In ground tests this year, Boeing engineers got two separately created pairs of entangled photons to hand their entanglement to two photons that had never met, all on a 15-kilogram payload, and the open question now is whether that fragile trick survives the handful of watts and violent thermal swings of orbit

Take two pairs of entangled photons that were generated separately and never interacted. Perform a single joint measurement on one photon from each pair, and the two leftover photons — strangers until that instant — come out entangled with each other. Boeing has now pulled off that maneuver, called entanglement swapping, on a compact payload [...] The post In ground tests this year, Boeing engineers got two separately created pairs of entangled photons to hand their entanglement to two photons t