Photonic families of non-Gaussian entangled states and entanglement criteria for continuous-variable systems
Ryo Namiki · Physical Review A · 2012
We consider two classes of non-Gaussian entangled states generated from the product of number states by the action of the beam splitter or the two-mode squeezer. It is shown that, for many of these states, the covariance matrix is compatible with the covariance matrix of separable Gaussian states and their separability cannot be verified by the measurements of the first and second moments of canonical variables. We identify a couple of continuous-variable entanglement criteria with higher-order moments to verify these non-Gaussian entanglements.