PIRSA:08020052

Measurement ordering contextuality and the search for psi-epistemic theories

Westman, H. (2008). Measurement ordering contextuality and the search for psi-epistemic theories. Perimeter Institute. https://pirsa.org/08020052

Westman, Hans. Measurement ordering contextuality and the search for psi-epistemic theories. Perimeter Institute, Feb. 26, 2008, https://pirsa.org/08020052 

          @misc{ pirsa_PIRSA:08020052,
            doi = {10.48660/08020052},
            url = {https://pirsa.org/08020052},
            author = {Westman, Hans},
            keywords = {Quantum Foundations},
            language = {en},
            title = {Measurement ordering contextuality and the search for psi-epistemic theories},
            publisher = {Perimeter Institute},
            year = {2008},
            month = {feb},
            note = {PIRSA:08020052 see, \url{https://pirsa.org}}
          }

Hans Westman

Talk number
PIRSA:08020052
Collection
Talk Type
Subject
Abstract
We prove that all non-conspiratorial/retro-causal hidden variable theories has to be measurement ordering contextual, i.e. there exists *commuting* operator pair (A,B) and a hidden state \\\\lambda such that the outcome of A depends on whether we measure B before or after. Interestingly this rules out a recent proposal for a psi-epistemic due to Barrett, Hardy, and Spekkens. We also show that the model was in fact partly discovered already by vanFraassen 1973; the only thing missing was giving a probability distribution on the space of ontic states (the hidden variables).