When China announced the launch of its quantum satellite (the Quantum Experiments at Space Scale, or QUESS) for July, I was excited, but attempts to express my excitement to others was met with bored glances and angry cries of “NEEEERRRRRD!” The world we live in is a sexy sci-fi bordello of wonders, so we’re all going to sit down and learn why quantum communication is 1) necessary, 2) basically magic.
China is the biggest name in quantum communication at the moment for a very specific reason: it’s hack-proof. Also, it works via magical sunbeams. Parties share a message—via, say, polarized photons—and by virtue of the rules of quantum mechanics, anyone who tries to intercept that message receives gobbledygook and the parties are aware of it. When you measure a photon, you change its quantum state, so anyone trying to listen in will corrupt the message. Also, magical sunbeams.
The 500 kilogram satellite China will be putting in the air will link with two ground stations, one in China one in Europe, when it’s flitting around outer space (going so fast that it only takes 90 minutes to orbit the earth), 1,000 kilometers up (or down, or left—directions in space are weird). With the China Academy of Sciences at the helm the satellite will contain a “quantum key communicator, quantum entanglement emitter, entanglement source, processing unit, and a laser communicator.” If you just heard static in your head, don’t worry, it’s much more complicated than it sounds.
The big brain behind the QUESS is Pan Jian-Wei of the University of Science and Technology of China in Hefei simplified the process in an interview with Nature: “We will beam one photon from an entangled pair created at a ground station in Ali, Tibet, to the satellite. The quantum state of a third photon in Ali can then be teleported to the particle in space, using the entangled photon in Ali as a conduit.”
Now that we’ve established that it’s basically wizardry, we also need to talk about how quantum communication is important. It’s fast. Really fast. Think, speed of light, then speed it up. In fact, it kind of is light. But, this highly expensive, unbelievably complicated form of contact couldn’t be the future of mass communication, could it? Wrong! You are wrong, rhetorical question. China’s already built a 2,000 kilometer long network between Beijing and Shanghai, and the hope is to connect this ground system to the one China is putting into space. And a report from the South China Morning Post claims that the system could be expanded worldwide by 2030.
As one might imagine, China isn’t the only place interested in this form of communication, with Japan, Canada, and the US all involved in similar projects, with a currently unfunded US plan for a 10,000 kilometer plan linking major cities. Quantum entanglement works at any distance and at speeds that are hard to imagine; it’s hard to see how (if all goes well) this isn’t the (very) far future of mass communication.
Even more importantly, this sort of work shows a quantum shift (nailed it) in China’s science ambitions. This type of experiment is what’s known as a basic-science space mission—not that it’s basic in the sense of being usual, rather that it’s testing and trying out basic concepts. Pan Jian-Wei’s project for hack-proof, speed-of-light communications had a little something to do with this shift in focus. “My colleagues at the Chinese Academy of Sciences (CAS) and I helped to force things in this direction. In the past, China had only two organizations that could launch satellites: the army and the Ministry of Industry and Information Technology. So scientists had no way to launch a satellite for scientific research.”
This new quantum satellite isn’t even the only basic science mission China has running at the moment. QUESS will be happy to know DAMPE, the Dark Matter Particle Explorer looking for dark matter in near space, is also knocking about up there.
Now, quantum states are a pretty confusing thing, so if you’re sitting there wondering why they work, you’re going to be sitting for quite some time. The truth is that this is a cutting edge of applicable science and China is on breakaway end of the spectrum in this respect.
Cover image from CCTV