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Technology: More quantum weirdness.

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    Good old Young's Slits
    https://www.youtube.com/watch?v=GlOwJWJWPUs

    Imagine a 3rd screen behind the original screen, and we relocate the detectors at this new screen. Imagine we cut two new slits in the original screen. What will we see at the new screen? Specifically, if the new slits coincide with two original minima, will we see anything at all at the new screen?
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    https://www.sciencealert.com/physicists-think-they-ve-figured-out-a-way-to-save-schroedinger-s-cat
    Seems significant. I wonder if half life can be extended in a like manner.
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      CommentAuthorAngus
    • CommentTimeJun 8th 2020
     
    Definitely weird.
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    "...random collisions didn't destroy entanglement."
    https://www.livescience.com/physicists-entangle-15-trillion-hot-atoms.html

    Surprisingly warm and entangled.
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      CommentAuthoraber0der
    • CommentTimeJun 10th 2020
     
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      CommentAuthorTrim
    • CommentTimeJun 12th 2020
     
    Quantum 'fifth state of matter' observed in space for first time.

    https://phys.org/news/2020-06-quantum-state-space.html
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      CommentAuthoraber0der
    • CommentTimeJun 12th 2020
     
    More quantum filth.
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    More like a state of it doesn't matter.
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      CommentAuthorTrim
    • CommentTimeJun 21st 2020
     
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      CommentAuthorTrim
    • CommentTimeJun 21st 2020
     
    Phonons not photons.
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    Is there a cure?
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      CommentAuthorTrim
    • CommentTimeJun 25th 2020
     
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    0/1: an x-axis electron spin measurement result ("up/down")
    +/-: a y-axis electron spin measurement result ("left/right")

    Consider two subsequent measurements on an electron initially measured as 0.
    There are 42=16 possible a priori results, of which 9 are allowed by QM and 7 are not.

    Allowed:
    1a. 0 0 0
    2a. 0 0 +
    3a. 0 0 -
    4a. 0 + +
    5a. 0 - -
    6a. 0 + 0
    7a. 0 + 1
    8a. 0 - 0
    9a. 0 - 1

    Disallowed:
    1d. 0 0 1
    2d. 0 1 0
    3d. 0 1 1
    4d. 0 1 +
    5d. 0 1 -
    6d. 0 + -
    7d. 0 - +

    The QM rule is that if consecutive measurements are made on the same axis (x or y),
    then the result remains unchanged (aka "collapse of the wavefunction") (e.g. 1a, 4a,5a)
    Otherwise (y follows x or x follows y) the result is indeterminate.
    The "collapse" is "reset" by switching measurement axes (e.g. 7a, 9a) and this is the mystery.

    Consider the pair
    7a. 0 + 1
    1d. 0 0 1
    where the difference is solely in the 2nd measurement.
    Somehow, the act of switching measurement axes in 7a allows the original state (0)
    to become indeterminate on the 3rd measurement. This is incomprehensible to me.

    ref https://www.youtube.com/watch?v=IB50S4J4c8k&list=PLrxfgDEc2NxZJcWcrxH3jyjUUrJlnoyzX&index=17
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      CommentAuthoraber0der
    • CommentTimeJun 26th 2020
     
    Posted By: Andrew PalfreymanThis is incomprehensible to me.

    ++ :|
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      CommentAuthorAngus
    • CommentTimeJun 26th 2020
     
    I don't see that as weird. Consider what you are doing. A single photon is being passed through a polarising filter. If it is polarised vertically and the filter is vertical it goes through with a 100 percent chance of appearing to be in its original up or down polarisation state. If it is horizontally polarised and the filter is vertical its spin state is forced to appear vertical, which it does by getting resolved into its up or down components with some probability. (That's the weird part). What can not happen is that you resolve a polarisation state into the opposite state (say up->down or left->right) because up has no component of down, nor left of right. So 0+1 is allowed because the first state (0,1) does have components (L,R) and the second states L,R do have components (0,1). But 001 is not allowed because the second 0 state has no component of 1.
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    You seem to be missing the point. And if you wish to comment, do please use my nomenclature. Saves me having to reinterpret and then restate everything if I reply.

    I am focusing on the fact that the "collapse" is magically reset by making an orthogonal measurement. Perhaps you'd like to comment about that?
    7a. 0 + 1 is allowed, as is
    6a. 0 + 0.
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      CommentAuthorAngus
    • CommentTimeJun 26th 2020
     
    I did use your unacceptable symbols, but just because I can't be arsed to do bras and kets.

    There is no collapse. You can't pass the photon from filter to filter if you detect it. Therefore there is no collapse until the final filter is passed.
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      CommentAuthoralsetalokin
    • CommentTimeJun 26th 2020 edited
     
    Nothing collapses until God sees it. In other words, the final filter is a conscious observer. In other words, it's all fuel for the shitrocket.

    Sorry, it has been a long day. Pray continue without collapsing the discussion.
  20.  
    Posted By: AngusThere is no collapse.
    I'm afraid you'll have to watch that darn video if you're to have a hope of getting the context of my remark, which is pretty much verbatim Carroll. Sorry.

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