Quantifying tripartite spatial and energy-time entanglement in nonlinear optics
James Schneeloch, Richard J. Birrittella, Christopher C. Tison, Gregory A. Howland, Michael L. Fanto, Paul M. Alsing · Physical Review Research · 2022
In this work, we provide a means to quantify genuine tripartite entanglement in arbitrary (pure and mixed) continuous-variable states as measured by the tripartite entanglement of formation---a resource-based measure quantifying genuine multipartite entanglement in units of elementary Greenberger-Horne-Zeilinger (GHZ) states called gebits. Furthermore, we predict its effectiveness in quantifying the tripartite spatial and energy-time entanglement in photon triplets generated in cascaded spontaneous parametric down-conversion (SPDC), and find that ordinary nonlinear optics can be a substantial resource of tripartite entanglement.