameter plays a significant role for guessing the real nature of dark energy. In the present paper polytropic equation of state p = ωρn is chosen for some of the kinematical Λ-models viz., Λ ∼ (ȧ/a), Λ ∼ ä/a and Λ ∼ ρ. Although in dust cases (ω = 0) closed form solutions show no dependency on the polytropic index n, but in non-dust situations some new possibilities are opene...
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We perform a study of cosmic evolution with an equation of state parameter ω(t) = ω0 + ω1(tḢ/H) by selecting a phenomenological Λ model of the form, Λ̇ ∼ H. This simple proposition explains both linearly expanding and inflationary Universes with a single set of equations. We notice that the inflation leads to a scaling in the equation of state parameter, ω(t), and hence in equation of state. In ...
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ژورنال
عنوان ژورنال: Journal of Physics A: Mathematical and General
سال: 2006
ISSN: 0305-4470,1361-6447
DOI: 10.1088/0305-4470/39/21/s76