Micius is the world’s first quantum communications, satellite launched by a Chinese research team from the Jiuquan Satellite Launch Centre in the Gobi Desert last year. The rocket, a Long March 2, placed Micius in a Sun-synchronous orbit so that it passes over the same point on Earth at the same time each day. Micius is a sensitive photon receiver that can detect the quantum states of single photons fired from the ground. That’s important because it should allow scientists to test the technological building blocks for various quantum feats such as entanglement, cryptography, and teleportation.
Now, the claim is that they’ve teleported the first object from the ground to orbit, and that’s where the reporting on this tends to go sideways.
China Did not Teleport an Object From Earth to Space (Quantum Teleportation Doesn’t Work That Way)
Quantum teleportation refers to the copying of information from one particle to another over great distances, via a process called quantum entanglement. In a nutshell, two particles form in the exact same position in space and at the exact same moment in time, and so share the same existence. Like most things having to do with quantum mechanics, this makes no intuitive sense.
However, after the particles are created, you can move one of them a create distance away, and whatever happens to one of them happens to the other, regardless of that distance. In the 1990’s, researchers realized they could use this link to transmit information from one point to another. The advantages were obvious – not only could information be transmitted over great distances instantaneously, it could be done with no way for an intermediary to intercept that information. In other words, it was an encryption scheme that would be absolutely unbreakable, the ultimate “security through obscurity” scheme.
What quantum teleportation really means, then, is to transmit everything about one particle to the other one. The second photon then takes on the identity of the first. To all intents and purposes, it becomes the first photon. What’s being transmitted is not the actual photon. That’s still impossible. Instead, you’re just creating dual reality particle out of two particles.
When you read “quantum teleportation”, you can substitute the phrase “copying information about a particle instantaneously over great distances to another particle”, and you’ll do just fine.
Buzzkill, you say? Perhaps. We’re science fiction geeks. This is the news page of the world’s longest-running and best established science fiction radio station. We do so love the idea of teleportation devices in our lifetime – but we are also journalists, and this is not Star Trek style teleportation. To post a headline that claims humans have achieved trans-orbital teleportation would be an abuse of trust.
Quantum Entangled Internet? Yes, Please.
Now that we’ve gotten the term confusion out of the way, quantum teleportation is one of the most important new technologies of our millennium so far. It’s a building block for a wide range of technologies, specifically in information networking.
It’s tricky stuff. In theory, there should be no maximum distance over which this can be done, but it’s also fragile. Photons interact with matter in the atmosphere or inside optical fibers, causing the entanglement to be lost. Because of this, actual working quantum teleportation is difficult to establish, let alone sustain.
As a result, the distance over which scientists have measured entanglement or performed teleportation is severely limited. “Previous teleportation experiments between distant locations were limited to a distance on the order of 100 kilometers, due to photon loss in optical fibers or terrestrial free-space channels,” says the team.
The reason the Micius satellite is important is that it orbits at an altitude of 500 kilometers, and for most of this distance, any photons making the journey travel through a vacuum. To get the cleanest possible signal, the Chinese team set up its ground station in Ngari in Tibet at an altitude of over 4,000 meters. The distance from the ground to the satellite varies from 1,400 kilometers when it’s near the horizon to 500 kilometers when it’s overhead.
“We report the first quantum teleportation of independent single-photon qubits from a ground observatory to a low Earth orbit satellite—through an up-link channel— with a distance up to 1400 km,” says the Chinese team. This is the first time that quantum entanglement has been established and proven over such a great distance.
That’s impressive work that sets the stage for much more ambitious goals in the future. “This work establishes the first ground-to-satellite up-link for faithful and ultra-long-distance quantum teleportation, an essential step toward global-scale quantum internet,” says the team.
It’s not what you think of as blindingly efficient when only 911 photons get quantum teleported out of about 2.5 million seconds during the month of the test. It is, however, proof of the concept that a quantum teleportation based internet is eventually possible.
Will the Chinese Hold This Secret For Themselves? No. They’re Sharing.
The information on how it was done and the science of it is in this paper (a PDF anyone with a background in the requisite mathematics can read).
That means it can be recreated and reproduced by others. It’s an impressive technological achievement, but they mean humanity to have it. It may be a long time before we can all reap the benefits of quantum teleportation as a way to move information around the internet, perhaps another decade. But we’ll get there.