Local states and channels in causal theories

          @misc{ scivideos_PIRSA:11050058,
            doi = {10.48660/11050058},
            url = {https://pirsa.org/11050058},
            author = {Perinotti, Paolo},
            keywords = {Quantum Foundations},
            language = {en},
            title = {Local states and channels in causal theories},
            publisher = {Perimeter Institute for Theoretical Physics},
            year = {2011},
            month = {may},
            note = {PIRSA:11050058 see, \url{https://scivideos.org/pirsa/11050058}}
          }
          

Abstract

We will analyze different aspects of locality in causal operational probabilistic theories. We will first discuss the notion of local state and local objective information in operational probabilistic theories, and define an operational notion of discord that coincides with quantum discord in the case of quantum theory. Using such notion, we will show that the only theory in which all separable states have null discord is the classical one. We will then analyze locality of transformations, reviewing some general properties of no-signaling channels in causal theories. We will show that it is natural to define transformations on no-signaling channels that cannot be extended to all bipartite channels, and discuss the consequences of this fact on information processing.