20 00 Covariance , Correlation and Entanglement
نویسندگان
چکیده
Some new identities for quantum variance and covariance involving commutators are presented, in which the density matrix and the operators are treated symmetrically. A measure of entanglement is proposed for bipartite systems, based upon covariance. This works for two-and three-component systems but produces ambiguities for multicomponent systems of composite diemnsion. Its relationship to angular momentum dispersion for symmetric spin states is described.
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