Abstract
We theoretically demonstrate through numerical methods that the triple-photon state generated by three-photon spontaneous parametric down-conversion is a non-Gaussian Greenberger-Horne-Zeilinger state, showing super-Gaussian statistics. Interestingly, the degree of entanglement between the modes of the triple-photon state is stronger than that corresponding to the two-mode squeezed vacuum state produced by a quadratic Hamiltonian with the same parameters. Furthermore, we propose a model to prepare two-mode sub-Gaussian entangled states with a tunable negative Wigner function based on quadrature projection measurements. We find that these Gaussian projection measurements with outcomes not only improve the entanglement of the residual two modes but also introduce a Gaussian component, resulting in the coexistence of Gaussian and non-Gaussian entanglement.
- Received 25 April 2020
- Accepted 11 December 2020
DOI:https://doi.org/10.1103/PhysRevA.103.013704
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