The Chinese proved last month that, quantum communication is possible between Earth and space, so what did they do? They used the technology to send a photon to space, using quantum teleportation. Yes you read well, quantum teleportation.
Micius (the Chinese quantum satellite) was the spearhead in space which was used to conduct the experiment from a ground station. Researchers were able to transfer the unknown quantum state from one photon here on Earth to another one in space.
Don’t confuse this for the teleportation showed in Star Trek. If you want to teleport something on a quantum scale, everything is not as glamorous as it was over there. To teleport all the properties of a particle – its quantum state – some drastic measures are required.
First of all, it’s not at all possible to know a quantum state perfectly, and that is why it’s not possible to copy it. But, if you decide to destroy the particle, you can easily transfer the quantum state on another particle. You will get an exact equivalent of the old particle.
Quantum teleportation is a crucial requirement to create a quantum Internet that allows quantum computers to communicate between themselves. The overuse of the word quantum in the previous sentence is not to make it sound complex. Quantum computers are computers that can use the laws of quantum mechanics to perform calculations faster than even the best supercomputer we can build – and at a fraction of the size.
A lot of things need to be resolved before we can make quantum computers viable, but, this goes a long way in helping us understand and establishing long-distance communication. The satellite was 1,400 kilometers (870 miles) away from the ground station.
“Long-distance teleportation has been recognized as a fundamental element in protocols such as large-scale quantum networks and distributed quantum computation,” the research team wrote in the paper, which is yet to be peer-reviewed. “However, the 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.”
The principle of entanglement is used in quantum teleportation (two particles can influence each other instantaneously no matter the distance). This might at first seems a violation of special relativity since information cannot travel at the speed of light, but it isn’t. If you have entangled particles, their quantum state is shared. It doesn’t make sense (at least in quantum mechanics) to consider them as single entities.
There are a lot of benefits from entanglement. But, we have to mention that it’s also fragile, meaning that, you can basically “break” the quantum state very easily and what will happen is that both of the particles will be individual afterwards. And that’s why so far it has been difficult to send these quantum states for more than 100 km over fiber optics or air.
At least one thing was shown from the research. to create a truly global network for quantum communication, we will need quantum satellites.
Original article here.