Decaying Lambda cosmology, varying G and holography
摘要
We discuss a class of uniform and isotropic, spatially flat, decaying Lambda cosmologies, in the realm of a model where the gravitation constant G is a function of the cosmological time. Besides the usual de Sitter solution, the models at late times are characterized by a constant ratio between the matter and total energy densities. One of them presents a coasting expansion where the matter density parameter is equal to 1/3, and the age of the universe satisfies Ht = 1. From considerations in line with the holographic conjecture, it is argued that, among the non-decelerating solutions, the coasting expansion is the only acceptable from a thermodynamic viewpoint, and that the time varying cosmological term must be proportional to the square of the Hubble parameter, a result earlier obtained using different arguments.
引用
@article{arxiv.gr-qc/0405141,
title = {Decaying Lambda cosmology, varying G and holography},
author = {S. Carneiro and J. A. S. Lima},
journal= {arXiv preprint arXiv:gr-qc/0405141},
year = {2010}
}
备注
Minor changes. A short version will appear in the Int. J. Mod. Phys. A (Proceedings of the Sixth Alexander Friedmann International Seminar on Gravitation and Cosmology, Cargese, 2004)