It can look dumb, but I always had this question as a kid, what physical principles would prevent this?

  • WorldsDumbestMan@lemmy.today
    link
    fedilink
    arrow-up
    3
    arrow-down
    2
    ·
    19 days ago

    Nah, I prefer using quantum spookiness for that. Send a steady stream of entangled particles to the other person on the moon first. Any time you do something to the particles on Earth, the ones on the Moon are affected also. The catch is that this disentangles them, so you have only a few limited uses. This is why you want a constant stream of them being entangled.

    • pcalau12i@lemmygrad.ml
      link
      fedilink
      English
      arrow-up
      2
      ·
      21 hours ago

      Any time you do something to the particles on Earth, the ones on the Moon are affected also

      The no-communication theorem already proves that manipulating one particle in an entangled pair has no impact at al on another. The proof uses the reduced density matrices of the particles which capture both their probabilities of showing up in a particular state as well as their coherence terms which capture their ability to exhibit interference effects. No change you can make to one particle in an entangled pair can possibly lead to an alteration of the reduced density matrix of the other particle.

    • InputZero@lemmy.world
      link
      fedilink
      arrow-up
      2
      ·
      19 days ago

      This wouldn’t work, entangled particles don’t work like that. They would be disentangled the moment you do anything to either particle of the entangled pair. The only time any information can be encoded onto entangled particles is when they’re created.

      • ulterno@programming.dev
        link
        fedilink
        English
        arrow-up
        2
        ·
        edit-2
        19 days ago

        The only time any information can be encoded onto entangled particles is when they’re created.

        If that were the case, then we aren’t really doing FTL communication, unless we manage to entangle them at a distance. No?

        OIC, it’s still useful if we want to make a secret key and send it somewhere. Then both sides can take a reading sometime in the future and they can then use whatever cluster of entangled particles they saw, as the symmetric key.

    • ameancow@lemmy.world
      link
      fedilink
      English
      arrow-up
      2
      arrow-down
      1
      ·
      edit-2
      19 days ago

      You also cannot choose the spins of entangled particles, they collapse randomly in either direction when interacted with, meaning you cannot send messages. If you can figure out how to directly influence the spin of generated subatomic particles then BAM you have FTL communication.

      But you would be amazed how many obstacles the universe throws in front of you when you try to break the speed of causality. Faster than light communication isn’t possible because it makes no sense when you understand it. It’s like “getting answers faster than questions.” It’s nonsense.

      • JackbyDev@programming.dev
        link
        fedilink
        English
        arrow-up
        1
        ·
        19 days ago

        Wouldn’t that still be normal light speed communication from earth to two places on the moon, not FTL communication between two places on the moon?