Comment on Quantum teleportation demonstrated over existing fiber networks — Deutsche Telekom’s T‑Labs used commercially available Qunnect hardware for the demo, claims 90% average accuracy

• MatSeFi@lemmy.liebeleu.de ⁨8⁩ ⁨hours⁩ ago

  Nope, the actual information must still be transported via a classical no quantum (and trusted) channel so that both ends can match their statistics and thus deduce the crytographic keys from the qunatum signals. And thats it what its all about: key exchange

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  • HubertManne@piefed.social ⁨6⁩ ⁨hours⁩ ago

    thanks. I had forgotten about that I think mainly because I can’t wrap my mind around how it works like if its intercepted and used then it will confirm that its void and produce a new one or such.

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• mech@feddit.org ⁨8⁩ ⁨hours⁩ ago

  Yes. If you could transport information faster than the speed of light, it’s easy to find examples that break causality, where an observer sees a message arrive before he sees it being sent.

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  • ParlimentOfDoom@piefed.zip ⁨8⁩ ⁨hours⁩ ago

    It’s argue that that would be breaking our ability to properly interpret causality, not that causality itself breaks. Things still occur in the order they happen regardless of what order we see them happen from different perspectives.

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    • mech@feddit.org ⁨8⁩ ⁨hours⁩ ago

      No, not if the observer can see the message arrive first, and immediately send a faster than light signal to the sender that turns off their transmitter, preventing the sending of their message.

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      • ParlimentOfDoom@piefed.zip ⁨7⁩ ⁨hours⁩ ago

        If they see the message arrive, it has already been sent (and received). Not seeing it get sent yet doesn’t mean it hasn’t happened yet. You’re not accounting for the frame of reference translation involved. Some of the information in your example has travel time. None of that information starts traveling before the things that created that information occurred, though.

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