English

"Haunted" quantum contextuality

Quantum Physics 2007-05-23 v2

Abstract

Two entangled particles in threedimensional Hilbert space (per particle) are considered in an EPR-type arrangement. On each side the Kochen-Specker observables {J12,J22,J32}\{J_1^2,J_2^2,J_3^2\} and {Jˉ12,Jˉ22,J32}\{\bar J_1^2, \bar J_2^2,J_3^2\} with [J12,Jˉ12]0[J_1^2,\bar J_1^2]\neq 0 are measured. The outcomes of measurements of J32J_3^2 (via J12,J22J_1^2,J_2^2) and J32J_3^2 (via Jˉ12,Jˉ22\bar J_1^2,\bar J_2^2) are compared. Although formally J32J_3^2 is associated with the same projection operator, a strong form of quantum contextuality states that an outcome depends on the complete disposition of the measurement apparatus, in particular whether J12J_1^2 or Jˉ12\bar J_1^2 is measured alongside. It is argued that in this case it is impossible to measure contextuality directly, a necessary condition being a non-operational counterfactuality of the argument.

Keywords

Cite

@article{arxiv.quant-ph/9907015,
  title  = {"Haunted" quantum contextuality},
  author = {Karl Svozil},
  journal= {arXiv preprint arXiv:quant-ph/9907015},
  year   = {2007}
}