Recent content by charters

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    I What is the POVM generalization of Born's rule for quantum measurements?

    You are just misreading what I am saying. I am not talking about observed experimental outcomes or theory. Of course, rotating the SG changes the observed pattern, and of course rotating the SG measure a different Pauli operator in theory. The issue here is to what we *attribute* this...
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    I What is the POVM generalization of Born's rule for quantum measurements?

    I disagree. Placing a scale vertical is non-benign because it is now unable to properly receive its input. This is akin to an SG oriented so that the beam does not even feed into its aperture, e.g, the SG just being in the wrong part of the lab. However, rotating a properly positioned SG...
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    I What is the POVM generalization of Born's rule for quantum measurements?

    Not sure if you stopped reading halfway, but this is precisely the type of objection I was attempting to anticipate in my footnote. I am not advancing a completely universal definition of a "benign tweak", and you can certainly pedantically undermine my argument on these grounds. However, I...
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    I What is the POVM generalization of Born's rule for quantum measurements?

    I want to suggest there is a tacit assumption motivating the Born approach, which I will call "Setup-Error Independence". SEI is simply the idea that a macroscopic measurement device's error/variance/deviation should be invariant under benign changes such as spacetime rotations and translations...
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    A Is there a quantum uncertainty to the number of atoms in a marble?

    It was just you wrote: "What precisely do you mean by localized here? Non-zero amplitude at all points in space?" But that would be the definition of *non*localized, no? What is your meaning of "piece of matter"? Do you agree this is ultimately just some sort of bound state/S matrix pole...
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    A Is there a quantum uncertainty to the number of atoms in a marble?

    Well an atom as an interacting state (which at least to good approximation is made of N electrons/protons/neutrons) is not exactly localized even non-relativistically. A molecule is not exactly localised either. So it stands to reason a macroscopic object is also not exactly localized. AFAIK...
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    A Is there a quantum uncertainty to the number of atoms in a marble?

    I think the question is how it *would* permit it, given the only localized states in QFT are the so-called Knight states. See https://arxiv.org/abs/math-ph/0607044. These do not seem achievable with fermionic fields, which constitute the main part of any detector/material object in our...
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    A Is there a quantum uncertainty to the number of atoms in a marble?

    But doesn't this, perhaps questionably, assume the detector makes strictly local measurements or is itself inherently strictly localized in a way QFT would not permit? See https://arxiv.org/abs/0805.0806, in particular pages 3-5. Also, if we treat the detector as a closed system, where does...
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    B Photon Continuity in Double-Slit Experiment

    Right, I am just asking how exactly this can be done in practice. Typically (afaik) a coherent state is measured by 1) recording the number of clicks across many runs, 2) treating each click as indicative of an individual photon, 3) confirming the distribution of clicks converges to the Born...
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    B Photon Continuity in Double-Slit Experiment

    Sorry for the delay, but I wanted to follow up on this. Suppose we have a macroscopic device which experimentalists would consider a good single photon source. What would be a concrete (can actually be built) detector of appropriate design which we could use to measure this emission in such a...
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    B Photon Continuity in Double-Slit Experiment

    I think the issue I was trying to focus on got lost yesterday- I really was not at all trying to say particle states as eigenstates of the number operator are fundamental. So, above you said: I didn't read this claim as having anything to do with the EM/photon field being in specifically a...
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    B Photon Continuity in Double-Slit Experiment

    How do you reconcile this with the existence of the worldline formalism? To be clear, I am not claiming a photon/any particle has *classical* path, I am just claiming it is reasonable to say the photon/any particle was present along the superposition of possible spacetime paths between...
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    B Photon Continuity in Double-Slit Experiment

    Why not? If this concerns particle indistinguishability or higher dimensional configuration space, I think this position confuses Fock space indices with the localized wavepackets that actually matter/interact in the real world. See https://arxiv.org/abs/1002.2544 What is a (non-theoretical...
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    B Photon Continuity in Double-Slit Experiment

    I'm not really talking about an exactly valid number operator though. I'm thinking about what I quoted in #58. I agree Fock states are only truly asymptotically valid in QFT (though I am unsure if this still holds in string theory, so perhaps this is a symptom of underlying pathologies in...
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    B Photon Continuity in Double-Slit Experiment

    Aharanov/Vaidman do their work in optics. Haroche I believe uses cavity QED. But I am not sure this matters, as these are actual experiments, not theoretical models. However photons/light behave in reality, these experiments are certainly telling us something reliable about this. Agreed...
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