Why is all physics quantum, i.e. described by the counterintuitive formalism of complex state vectors and operators? How is quantum theory ultimately combined with spacetime physics? These questions are of fundamental importance in the foundations of physics, including quantum information theory and quantum gravity. In this talk, I describe a research program that aims at tackling aspects of both questions at once. I begin with results that derive quantum theory from simple information-theoretic principles, starting from a large class of probabilistic theories. Not only does this shed light on the first question above, but it also puts a remarkable insight center stage: that the structures of spacetime and of abstract quantum theory are surprisingly intertwined. Here, I explain how this relation can be analyzed in simple thought experiments, show that it can give us an exact characterization of the (2,2,2)-quantum Bell correlations, and argue that it holds the promise for new quantum information protocols and experimental tests of quantum theory.
