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Possibility of Quantum Event

  1. Dec 27, 2016 #1
    Is Quantum Mechanics robust enough to warrant the belief that given enough observations, somewhere in the universe, at least one cat (or anything for that matter) has come into existence via quantum fluctuation?

    If so, then P(C) = P(C | N)*P(N), where C = cat, N = # observations. If N = infinity, then it seems that you could get anything that you want, and P(C) = 1. However, if N < infinity, then at what point would P(C) < 1?

    This seems wrong to me; but I cannot put my finger on it. I sense that something is wrong in the math, and/or that something is wrong with the Physics. Thoughts?
     
  2. jcsd
  3. Dec 28, 2016 #2

    Nugatory

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    Vacuum fluctuations aren't what you're thinking they are and they don't do what you're thinking they do. You might give this Insights article a try: https://www.physicsforums.com/insights/vacuum-fluctuation-myth/
     
  4. Dec 28, 2016 #3
    Yes. Thank you, that article helps a bit. There does seem to be a persistent belief that quantum mechanical probability waves are real waves delivering real particles that MUST really correspond to physical actualities in time. Is it the case that a probability wave of this sort truly carries the information to convert my mother into a cat? Some think so; but I think that they are bonkers. Even if it did carry that information, it seems that other factors prevent such a transition. Back to the books for me.
     
  5. Dec 28, 2016 #4

    ZapperZ

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    Whose persistent belief is that?

    The wavefunction exists in a configuration (Hilbert) space. What makes you think from such a description that these are "real waves"?

    Zz.
     
  6. Dec 28, 2016 #5
    I do not think for one second that probability waves are real waves; but I do talk with people who think that they are, and that they actually exist outside of our minds. There seems to be some belief among the experts that the waves are real; but there also seems to be plenty of experts that disagree. I guess this boils down to the the reality of the QM p-wave, and the debate over which of the 8 or 9 interpretations of QM are true, if any. Personally, I think that they are really cognitive things (meaning only that I think of it) that correspond to physical things. Nothing else. They describe particles rather than provide them. I'd like to find a source that says so explicitly.
     
  7. Dec 28, 2016 #6

    ZapperZ

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    Who exactly are these "people"?

    What in the world does that mean?

    Can you please provide sources for these "experts"?

    I have no idea what this means, especially when it lacks any reference support.

    Zz.
     
  8. Dec 28, 2016 #7
  9. Dec 28, 2016 #8
    Probability waves are math, not physical reality. Math and Physics are at best, representations of reality.
     
  10. Dec 28, 2016 #9

    ZapperZ

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    Then we have a very different interpretation of what is "real".

    Please note that when you ask about the quantum mechanical probability WAVES, you are referring to a specific entity in QM. You are not referring to the entire quantum formalism. You asked if these waves are REAL. You are not asking of QM's formalism is real.

    We do NOT measure quantum waves. We measure the OBSERVABLES that are described by these wave function. There is a difference.

    The reference you referred to is the idea of realism, and whether the classical idea of realism (i.e. a definite value already exists even if we don't measure it) is still valid. This is NOT a question on whether the probability waves are real!

    As is the case, what you ask is as important as the answer you seek. Otherwise, confusion and confusing discussion like this will occur. You need to figure out what exactly are you trying to ask here.

    Zz.
     
  11. Dec 28, 2016 #10
  12. Dec 28, 2016 #11

    ZapperZ

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    OBSERVABLES and classical realism!

    https://www.physicsforums.com/threads/possibility-of-quantum-event.898501/#post-5653332

    Zz.
     
  13. Dec 28, 2016 #12
    I am not trying to confuse anyone ZapperZ ... just trying to come to a better understanding, and therefore give a better response to the persons that I am referring to. I am not sure why you are upset with me, but it is becoming quite a bother. If you could just answer my questions without chastising me, that would be appreciated; otherwise, please move on and let someone else help me out.
     
  14. Dec 28, 2016 #13
    I started this topic with a question about can QM provide us with warrant for a belief that a thing can spontaneously transition into another thing. I DO NOT think that it can; but others claim that this is so. They are convinced that QM can somehow do this. I have no idea why; but would like to offer more than what I have done so far, which is to point out that p-waves do not do this. Is there something else in QM that would warrant such a ridiculous belief?
     
  15. Dec 28, 2016 #14

    ZapperZ

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    The problem here is that YOU are the one who is confused. I spent time and effort in my previous post trying to untangle this confusion. You seem to have ignored it.

