Non-Gaussian nature and entanglement of spontaneous parametric nondegenerate triple-photon generation

摘要: 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, degree of entanglement between modes stronger than corresponding to two-mode squeezed vacuum produced quadratic Hamiltonian with same parameters. Furthermore, we propose model prepare sub-Gaussian entangled states tunable negative Wigner function based on quadrature projection measurements. find these Gaussian measurements outcomes $X\ensuremath{\ge}1$ not only improve residual two but also introduce component, resulting in coexistence and entanglement.