Quantum theory and spacetime: allies, not enemies

          @misc{ pirsa_PIRSA:15050078,
            doi = {10.48660/15050078},
            url = {https://pirsa.org/15050078},
            author = {M{\"u}ller, Markus},
            keywords = {Mathematical physics, Quantum Foundations, Quantum Gravity, Quantum Information},
            language = {en},
            title = {Quantum theory and spacetime: allies, not enemies},
            publisher = {Perimeter Institute},
            year = {2015},
            month = {may},
            note = {PIRSA:15050078 see, \url{https://pirsa.org}}
          }
          

Abstract

It has become conventional wisdom to say that quantum theory and gravitational physics are conceptually so different, if not incompatible, that it is very hard to unify them. However, in the talk I will argue that the operational view of (quantum) information theory adds a very different twist to this picture: quite on the contrary, quantum theory and space-time are highly fine-tuned to fit to each other. After a recap of ideas by von Weizsacker, Wootters, and Popescu and Rohrlich, I will show how uncertainty relations, the number of degrees of freedom of the Bloch ball, and the existence of entangled states and possibly the Tsirelson bound can be understood from space-time geometry alone. Conversely, I will show how the 3+1 Lorentz group of space-time can be derived from a purely informational communication scenario of two observers that describe local quantum physics in different Hilbert space bases (joint work with Philipp Hoehn).