    Please do not provide me anymore references, because none of these are addressing what I was asking for. You are confusing the idea of non-classical quantum realism, with the idea that people are actually measuring these "probability WAVES". We do not measure these waves. We measure these "observables", such as position, energy, momentum, etc...

    I would think that you want to understand this first. If you do not, then you may ignore all of my posts here.

    Zz.
     
  16. Dec 28, 2016 #15
    It may be worthwhile to point out that "Boltzmann brains" is a similar idea, although it's about thermodynamics not QM. Google it if interested.
     
  17. Dec 28, 2016 #16
    True. Isn't the Boltzmann Brain thing more of a reduction ad absurdism against what I am inquiring about. At least that is my current understanding of that idea.

    I am looking for a set of reasons to deny that QM can provide warrant for the belief that anything, such as a rock or planet can either pop into existence from "nothing" (so to speak), or that a rock or planet could transition to something else, like a cat. I keep running into people who are or have been convinced that QM provides a warrant for such belief, and it seem outrageous to me.
     
  18. Dec 28, 2016 #17
    Well, cats do appear from planets don't they? It just takes some time.
     
  19. Dec 28, 2016 #18

    Nugatory

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    That's easy.... Pick up any first year textbook, see if it says anything even remotely like that. It won't.
    Many misconceptions about quantum mechanics have been passed down from one popular science writer to another. This happens with just about any technical subject, of course, but QM does attract an unusual number of distortions.
     
  20. Dec 28, 2016 #19
    I have looked at a few introductory textbooks on the matter, and YES ... they DO NOT give any warrant for what I am asking about. It's the writing that comes higher in the food chain that worries me, such as the popular writers who are sometimes experts in the field.

    This entire thread has been quite helpful though in exposing how the technical jargon gets muddled by semantic interpretations that do not correspond to the math. That is a tough thing to unravel, indeed.
     
  21. Dec 28, 2016 #20

    bhobba

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    Physics is written in the language of math but is not math.

    II don't know what you mean by just math, in fact I see that written quite often and have zero idea what is meant. Math is a language. It's like saying Shakespeare is just English - you go - huh.

    The question is are quantum states real like a table is real. That is very interpretation dependent. Without specifying an interpretation its an unanswerable question.

    Thanks
    Bill
     
  22. Dec 28, 2016 #21

    bhobba

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    That's because you are asking the wrong questions. Of course things can pop into existence from 'nothing' so to speak eg photon number are not conserved. All of a sudden an atom can spontaneously emit a photon that was not there before. The reason lies in Quantum Field Theory where the electron is coupled to the quantum EM field that permeates all space. Work through the math and there is a definite chance this will happen - in fact 100% for sure it will definitely happen - its just a matter of when.

    Can cats pop into existence like a photon? Maybe - but with a probability so close to zero you can forget it. Even in classical physics there is a chance all the atoms in the air will travel in the same direction and lift you up - the chance though is so negligible you can forget it.

    In physics there are quantities so close to zero it is for all practical purposes zero. Don't be too worried if you don't get it yet, some for some reason never seem to get that one even though its used in applied math (not just physics but many area where math is used) all the time - and some (admittedly very few) are highly qualified professionals who argue since its not exactly zero you cant assume it is so your explanation where its a very small value so is taken as zero is wrong.

    Thanks
    Bill
     
    Last edited: Dec 28, 2016
  23. Dec 29, 2016 #22
    I agree that math is just a language...one of many representational systems. It does not exist like objects do. We think of ways to describe objects, motion of objects, etc. Math is just one way to do that.
     
  24. Dec 29, 2016 #23
    OK...then what are the right questions that I should be asking then?

    While I wait, how about these?

    1. Is it true that the likelihood of virtual particles popping into and out of existence is 1 since it happens all of the time? Casimir Effect? Based on experiments, it seems silly to question that empirical fact that conforms perfectly well to theory.

    2. Some macroscopic object popping into existence is nonsense because the quantum foam does not produce such things? You would need the quantum foam to give you everything that is needed for magic to happen elsewhere?
     
  25. Dec 29, 2016 #24
    Virtual particles do not exist, there are plenty of threads about that issue.
     
  26. Dec 29, 2016 #25
    Ask yourself this. When you watch the television are they the same photons hitting your retina as the ones that were bouncing off the actors?
    If you would like to stick to a particle model entirely I can't see how one could dispense with virtual particles..for how likely is it that a detected electron is the one you started with?
     
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