QM randomness...

Discussion in 'Physics & Math' started by Seattle, Jun 2, 2017.

  1. The God Valued Senior Member

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    You forgot so soon? Pl refer your post #18, you have used it no less than 3 times!


     
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  3. iceaura Valued Senior Member

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    Sorry about that. I did forget. I was attempting to communicate with the poster who used the term in post 13, in quotes.

    It just means not pseudo-random, not like a coin flip or a computer generated random number but instead lacking cause/effect explanation.
     
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  5. The God Valued Senior Member

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    I did use the same in #13 asking the meaning of same. You did use it emphatically in #18 to make a point about QM.

    Anyways there is nothing like true randomness, that alone will bring us back to determinism sooner or later. QM may not be wrong, it is just that something is amiss.
     
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  7. Schmelzer Valued Senior Member

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    Just for information: Quantum theory has a deterministic interpretation, namely de Broglie-Bohm theory. Bell's theorem says nothing against dBB theory, because it is non-local. Which is well-know. In fact, the aim of Bell's theorem was to support dBB theory: The most powerful argument against dBB, that it requires a hidden preferred frame, is worth nothing, because any realistic interpretation has the same problem.

    Then, even if Bell's theorem is often said to forbid local realistic theories, in fact it forbids only Einstein-local realistic theories. Theories with finite but much higher speed of information transfer would be unable to give QT exactly, but approximate as close as necessary.

    So, given that quantum theory has a deterministic interpretation, it cannot prove anything about "true randomness" and so on.
     
  8. iceaura Valued Senior Member

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    Any determinism that accounts for Bell violations will establish "true random" patterns (no cause/effect structure).
    That speed is growing rapidly as the measurements get more precise - it is too high to persuade most people I run across lately. The intuitive problems with a seemingly arbitrary discarding of Einstein for a speed of cause/effect that no one can find any evidence for seem to bother people as much as those surrounding random and uncaused event.
    Quantum theory also has a "superdeterminism" interpretation that seems to me to warrant more and different consideration than it has received.
     
  9. Schmelzer Valued Senior Member

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    No, superdeterminism is simply nonsense. If you prove a mathematical theorem, you have to mention (and exclude) such nonsense explicitly, and this is the only reason to mention it at all.

    Already the speed of light is much to high for our intuitions, as almost all the numbers used in physics. So, numbers "too high" does not make sense.

    Einstein's spacetime has almost religious character now, as an interpretation, and once the Holy Scripture forbids a preferred frame, one is ready to forget about realism and causality and whatever else. (Which is not a rant against relativity as a physical theory, but only against a particular interpretation of relativity.)
     
  10. iceaura Valued Senior Member

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    No, it isn't. And it has nothing to do with proving any "mathematical theorems". They are all timeless and tautological anyway.
    It bothers people. And the lack of evidence, of course.
    Causality as fundamental seems much more faith based than Einstein's spacetime, which is adopted on evidence and commonly argued over provisionally. It has the warning bell characteristic of only working at the frontier, where there is ignorance - where we have thorough knowledge, it dissolves into statistical laws and probability.
     
  11. Schmelzer Valued Senior Member

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    What is has to do with "mathematical theorems" is that Bell's theorem is such a mathematical theorem. And to make it a mathematical theorem, instead of imprecise physical reasoning, it has to exclude any loopholes. This made it necessary to make assumptions which exclude superdeterminism.
    Which lack of evidence? The violation of Bell's inequality is well established in experiments. And if you have any idea about a meaningful explanation for such a violation, which does not involve faster than light information transfer, let me know. See http://ilja-schmelzer.de/realism/game.php
    What makes the difference between statistical observations of astrology and science is that science is not only about correlations, but looks for causal explanation. This is central to science itself.

    But, of course, if one gives up causality and realism, and believes in pentagrams or mystical spacetime symmetries as providing deep fundamental insights, one can as well believe in superdeterminism.
     
  12. iceaura Valued Senior Member

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    English is your second language, so let's just pretend you didn't say any of that confused mess, ok?
    The lack of evidence for anything traveling at such high but finite speeds between things - which as the necessary speed doubles and redoubles, becomes increasingly anomalous.
    Superdeterminism explains it nicely, and so does the admission of probability as fundamental, rather than assuming cause/effect is. Both of them have the advantage of support (or at least no direct contradiction) in established theory and evidence beyond merely assuming they must exist - which superluminal information transfer lacks.
    You probably mean mechanism, not cause - nothing "causes" rainfall, for example, or coming the other way "air pressure" causes nothing (if you break it down to fundamentals these things are statistical patterns, consequences of probability).
    Causal explanation is normally heuristic, a mental shortcut that summarizes a world of lower level patterns of interaction into "things" that "cause" events with probability above a certain threshold. That's whenever we know what's going on.
    If you are happy believing in "causes", or ghosts, or elves, or river spirits, go for it. They do come in handy (all of those things). But you don't have to believe in them for that, and it also may come in handy sometimes to set the concept aside.

    The entire discussion is an example of a problem with trying to ban philosophy from science - the tendency is to get trapped in some long-dead philosophy that has presented as reality, to the detriment of one's scientific efforts. Instead of no philosophy people end up with bad ones.
     
    Last edited: Jul 14, 2017
  13. Schmelzer Valued Senior Member

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    Superdeterminism explains nicely why you have written such a text. You can also explain with superdeterminism (instead of searching for causes in your text) why I prefer EOD instead of continuing the discussion.
     
