Monday, May 21, 2012

Scientists teleport data over a distance of 100 km

Teleportation is something that belongs to the realm of science fiction, but scientists have brought it one step closer to reality. Using principles of quantum mechanics, they managed to teleport data from one place to another over a distance of 97 km. This process is instantaneous, and even though it will not allow us to actually send massive objects such as ourselves through space and time, it will help us by creating quantum networks for exchange of data.

Quantum entanglement

Teleporting stuff is only possible using entangled particles. Quantum entanglement is a peculiar feature of nature that binds two particles together. As a result, they will have the exact opposite properties. However, because of something called superposition, particles exist in all possible theoretical states until they are measured. To simplify this: if a particle can attain the value 0 or 1, it is both 0 and 1, and everything in between when it is in a state of superposition. Peculiar enough, if we measure the particle, it assumes the identity of either 0 or 1, and the second particle in the entangled pair will automatically and directly assume the opposite identity.
A graphical interpretation of quantum entanglement. 
An entangled system of two particles can be decoupled, after which both particles are sent away from each other. In a study performed by Chinese researchers, they managed to beam two entangled photons, the particles of light, almost 100km away from each other. Another peculiar fact about quantum entanglement is that once two entangled particles have been detached from each other, they still assume opposite identities. That means, once one of the particles is measured, the other one immediately assumes the opposite identity, no matter how far away the second particle is: even if it is on the other side of the universe. Because measurement at location A affects outcome at location B, this is basically teleportation of data.

Data exchange
While it will not allow us to teleport actual matter, we are able to instantly transfer data between two points. Entangled photons can serve as qubits, the quantum equivalent of bits used as units of information in conventional computers. Qubits can use properties of particles, such as the spin, as units of information. Let's say a particle can spin left or right: in superposition, it would spin both left and right and everything in between, until scientists want to measure either left or right. This could be equivalents for the 0 and 1 values that traditional bits attain. A series of qubits and the use of spin characteristics can therefore provide the basis of a quantum computer.

The Chinese researchers used quantum entangled photons and put them 97 km apart. Using the principles of quantum teleportation, they managed to 'send' the quantum states of about five photons per minute from one side to the other. This is the equivalent of teleporting five qubits per minute, which is not a lot of information, regardless of the fact that each qubit, due to superposition, can hold way more information than an ordinary computer bit. Nevertheless, instantly teleporting data almost 100 km away is a pretty neat trick, as the previous teleportation record was a mere 16 km.

Scientists hope to use satellites to transport entangled photons even further away from each other. Eventually, that would make global teleportation possible, but the scientists would have to fix the transfer speed of individual quantum states first. Sending around five photon properties per minute is by far not enough to provide us with the speedy communication that quantum computing promises. But the proof-of-principle is a step in the right direction.


  1. You fundamentally do not understand the nature of Quantum Entanglement, and the article you site isn't even talking about Faster than Light communication, simply encryption.

  2. I do not believe I mentioned faster than light communication, and I don't think it is relevant here. And if you believe I explained something wrongly, then please be so kind as to point out where the mistake is. :-)

  3. "Scientists teleport data over a distance of 100 km"

    An honest title would be "Scientists maintain quantum entanglement over 100 km"

    Your title isn't even *technically* correct. If you can't be bothered to post something that isn't sensationalist in order to garner readership, I can't be bothered to read your interpretation.

  4. You:
    "While it will not allow us to teleport actual matter, we are able to instantly transfer data between two points."

    From the Article you site:
    "When a photon is changed at A, the particle at B also changes. No information passes from A to B, but the photon change can be used to partially encode quantum bits, called qubits. Rather like a letter that can't be opened, these can only be reconstructed at B using additional data communicated conventionally from point A, so information is not being sent faster than light."

  5. While perhaps less accurate, I do not see why the title is wrong. Do know this is not a scientific journal. I am merely translating the findings and I believe teleportation, with the right explanation, is a term that can be used.

    As for the point mentioned above. The data itself is transferred from point A to point B instantly, which in my opinion is the most awesome part. The interpretation of the data needs more time, yes. But I've also stated in the outlook that the practical implications of this form of transfer speed are far from 'instant'.

  6. Transferred implies transmission, nothing get's "transferred" at the point in time at which you examine the spin of your entangled photon, it simply takes on a characteristic that is guaranteed to be opposite to that of the other photon in the pair. It's like having two envelopes with different colored (let's say blue and red) cards inside: at entanglement each particle gets an envelope but you have no idea who got which one. When you open your particles envelope and see a red card you know the other particle's envelope has the blue card, but no "data" was transferred, its just an intrinsic property of the entangled system.