Quantum teleportation demonstrated for the fist time

Discussion in 'Physics & Math' started by Plazma Inferno!, Sep 20, 2016.

  1. Plazma Inferno! Ding Ding Ding Ding Administrator

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    Two separate teams of scientists have taken quantum teleportation from the lab into the real world.
    Researchers working in Calgary, Canada and Hefei, China, used existing fiber optics networks to transmit small units of information across cities via quantum entanglement.
    According to quantum mechanics, some objects, like photons or electrons, can be entangled. This means that no matter how far apart they are, what happens to one will affect the other instantaneously.
    A few experiments in the lab had previously managed to send information using quantum entanglement But translating their efforts to the real world, where any number of factors could confound the process is a much more difficult challenge. That’s exactly what these two teams of researchers have done. Their breakthrough, published in two separate papers today in Nature Photonics, promises to offer important advancements for communications and encryption technologies.

    http://blogs.discovermagazine.com/d-brief/2016/09/19/quantum-teleportation-enters-real-world/

    I've omitted sensationalism from the article. Some parts are incorrect like that scientists used entanglement to transmit the information, while in fact they used it for decryption. They transmitted information via photons (at speed of light).
    Also, links to scientific papers are incorrect.
    Here are the first and the second.
    Still, this is a great achievement.
     
    danshawen likes this.
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  3. Sarkus Hippomonstrosesquippedalo phobe Valued Senior Member

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    Yeah, it does smack of "instant communication" in the way it's written, but that's sensationalist journalism for you.
    Also, it says that in one experiment they could guess the state of the photons 25% or at most 50% of the time? I'm assuming, therefore, that the photon states weren't simply binary, as 50% would suggest no better than random, and 25% is decidedly worse, and suggests that they simply need to guess the other way round than that predicted!

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    So how many different states were they using?
     
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  5. Dinosaur Rational Skeptic Valued Senior Member

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    From Plazma Inferno Post #1
    The above notion seems to be due to a journalist misunderstanding a remark by a physist he interviewed.

    Many (most/all?) Properties of entangled particles are analogous to the following.
    For the above situation, you would not claim that knowledge of the gender of the arriving spouse affected the gender of the distant spouse.
     
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  7. danshawen Valued Senior Member

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    Makes sense. Even if information 'decryption' uses entanglement, a stream of entangled particles must exist that have been entangled at the beginning of their propagation.

    Encryption too is information, but don't take my word for it. Claude Shannon had rather a lot to say on the subject, a large chunk of which was the subject of my successful technical career. Encryption itself is a form of entanglement, roughly equivalent to retransmission of an entire stream of data in the form of a shorter (and also more efficient) unique code word. Fascinating. I can understand now how quantum computing is a natural application of this technology.

    Any sort of information, even a single bit, is layered, as is entanglement. That a bit exists or not is only the top layer 'propagation'. That it is entangled with another bit is a deeper information layer. Notice how intimate a role time itself (and not the nominal speed of linear propagation) plays in this process. No more theoretical limits to channel bandwidths between any two points, however distant, is just the beginning.
     
    Last edited: Oct 20, 2016
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