Gurzadyan Vahe

I.C.R.A.Net- International Center for Relativistic Astrophysics Network, University of Rome "La Sapienza"

Title: Relevant vacuum modes, dark energy and observations

Abstract: Certain observational consequencies of the dark energy density, as of a contribution of relevant vacuum fluctuations, will be discussed.

Orchidea Maria Lecian

*University of Rome "La Sapienza"

*I.C.R.A.- International Center for Relativistic Astrophysics

Title: Accelerated universe from an exponential Lagrangian of the metric field.

Authors: Orchidea Maria Lecian*, Giovanni Montani*

Speaker: Orchidea Maria Lecian

Abstract: Generalized Einstein equations are calculated for an exponential gravitational action, and the results are illustrated to be equivalent to a higher-order variational calculation in FRW metric. Such an action is explained to be in line with the features of the present accelerated universe. Semi-analytical de Sitter-like solutions are found for the considered dynamics, and compared to numerical ones. A comparison between standard and modified FRW cosmology is provided, thus outlining the main achievement of our formulation.