On the Significance of the Quantum Mechanical Covariance Matrix
AbstractThe characterization of quantum correlations, being stronger than classical, yet weaker than those appearing in non-signaling models, still poses many riddles. In this work, we show that the extent of binary correlations in a general class of nonlocal theories can be characterized by the existence of a certain covariance matrix. The set of quantum realizable two-point correlators in the bipartite case then arises from a subtle restriction on the structure of this general covariance matrix. We also identify a class of theories whose covariance has neither a quantum nor an “almost quantum” origin, but which nevertheless produce the accessible two-point quantum mechanical correlators. Our approach leads to richer Bell-type inequalities in which the extent of nonlocality is intimately related to a non-additive entropic measure. In particular, it suggests that the Tsallis entropy with parameter
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Carmi, A.; Cohen, E. On the Significance of the Quantum Mechanical Covariance Matrix. Entropy 2018, 20, 500.
Carmi A, Cohen E. On the Significance of the Quantum Mechanical Covariance Matrix. Entropy. 2018; 20(7):500.Chicago/Turabian Style
Carmi, Avishy; Cohen, Eliahu. 2018. "On the Significance of the Quantum Mechanical Covariance Matrix." Entropy 20, no. 7: 500.
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