AIP conference proceedings
From Quantum Interference to Bayesian Coherence and Back Round Again
Christopher A. Fuchs, Rüdiger Schack, Luigi Accardi, Guillaume Adenier, Christopher A. Fuchs, Gregg S. Jaeger, Andrei Yu. Khrennikov, Jan-Åke Larsson, Stig Stenholm
Abstract
In the quantum Bayesian understanding of quantum states being developed by the authors and collaborators, the Born Rule cannot be interpreted as a rule for setting measurement‐outcome probabilities from an objective quantum state. But if not, what is the role of the rule? In this paper, we argue that it should be seen as an empirical addition to Bayesian reasoning itself. Particularly, we show how to view the Born Rule as a normative rule beyond Dutch‐book coherence, which takes into account how one should assign probabilities to the consequences of various intended interactions with a physical system, but explicitly in terms of prior probabilities for and conditional probabilities consequent upon the imagined outcomes of a special counterfactual reference interaction. This interpretation is seen particularly clearly by representing quantum states in terms of probabilities for the outcomes of a fixed, fiducial symmetric informationally complete (SIC) measurement. We further explore the extent to which the general form of the new normative rule implies the full state space structure of quantum mechanics.