Confined contextuality: How specific counterfactual paradoxes in pre- and post-selected Kochen-Specker sets give rise to experimentally observable consequences.

          @misc{ scivideos_PIRSA:16060039,
            doi = {10.48660/16060039},
            url = {https://pirsa.org/16060039},
            author = {},
            keywords = {Quantum Foundations},
            language = {en},
            title = {Confined contextuality:  How specific counterfactual paradoxes in pre- and post-selected Kochen-Specker sets give rise to experimentally observable consequences.},
            publisher = {Perimeter Institute for Theoretical Physics},
            year = {2016},
            month = {jun},
            note = {PIRSA:16060039 see, \url{https://scivideos.org/index.php/pirsa/16060039}}
          }
          

Abstract

The Kochen-Specker (KS) theorem can gives rise to logical paradoxes under pre- and post-selection in which the contextual behavior is confined to specific observables of a system. Weak measurements allow direct experimental observation of the nonclassical behavior of these specific observables. This presents an experimental advantage over other tests of KS inequalities which rule out a particular class of counterfactual noncontextual hidden variable models, but can never specify where the contradiction occurs, nor make any direct observation of its consequences. The confined contextuality can always be interpreted as a logical pre- and post-selection paradox, such as the 3-box paradox, the Quantum Cheshire Cat, or the Quantum Pigeonhole Effect. This confined contextuality was recently observed using neutron inferometry for KS sets of up to 17 qubits. Details of the theory and experimental results will be presented.