Researchers from Nanjing University in China have used drones to transmit photons — light particles — across a kilometer of air and have found they can keep the particles quantum-entangled through this journey. 

Let me try and break this down. If you generate a pair of particles together, they have to balance out a lot of different characteristics like a matched yin and yang of particle physics. If one of the balanced characteristics in one of the entangled particles changes, somehow the other particle will instantly change to keep things in balance. How this “spooky action at a distance” works is not understood but understood or not, folks would like to take advantage of this property to allow instantaneous communications across long distances.

In this particular experiment, equipment on one drone generated two particles and transmitted one of the particles to another drone and the other particle to a ground station, which then relayed that particle to another ground station. Through all of this, the particles stayed entangled. 

This work is described in the journal Physical Review Letters, and it raises the possibility of drone-enabled quantum networks becoming a real thing someday in the future. Considering how loud drones can be and how much of a hazard they can be for airplanes, I’m not sure if this is something I want to see become our reality, but if Amazon can someday deliver packages with drones, we can also use them to set up particle relay stations.

Whatever happens, the future will be weird and awesome and require a lot of quantum mechanics.

More Information

Science News article

“Optical-Relayed Entanglement Distribution Using Drones as Mobile Nodes,” Hua-Ying Lui et al., 2021 January 15, Physical Review Letters