Quantum theory from rules on information acquisition

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The last decade has seen a wave of characterizations of quantum theory using the formalism of generalized probability theory.

In this talk, I will introduce a novel operational approach to characterizing and reconstructing quantum theory which puts an observer’s information acquisition -- rather than the probability structure – centre stage. In particular, we consider an observer interrogating a system with binary questions and explain how an elementary set of rules governing the observer’s acquisition of information about the system leads to qubit quantum theory. The derivation is constructive, elucidating, among other things, the origin of entanglement, monogamy and more generally the correlation structure. This approach also yields a new characterization of pure states in terms of ‘conserved informational charges’ which, in turn, define the unitary group.