• rebelsimile@sh.itjust.works
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    2 months ago

    could a record like this be used as a presence detector? Like if there was any observer who collapsed the wave function then we’d get the collapsed lines in the log, otherwise it would have indicated no observers? (obviously even what the hell is an ‘observer’ anyway?)

        • cynar@lemmy.world
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          2 months ago

          We can observe the end result. E.g. observing the screen only, and you get wavelike behaviour. When you also observe the slit, the wavelike behaviour disappears, and it seems particle like.

          Both end in an observation, 1 has an extra observation.

            • cynar@lemmy.world
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              2 months ago

              You could detect decoherence in the system, that doesn’t indicate a human observer, however.

              That process is, however, used to protect cryptographic keys, transfered between banks. A hostile observer collapses the state early. The observer gets the key instead of the 2nd bank, which is extremely conspicuous to both banks.

        • ulterno@lemmy.kde.social
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          2 months ago

          It is “guessed” using whatever mathematical model that matches the system.

          Of course, if our whole theory is wrong, then the guess will be wrong and we won’t know unless some condition arises where the predicted result and the observed result are different.

    • cynar@lemmy.world
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      2 months ago

      Observer here doesn’t mean the same as the layman meaning. It’s anything that interacts with the system while it’s developing.

      Interestingly, it actually can be used for a presence detector, at least in a sense. You can use it to transfer cryptographic information. If no-one is listening in, about half your sent numbers are wrong, but you can agree on what ones. However, if someone is listening in, all your data gets randomised.

      They actually now use this system to transfer information between banks. They send a random stream of 0s and 1s over a fibre optic cable. They then send (semi publicly) which bits made it properly. If someone spliced into the fibre, they would get the encryption data, but the target bank would not! They know instantly that something is wrong.

    • Justin@lemmy.jlh.name
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      2 months ago

      Yes. This is how motion detectors work. Normally, motion detectors have an IR emitter that acts as a particle, but when someone walks by, the IR emitter works as a wave, triggering the motion detector.

      Notably, this doesn’t work with dogs, as they have no souls.

      • pumpkinseedoil@mander.xyz
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        2 months ago

        Notably, this doesn’t work with dogs, as they have no souls.

        Which kind of motion detectors? The ones I know work on everything that’s moving, including my cats (don’t have dogs) or even just throwing something past it

        • Justin@lemmy.jlh.name
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          2 months ago

          Oh, you might have one of the newer ones that use interferometry to detect soulless entities.