The experiment demonstrated the distribution of three entangled particles, which can eventually be used to do more than pairwise communication where only one party can communicate with another. It opens the possibility for multipartite quantum communication protocols, including Quantum Key Distribution (QKD), third man cryptography and quantum secret sharing.
“The interesting result is that we now have the ability to do more than paired quantum communication,” said the paper’s lead author Chris Erven, a former IQC PhD student who is now a research assistant at the University of Bristol. “QKD, so far, has been a pairwise system – meaning that it works best and with less assumptions when you’re only talking with one other person. This is the first experiment where you can now imagine a network of people connected in different ways using the correlations between three or more photons.”