Cosmology

Field of study: Astronomy and physics
Description: In this line of research, we address the issues of dark matter and dark energy by investigating models of modified gravity, models with non-canonical scalar fields, backreaction models, interaction models in the dark sector, and unified dark matter/energy models. We seek to identify characteristic signatures for each class of these models and aim to discriminate between them using observational data. The goal is to obtain more robust evidence regarding the nature of dark matter and dark energy. The tests of theoretical cosmological models using the different available observational data include the CMB, the correlation of large-scale structures, weak lensing, and correlations between these observables. The analysis of modified gravity theories encompasses Horndeski gravity, f(R) theories, non-conservative theories, and gravitational models with torsion and Weyl gravity. This research line also involves studying cosmological inflation and its observational signatures in the CMB. In particular, we investigate extensions of the Starobinsky model and Linde’s alpha-attractors. Besides inflation models, we are also interested in scenarios where there is no singularity (Big Bang), but rather a bounce (bouncing universe). In this case, we focus on predictions for scalar and tensor spectra, non-Gaussianities, and their imprints on the cosmic microwave background, as well as the production of primordial particles and magnetic fields during the bounce.