Local quantum operations and causality

          @misc{ pirsa_PIRSA:18070050,
            doi = {10.48660/18070050},
            url = {https://pirsa.org/18070050},
            author = {Oeckl, Robert},
            keywords = {Quantum Foundations},
            language = {en},
            title = {Local quantum operations and causality},
            publisher = {Perimeter Institute},
            year = {2018},
            month = {jul},
            note = {PIRSA:18070050 see, \url{https://pirsa.org}}
          }
          

Abstract

I give further details on a unification of the foundations of operational quantum theory with those of quantum field theory, coming out of a program that is also known as the positive formalism. I will discuss status and challenges of this program, focusing on the central new concept of local quantum operation. Among the conceptual challenges I want to highlight the question of causality. How do we know that future choices of measurement settings do not influence present measurement results? Should we enforce this, as in the standard formulation of quantum theory? Should this "emerge" from a fundamental theory? Does this question even make sense in a context without a fixed notion of time, such as quantum gravity? With a heavy dose of speculation (put also grounded in very concrete evidence) I find that fermionic theories might play an essential role.