Fundamental physics probed via high-energy collisions of electrically charged black holes

Ultra-relativistic collisions of black holes are ideal settings where to investigate how general relativity behaves under extreme conditions. A large fraction of the allowed parameter space has been explored over the past 13 years (including mass, spin, impact parameter), with the notable exception of charge. The inclusion of charge is significant because it adds non trivial degrees of freedom to the system. For example, charge constitutes another way to reach extremality (together with spin) and opens up a new channel to radiate away energy (through electromagnetic waves). Moreover, charge makes the study more directly relevant to particle physics and the production of microscopic black holes in cosmic rays and in particle accelerators. In this talk, I am going to present the first numerical-relativity simulations of head-on collisions of black holes with the same charge and mass. In particular, I am going to discuss what they can teach us about a variety of conjectures, including cosmic censorship and the role of the inner structure of bodies colliding at relativistic speed.