Department of Physics, Faculty of Science, University of Khartoum, P.O. Box 321, Khartoum 11115, SudanDepartment of Physics and Applied Mathematics, Faculty of Applied Sciences and Computer, Omdurman Ahlia University, P.O. Box 786, Omdurman, Sudan
Phantom Energy with Variable G and Λ
Arbab I. Arbab
Department of Physics, Faculty of Science, University of Khartoum, P.O. Box 321, Khartoum 11115, SudanDepartment of Physics and Applied Mathematics, Faculty of Applied Sciences and Computer, Omdurman Ahlia University, P.O. Box 786, Omdurman, Sudan
摘要We investigate a cosmological model of a phantom energy with a variable cosmological constant (Λ) depending on the energy density (ρ) as Λ∝ρ-α, α=const and a variable gravitational constant G. The model requires α<0 and a negative gravitational constant. The cosmological constant evolves with time as Λ∝t-2. For Ω>-1 and α<-1 the cosmological constant Λ<0, G>0 and ρ decrease with cosmic expansion. For ordinary energy (or dark energy), i.e.~ω>-1, we have -1<α<0 and β>0 so that G>0 increases with time and ρ decreases with time. Cosmic acceleration with dust particles is granted, provided -{2/3}<α<0 and Λ>0.
Abstract：We investigate a cosmological model of a phantom energy with a variable cosmological constant (Λ) depending on the energy density (ρ) as Λ∝ρ-α, α=const and a variable gravitational constant G. The model requires α<0 and a negative gravitational constant. The cosmological constant evolves with time as Λ∝t-2. For Ω>-1 and α<-1 the cosmological constant Λ<0, G>0 and ρ decrease with cosmic expansion. For ordinary energy (or dark energy), i.e.~ω>-1, we have -1<α<0 and β>0 so that G>0 increases with time and ρ decreases with time. Cosmic acceleration with dust particles is granted, provided -{2/3}<α<0 and Λ>0.
(Particle-theory and field-theory models of the early Universe (including cosmic pancakes, cosmic strings, chaotic phenomena, inflationary universe, etc.))
Arbab I. Arbab. Phantom Energy with Variable G and Λ[J]. 中国物理快报, 2008, 25(12): 4497-4500.
Arbab I. Arbab. Phantom Energy with Variable G and Λ. Chin. Phys. Lett., 2008, 25(12): 4497-4500.
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