Nonclassicality by Local Gaussian Unitary Operations for Gaussian States

A measure of nonclassicality N in terms of local Gaussian unitary operations for bipartite Gaussian states is introduced. N is a faithful quantum correlation measure for Gaussian states as product states have no such correlation and every non product Gaussian state contains it. For any bipartite Gaussian state ρAB, we always have 0≤N(ρAB)<1, where the upper bound 1 is sharp. An explicit formula of N for (1+1)-mode Gaussian states and an estimate of N for (n+m)-mode Gaussian states are presented. A criterion of entanglement is established in terms of this correlation. The quantum correlation N is also compared with entanglement, Gaussian discord and Gaussian geometric discord.

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