Black holes, cosmology, and spacetime singularities in non-Riemannian extensions of General Relativity


  • Call:

    IDPASC Portugal - PHD Programme 2017

  • Academic Year:

    2017 / 2018

  • Domains:

    General Relativity | Cosmology

  • Supervisor:

    Diego Rubiera-Garcia

  • Co-Supervisor:

    Francisco Lobo

  • Institution:

    Faculdade de Ciências - Universidade de Lisboa

  • Host Institution:

    Institute of Astrophysics and Space Sciences (Faculty of Sciencies)

  • Abstract:

    Einstein’s deep insight on the relation between gravitation and geometry represents the culmination of scientific thinking on the nature of gravitation initiated with the pioneering works of Galileo. The predictions of his General Theory of Relativity (GR) are in excellent agreement with numerous astrophysical and cosmological observations. Nonetheless, the limits and validity of GR are currently under question. On the theoretical side, GR is clearly unable to provide a consistent description of both the innermost region of black holes and the early Universe, where a spacetime singularity unavoidably develops, threatening determinism and causality. On the phenomenological side, we find the inability of GR and the standard model of particle physics to account for both dark matter and dark energy, of which we have no direct experimental evidence so far. This PhD Thesis proposal will address these questions from a wider perspective, where we admit a larger freedom in the geometric elements underlying the theory, which are not usually considered in the standard formulation of GR. This way, we will consider non-Riemannian geometries in gravitational actions extending the one of GR (including, but not limited to, higher-order curvature theories, like f(R)), and put them to work to discuss in detail the black hole, astrophysical and cosmological modifications in the corresponding theories. A major goal of this Thesis is the understanding of spacetime singularities beyond GR within black holes and in the early Universe, as well as finding mechanisms for their (classical) resolution. This Thesis takes place at the Institute of Astrophysics and Space Sciences at Lisbon University, and involves collaborations with researchers at the University of Valencia (Spain), the Institute of Space Sciences at Barcelona University (Spain), and the Paraíba Federal University (Brazil), among others, with whom the PhD student will be able to interact.