0 M ay 1 99 6 OUTP - 96 - 16 P Nucleosynthesis Bounds on a Time – varying Cosmological “ Constant ”
نویسنده
چکیده
We constrain proposed phenomenological models for a vacuum energy which decays with the expansion of the universe from considerations of standard big bang nucleosynthesis. Several models which are simple enough to be physically appealing are ruled out. Typeset using REVTEX
منابع مشابه
ar X iv : a st ro - p h / 96 05 17 6 v 1 2 9 M ay 1 99 6 A time – dependent “ Cosmological Constant ”
We construct a cosmological toy model in which a step-function “cosmological constant” is taken into consideration beside ordinary matter. We assume that Λ takes two values depending on the epoch, and matter goes from a radiation dominated era to a dust dominated era. The model is exactly solvable and it can be compared with recent observations. PACS: 98.80. Cq, 98.70. Vc e-mail address: capozz...
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متن کاملar X iv : a st ro - p h / 98 05 25 7 v 2 2 0 M ay 1 99 8 Light – Element Nucleosynthesis : Big Bang and Later on
Production of the light nuclides D, 3 He, 4 He, and 7 Li in their currently inferred primordial abundances by standard, homogeneous big bang nucle-osynthesis (SHBBN) would imply a baryon fraction of the cosmic closure density Ω b in the range: 0.04 ≤ Ω b h 2 50 ≤ 0.08 (1) where h 50 is the Hubble constant in units of 50 km s −1 Mpc −1 [1], [2]. Therefore, for the long–time most generally favore...
متن کاملar X iv : a st ro - p h / 98 05 25 7 v 1 1 9 M ay 1 99 8 Light – Element Nucleosynthesis : Big Bang and Later on
Production of the light nuclides D, 3 He, 4 He, and 7 Li in their currently inferred primordial abundances by standard, homogeneous big bang nucle-osynthesis (SHBBN) would imply a baryon fraction of the cosmic closure density Ω b in the range: 0.04 ≤ Ω b h 2 50 ≤ 0.08 (1) where h 50 is the Hubble constant in units of 50 km s −1 Mpc −1 [1], [2]. Therefore, for the long–time most generally favore...
متن کاملar X iv : a st ro - p h / 00 05 40 6 v 1 1 9 M ay 2 00 0 IFP - 784 - UNC astro - ph / 0005406 May 2000 Quintessence and CMB
A particular kind of quintessence is considered, with equation of motion pQ/ρQ = −1, corresponding to a cosmological term with time-dependence Λ(t) = Λ(t0)(R(t0)/R(t)) P which we examine initially for 0 ≤ P < 3. Energy conservation is imposed, as is consistency with big-bang nucleosynthesis, and the range of allowed P is thereby much restricted to 0 ≤ P < 0.2. The position of the first Doppler ...
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