42 research outputs found
Practically state-independent test of contextuality with 9 observables
We propose a test of quantum contextuality for a single three-level system
that uses nine projective measurements. It has a form of an inequality that has
to be satisfied by any non-contextual theory and which is violated by any
quantum state, except for the maximally mixed one. Due to the fact that there
is only a single state that does not exhibit contextuality, it is natural to
ask what the difference between state-independent tests and the one proposed
here is.Comment: 3 pages, 1 figur
Entropic tests of multipartite nonlocality and state-independent contextuality
We introduce a multipartite extension of an information-theoretic distance
first introduced in [Nature 341, 119 (1989)]. We use this new distance to
derive entropic tests of multipartite nonlocality for three and for an
arbitrary even number of qubits as well as a test of state-independent
contextuality. In addition, we re-derive the tripartite Mermin inequality and a
state-independent non-contextuality inequality by Cabello [Phys. Rev. Lett.
101, 210401 (2008)]. This suggests that the information-theoretic distance
approach to multipartite nonlocality and state-independent contextuality can
provide a more general treatment of nonclassical correlations than the orthodox
approach based on correlation functions.Comment: 5 pages, 3 figures, extended version of arXiv:1409.7290 with more
general result