Beyond General Relativity: Black Holes and Gravitational Waves

Objective

This PhD project aims at exploring some successful and hot topic alternative theories of gravity in what concerns black holes and compact objects, and gravitational waves, specifically from inflation. In particular, one aims at further analyse non-minimal coupling gravity theories with a Weyl connection, which was shown to have interesting properties, namely that the metric field equations are of second order in the derivatives, i.e., free of ghost instabilities. This model has a stable space-form ground state and its vector field can be identified with the electromagnetic vector potential. In its turn, the hybrid metric-Palatini gravity and its generalisation have a rich lore of interesting physical features, in particular, it encompasses a triple unification scenario of inflation, dark matter and dark energy that deserves to be further explored and compared with inflation data from Planck mission.

Therefore, these main classes of alternative theories of gravity constitute relevant theories to assess whether spacetime can be described with more than solely the metric field: with a non-metricity vector field or with an additional affine connection, respectively. Thus, studying its implications for black holes, or compact objects such as gravastars, or its compatibility with data from inflation and gravitational waves, as well as its mathematical stability and existence of solutions pose a quite challenging and crucial research that shall be pursued in this PhD project.
Moreover, it is expected that some outreach activities take place throughout this plan, which will strengthen the Azores Strategy for Space. It will reinforces the collaborations between the University of the Azores, the Astronomical Observatory of Santana-Azores and the schools. This will give visibility of the project at the same time that raises awareness on hot research topics in Physics and Astronomy which are the basis of Space Science and Technology.