Comment on Gottem

• Cethin@lemmy.zip ⁨1⁩ ⁨day⁩ ago

  Yes, that’s correct! Interacting with the barrier that creates the splits we don’t care about, but yes, that collapses it too.

  Interacting with the surface we’re measuring in all the experiments. It doesn’t change, so it shouldn’t be effecting the results. It does collapse the waveform though, which is how we measure it.

  Detecting it at the slit is the part that changes. If we don’t do this, we get wave-like behavior, because there’s no interaction until it hits the surface at the end. The wave can pass through both slits without any interaction. If we put in a detector, then it must interact with that to pass through, so it collapses the waveform and behaves like a particle at that point. This means it must be at one slit or the other, and not both.

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  • Smoogs@lemmy.world ⁨21⁩ ⁨hours⁩ ago

    And What are the ‘detectors’ that were used?

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  • vivalapivo@lemmy.today ⁨1⁩ ⁨day⁩ ago

    Interacting with the barrier that creates the slits we don’t care about, but yes, that collapses it too.

    Ok, I see you’re ignorant actually. Interactions do not lead to the collapse, they are intrinsic part of quantum fields. Collapse happens when you step out of quantum picture with (mostly)linear equations and try to project the calculations onto the “classical picture”, whatever your cult of choice explains how that’s actually happening.

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    • Cethin@lemmy.zip ⁨1⁩ ⁨day⁩ ago

      Yeah… no. There are multiple interpretations, but basically it’s when position is needed to be known that causes it. Until then, the position is in a superstate of all possible positions, but for an interaction to occur it needs to be in one position. It’s not about choice. It’s about when information is needed for a physical interaction to occur. If one occurs then the particle must be at that location.

      Collapse happens when you step out of quantum picture with (mostly)linear equations and try to project the calculations onto the “classical picture”

      This (at least your wording) implies that physics cares about our mathematical models. It doesn’t. Quantum mechanics and “classical” physics are just ways we organize things for education. Though we don’t have a model for it, the unvirse is not using two separate models of physics. There is no “quantum mechanics” and “classical physics”. There is only physics. When a measurement occurs the universe isn’t looking at it to see if it should use quantum rules or classical rules. The interaction just occurs.

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      • bunchberry@lemmy.world ⁨1⁩ ⁨day⁩ ago

        You cannot defend value indefiniteness. It is just solipsism. If particles do not have values when you are not looking, then any object made of particles also do not have values when you are not looking. This was the point of Schrodinger’s “cat” thought experiment. This view of “value indefiniteness” you are trying to defend is indefensible because it is literally solipsism and any attempt to promote it above solipsism will just become incoherent.

        You say:

        it’s when position is needed to be known that causes it. Until then, the position is in a superstate of all possible positions, but for an interaction to occur it needs to be in one position.

        This is trivially false, because then it would not be possible for two particles to become entangled on the position basis, which requires them to interact in such a way that depends upon their position values. The other particle would thus need to “know” its position value to become entangled with it, and if this leads to a “collapse,” then such entanglement could not occur. Yet we know it can occur in experiments.

        If by “know” you mean humans knowing and not other particles, yeah, okay, but that’s obviously solipsism.

        Any attempt to defend value indefiniteness will always either amount to:

        1. Solipsism
        2. Something that is trivially wrong
        3. A theory which is not quantum mechanics (makes different predictions)

        This (at least your wording) implies that physics cares about our mathematical models. It doesn’t. Quantum mechanics and “classical” physics are just ways we organize things for education.

        I don’t blame them, it is literally the textbook Dirac-von Neumann axioms. That is how it is taught in schools, even though it is obviously incoherent. You are taught that there is a “Heisenberg cut” between the quantum and classical world, with no explanation of how this occurs.

        Though we don’t have a model for it, the unvirse is not using two separate models of physics. There is no “quantum mechanics” and “classical physics”. There is only physics.

        The problem is that the orthodox interpretation of quantum mechanics does not even allow you to derive classical physics minus gravity in a limiting case from quantum mechanics. It is not even a physical theory of nature at all.

        We know from the macroscopic world that particles have real observable properties, yet value indefiniteness denies that they have real observable properties, and it provides no method of telling you when those real, observable properties are added back to the world. It thus cannot make a single empirical prediction at all without this slight-of-hand where they just say, as a matter of axiom in the Dirac-von Neumann textbook axioms of quantum mechanics that it happens “at measurement.”

        If measurement is taken to be a subjective observation, then it is just solipsism. If measurement is taken to be a physical process, then it cannot reproduce the mathematical predictions of quantum mechanics, because this “Heisenberg cut” would be a non-reversible process, yet all unitary evolution operators are reversible. Hence, any model which includes a rigorous definition of “measurement” (like Ghirardi–Rimini–Weber theory) would include an additional non-reversible process. You could then just imagine setting up an experiment where this process would occur and then try to reverse it. The mathematics of quantum mechanics and your theory would inevitably lead to different predictions in such a process.

        Therefore, again, if you believe in value indefiniteness, then you either (1) are a solipsist, (2) don’t believe in quantum mechanics but think it will be replaced by a physical collapse model, or (3) are confused.

        The only way for quantum mechanics to be self-consistent is to reject value indefiniteness, at least as a metaphysical point of view. This does not require actually modifying the mathematics. If nature is random, then of course the definite values will evolve statistically such that they could not be tracked and included in the model. All you would need to then demonstrate is that quantum statistics converges to classical statistics in a limiting case on macroscopic scales, which is achieved by the theory of decoherence.

        But the theory of decoherence achieves nothing if you believe in value indefiniteness, because if you believe quantum mechanics has nothing to do with statistics at all, then there is no reason to conclude that what you get in the reduced density matrices after you trace out the environment has anything to do with classical statistics, either.

        There is no good argument in the academic literature for value indefiniteness. It is an incoherent worldview based on no empirical evidence at all. People who believe it often just regurgitate mindlessly statements like “Bell’s theorem proves it!” yet cannot articulate what Bell’s theorem even is or how on earth is proves that, especially since Bell himself was the biggest critic of value indefiniteness yet wrote the damned theorem!

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