Biaxial Bianchi IX Einstein-Maxwell gravitational instantons: dyonic Taub-NUT/Bolt

Daniel Flores (ICN-UNAM)

Gravitational instantons are solutions to Einstein's equations with a positive definite metric. They are important in the context of Euclidean quantum gravity. They have been used in analogies with quantum field theory, black hole thermodynamics and Ricci flow in General Relativity. In this talk we start with short review of the extended thermodynamics of black holes to include other spacetimes, such as Taub-NUT and Taub-Bolt. We later present the global structure of a dyonic version of these gravitational instantons. The electromagnetic fields under consideration display similarities to the Dirac monopole. We thus present the Dirac quantization condition for these systems.