Cosmology and Gravitation
The field of cosmology and gravitation has rapidly developed during the last decades mainly due to the combination of new ideas in theoretical physics with state of the art high precision data provided by new telescopes, terrestrial observatories and satellites. The combination of data arising from such observations has ensured an unprecedented progress in the field of cosmology and gravitation, by describing our early Universe, its evolution and present state. The group of cosmology and gravitation of the PPGF-UERJ has been conducting research on the main topics of the area, such as:
- numerical relativity
- gravitational radiation
- modified theories of gravitation and gravitation with extra dimensions
- analogue models of gravitation
- gravitational collapse and black holes
- dark energy and dark matter
- inflationary cosmology, primordial cosmology, and the issue of initial conditions of our Universe.
Members:
Henrique Pereira de Oliveira
Interested in nonlinear aspects of GR, gravitational collapse, gravitational waves emission, and initial configurations of astrophysical relevance. The common approach related to all these topics is the application of computational tools like spectral methods, in particular the Galerkin method.
Maria de Fátima Alves da Silva
Interested in gravitational collapse, dark energy stars and gravitating vacuum stars, inhomogeneous cosmology, stationary spacetimes, topology, proper interpretation of exact solutions of Einstein field equations. Also interested in some modified theories of gravitation as Horava-Lifshitz gravity.
Although General Relativity is the most successful theory in order to describe gravitational interaction, there are problems when one considers extreme energy/curvature scales. Among such we can mention the cosmological constant problem, the prediction of an initial singularity for our Universe and the generation of singularities and instabilities in black holes formation. The main interest of my research is related to theories of gravitation in extreme scales so that problems of General Relativity may be circumvented.
Work with emphasis on particle cosmology — the branch of physics that studies the fundamental phenomena of the very small (particle physics) and the very large (the universe). We are interested in the study of various aspects of the physics of the primordial universe. In particular, we carry out studies in inflationary cosmology, cosmological perturbations, late universe physics (e.g., dark matter and dark energy) and primordial phase transitions.
Santiago Esteban Perez Bergliaffa
Regarding cosmology, I’m interested in late-time acceleration without the dark energy hypothesis. In particular, such expansion may be due to inhomogeneous models like Lemâitre-Tolman. Another alternative concerns modified theories of gravitation (as f(R)). In gravitation my work is related to several aspects of black holes (like stability, dynamics and thermodynamics) and exact solutions, propagation of perturbations, and stability of solutions which emerge from modified theories of gravitation, in particular f(R) — both in Palatini and metric formulations. I also work with analogue models of gravitation where I try to infer resemblances between nonlinear electrodynamics and gravitation.