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 rho AB , we always have 0 <= N(rho AB ) < 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.