Quantum Physics Commons^™

A Bayesian Approach To Compatibility, Improvement, And Pooling Of Quantum States, Matthew S. Leifer, Robert W. Spekkens

Mathematics, Physics, and Computer Science Faculty Articles and Research

In approaches to quantum theory in which the quantum state is regarded as a representation of knowledge, information, or belief, two agents can assign different states to the same quantum system. This raises two questions: when are such state assignments compatible? and how should the state assignments of different agents be reconciled? In this paper, we address these questions from the perspective of the recently developed conditional states formalism for quantum theory [1]. Specifically, we derive a compatibility criterion proposed by Brun, Finkelstein and Mermin from the requirement that, upon acquiring data, agents should update their states using a quantum …