Published online by Cambridge University Press: 30 September 2008
It was Zel'dovich who first clearly realized the importance ofquantum vacuum fluctuations in connection with cosmology. Sincethen, this issue has been more a problem than a solution, even ifthe acceleration of the universe expansion could, in principle, beeasily explained by resorting to it. We have calculated thosecontributions in a number of different models. Under some specificconditions, the results look promising, although a generalacceptable solution looks still far from reach.