Orador: Alexander Zhuk (University of Odessa). Data, hora e local: 19 de Outubro de 2015, às 14h30m na sala de reuniões do Departamento de Matemática.

Resumo: We consider the late Universe deep inside the cell of uniformity. At these scales, the Universe is highly inhomogeneous and is filled with discrete distributed structures (galaxies, groups and clusters of galaxies), which perturb the background Friedmann model. We investigate such Universe in the mechanical approach. This means that the peculiar velocities of the inhomogeneities in the form of galaxies as well as fluctuations of other perfect fluids are nonrealistic. Under such condition, we investigate the theory of scalar perturbations. We derive the main equations and apply them to a number of models, starting with the LambdaCDM model. We demonstrate that within our approach, the theory of scalar perturbations is a good tool to select viable dark energy models.

Funded by the Portuguese Government through the FCT – Fundação para a Ciência e a Tecnologia under the project UID/MAT/00212/2013