Unitarity, Unimodular Time and Resolution of Singularities

This lecture by Steffen Gielen from the University of Sheffield explores fundamental principles in quantum gravity theories, focusing on the concept of unitarity in time evolution. Delve into various approaches to implementing unitarity in quantum cosmology and black hole models. Discover how specific notions of unitarity, particularly those utilizing unimodular gravity's time coordinate, can lead to the resolution of classical singularities by replacing them with quantum transitions from past universes or into future white holes. The presentation examines the challenges of defining unitarity in quantum gravity contexts and offers insights into how these theoretical frameworks might address some of the most profound questions in theoretical physics.