Abstract
The phenomenological approach to investigate the decay of the effective cosmological constant, as recently proposed by Chen and Wu, is generalized to include a term proportional to on the time dependence of , where is the Hubble parameter. This new term can modify some features of the standard Friedmann-Robertson-Walker model and its free parameter may be adjusted in accordance with nucleosynthesis constraints. The model also allows a deceleration parameter assuming negative values so that the density parameter is smaller than ⅔ and the age of the Universe is always bigger than . In these cases, the usual matter creation rate appearing in models with a decaying vacuum energy is smaller than the one present in the steady-state model.
- Received 27 March 1992
DOI:https://doi.org/10.1103/PhysRevD.46.2404
©1992 American Physical Society