  14. Neddy Bate Valued Senior Member

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    I admit that I really don't understand much about quantum experiments, but what do you guys think of this article:
    http://cyclesresearchinstitute.org/subjects/cycles-physics/epr/

    One part of the article that does make sense to me is where the poker card analogy is discussed, as follows:

    And another part of the article that makes sense to me is where the light polarizers are discussed, as follows:

    Is this article really pointing out a fundamental mistake in the assumptions made in quantum experiments? Or are there errors in the article?
     
    Last edited: Jul 14, 2017
  15. The God Valued Senior Member

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    This is why (the cause), I used "religious fanaticism" in my earlier post. Anything contrary to your POV on the subject and you get nasty. You attempted on me, I ignored then and now Schmelzer walked out.

    I am just saying randomness or probability may not be fundamental to nature. Determinism is not away from causal as you are mistakenly stating.
     
  16. iceaura Valued Senior Member

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    Elm's objection is that all the researchers finding violations of Bell's Inequality have miscalculated the probabilities involved in the same fairly simple way.
    I don't know whether he is correct, but as he also makes some other claims that appear to be false about the setups (see below example), and the error he claims is kind of elementary (and would have to have been made exactly as he describes over the twenty subsequent years by all the new researchers) I doubt his claim.

    Here is a take by someone who both: 1) understands a bit more about the technical matters Elm refers to 2) thinks he has found a local variable approach of his own (is not defending QM): https://arxiv.org/pdf/quant-ph/9808008.pdf
    btw: That paper is also fairly old in this field, and if you read it you will note that he notes that his new objections could be addressed by experiments with particles such as electrons that have mass. These experiments have been performed since, and produced violations of Bell Inequalities just as the others had.
     
  17. iceaura Valued Senior Member

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    You read nasty in my responses, where it is minor impatience with a familiar troll, and do not read it in your own or Schmelzer's, where baseless insult and personal attack simply flows naturally without motive and without honest trigger.
    So bite me. You want polite, be polite - quit with the "religious fanatic" ascription to reasonable tone and reason itself, say.
    You are claiming that it can't be. You are claiming that some causal factor must exist here. I am observing that actually deriving and presenting one has proven to be difficult, for basic reasons - the very concept of a cause, the intuitive role of it in making sense of things, is in conflict with the kinds of "causes" that can produce Bell violations.
    I'm not. I'm linking them in noting that Bell violations severely constrain their applicability to quantum phenomena simultaneously.

    Superdeterminism, as would be explanatory of the discovery of Bell violations, replaces causation - denies the reality of causation altogether, which agrees with the easily observed universal employment of causation as a mental shortcut or heuristic or even quasi-meetaphor (not a fundamental aspect of reality).
     
  18. The God Valued Senior Member

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    This is also nasty and false and mischievous representation of my claim.


    As early as #15, I said....and after that I had cautious approach by using words like "may" and ,"IMO"..

     
  19. iceaura Valued Senior Member

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    As you say: those are your views.
    A one sentence post, in which your all your "caution" is directed at the forty year consistent and un-contradicted results of multiple and varied experiment supporting repeatedly reconsidered theoretical calculation, and none at what is a plain statement of faith lacking evidence or argument.

    And it didn't have to be. It is, after all, possible to make an argument for suspending judgment in the interpretation of QED, and allowing for something like a reinterpretation of causality in the future. Or logic - some kind of "imaginary truth" value come into play. You could, say, argue that it's happened in the past that all of the finest scientists exerting their best efforts for generations overlooked something that was right in front of them the whole time and - when at last recognized - fundamentally changed their worldview and reinterpreted everything they knew. Darwinian evolution. And this situation feels like that.

    But that would be closer to my posting here than yours.
     
  20. arfa brane call me arf Valued Senior Member

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    In another thread I say that type II SPDC has maximally entangled photons where the two cones intersect. The two cones are where pairs of photons emerge and are horizontally polarized in one, vertically polarized in the other, this is correlation of complementary degrees of freedom.

    I also say that where the cones intersect, it's impossible to tell which cone the photon is in. But that implies (maybe) that each photon is in one or the other cone and is polarized horizontally or vertically.
    You can't actually say that, because the maximally entangled states also have maximum uncertainty. The entanglement is correlated states in superposition, where the superposition is the spatial intersection of the two cones.

    So all you can say is that measuring each entangled photon's polarization will give random results, which should get close to 50% horizontal + 50% vertical. That result is much like an interference pattern--you don't see one until a certain number of 'measurements' have been made. The 'pattern' is the measurement correlations.
     
  21. Schmelzer Valued Senior Member

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    What? is my reaction too, given Bell's quote "Now we make the hypothesis, and it seems at least worth considering, that if the two measurements are made at places remote from one another the orientation of one magnet does not influence the result obtained with the other." Nothing about any comparison of the results.

    David Elm, I remember this freak from USENET time. Forget it.
     
  22. The God Valued Senior Member

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    The doors are not closed on either side. Your stand is very rigid in favour of randomness on the other hand I have feeling that it may be worked out causal way as we pursue further.
     
  23. iceaura Valued Senior Member

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    That implication is what the Bell violations rule out. If the entangled photons were in one cone or the other, Bell's Inequality would hold for all measurements of their status.
     

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