Continuous variable quantum conference network with a Greenberger–Horne–Zeilinger entangled state

Abstract

Quantum conference (QC) is a cryptographic task in secure communications that involves more than two users wishing to establish identical secret keys among N users. The Greenberger–Horne–Zeilinger (GHZ) entangled state is the basic resource for quantum cryptographic communication due to the existence of multipartite quantum correlations. An unconditional and efficient quantum network can be established with a continuous variable (CV) GHZ entangled state because of its deterministic entanglement. Here, we report an implementation of QC scheme using a CV multipartite GHZ entangled state. The submodes of a quadripartite GHZ entangled state are distributed to four spatially separated users. The proposed QC scheme is proved to be secure even when the entanglement is distributed through lossy quantum channels and the collective Gaussian attacks are in the all lossy channels. The presented QC scheme has the capability to be directly extended to a larger scale quantum network by using entangled states with more submodes.

Entanglement Generation of Polar Molecules via Deep Reinforcement Learning

“…Multipartite entanglement is a significant resource in QIP, exhibiting more peculiar physical properties and stronger nonclassical correlations than the entanglement in bipartite systems . Here, we concentrate on the generation of the tripartite GHZ state and W state using three dipole–dipole-coupled CaF molecules, where true| G H Z false⟩ = 1 2 ( false| 000 ⟩ + false| 111 false⟩ ) and | W ⟩ = 1 3 ( false| 001 ⟩ + false| 010 ⟩ + false| 100 false⟩ ) .…”