The essay “Accelerating universe as a result of an adjustment mechanism”, written in collaboration with Nelson J. Nunes, has been awarded honorable mention in the Gravity Research Foundation essay competition 2015. In this essay we propose that the theory of gravity’s vacuum is described by a de Sitter geometry. Under this assumption we consider an adjustment mechanism able to screen any value of the vacuum energy of the matter fields. We discuss the most general scalar-tensor cosmological models with second order equations of motion that have a fixed de Sitter critical point for any kind of material content. These models give rise to interesting cosmological evolutions that we also discuss.
The essay is available here.