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Quantum fluctuations

  1. Nov 27, 2003 #1
    Hey guys!

    As of lately, i've indulged deeply into the entire affair of Quantum Mechanics, field theories and the like, all in an attempt to comprehend how the universe came out to be, what caused it, and what is it's ultimate fate.

    Despite my sincere efforts, and after reading plenty of all-encompassing materials about elementary particle, superstring theories (supersymmetry and the like), multiverse universes, etc, i'm still having some issues.

    More concretely, about a month ago i began to realize that perhaps the "all-knowing, all-powerful, all-good" notion of god is severely lacking in several distinct ways: the quantum fluctuation idea (virtual particles) entangled me with the concept of creation of "empty space", and perhaps the stencil of "god" could be supplemented by "quantum fluctuations and quantum fuzziness".

    My question to you is the following: if the universe was indeed created out of nothing (vacuum, courtesy of Heisenberg's uncertainty principle), then what exactly was beforehand? what governs the quantum fluctuations? now i agnize that it's the beauty of quantum theories that remains an undeciphered mystery for many centuries now, but unless the Casimir effect as they say (hope i'm not scrimmaging those two up) had a reason to be excited, it all regresses to the very beginning.. who says it's legible for quantum mechanics to govern it all?

    I'm a bit perplexed here guys, so i could use some help.

    Wholeheartedly, Dima
  2. jcsd
  3. Nov 27, 2003 #2
    If you're talking about a model in which the universe is created from vacuum, then what was beforehand was vacuum.

    The general answer to your question is simple: we don't know what, if anything, preceded the Big Bang. We don't even know if the universe as a whole (as opposed to, perhaps, our little pocket of it) was created, or whether it was created out of "nothing" (whatever that means).

    The laws of quantum physics. If you mean, what determines which particular fluctuation is going to occur, nothing does: they're random.

    What do you mean, "regresses to the very beginning"? Do you mean you always end up with something unexplained by physics? No physical theory will ever "explain everything", including itself. No matter how the universe got here and what the laws of physics are, we'll never know why the universe has the laws it does.
  4. Nov 27, 2003 #3
    Yes, that's what i meant... i'm having difficulties coming in grips with the thought of this "nothingness", vacuum and that sort of stuff, but guess that's the best we've got, so i'll grab the gist of it in the end :)

    As to the Big Bang: superstring theories seem to be the best candidates for elucidating it's nature, or whatever that maybe... perhaps the two membranes (one our universe resides one and a parallel one) carrying some form of energy came to a direct collision, thus triggering the Big Bang... in that case though, it seems as if the Big Bang is nothing extraordinary or the "beginning of it all", but merely another event in the ever unfolding, "infinite" cycle of cosmic calamities... the question unanswered is still intact: what triggered it all? it seems no theory is able to account for all of that...

    But why are they random? all the quantum mechanical concept is extremely engrossing, but the overall nature seems elusive at best... they're random you say, but that pretty much delves deeper into your comment further below.

    That's exactly what i meant m8, and that is the snag i wanted to convey, but the fact stands straight: human beings (or other civilization to follow) will always crave for more, but as you say, we'll never know why the universe has the laws it does, then isn't it pointless to talk of all the probabilities, uncertanties and god knows what of quantum mechanics, when, as i mentioned above, we'll never truly recognize it's intrinsic nature? the fluctuations are random, thus, even if they did harness the "power" of the virtual particles, what governs their behavior? who permits their randomness to be distributed anywhere and everywhere, and ultimately, is the "vacuum" really the source of these outcomes?

    I appreciate your time for answering my question.

    Last edited: Nov 27, 2003
  5. Nov 27, 2003 #4
    We don't know. If they weren't, then we'd just be asking the opposite question: why aren't they random?

    We don't know of the "intrinsic nature" of anything, in science or otherwise. Should we just stop talking, then? As for science, we have theories that correctly predict the outcomes of experiments. Most people would say that's because we know something about how the universe works, regardless of whether we'll ever know everything.

    I'm not sure why you're singling out the probabilistic nature of quantum mechanics here ... for any theory X, you can ask "isn't it pointless to talk of (insert whatever X says here) when we'll never know its intrinsic nature?"

    Quantum fluctuations don't have anything intrinsically to do with vacuum; they have to do with the quantum laws of physics, which say that observable quantities don't all have simultaneously well-defined values.
  6. Nov 27, 2003 #5
    It looks to me that you are coming to this subject with certain religious beliefs, or at least a philosophy that there is a 'reason' for the Universe being the way it is.

    If you find it hard to understand the complexities of QM, BB theory and indeed the Universe itself, then join the rest of us!!

    If however you are trying to 'fit' the physical world we observe to some idealised 'Creator' or indeed any other deeply held belief (religious or not), then you are on an impossible task.

    Must there be a why? Physics looks at what the Universe is, and tries to understand and explain the way it works. If you want a WHY, then perhaps 'Quantum Physics' is the wrong forum?
  7. Nov 27, 2003 #6
    You're correct, guess some questions are just that: meaningless...

    I'm singling out the probabilitic nature of quantum mechanics, not because it doesn't make sense, or doesn't comply to the observed results from experiments, but as a result of an obscure nature of the theory: it's ambiguous intrinstic nature, which we'll never fully leverage, or at the very least, get a glimpse at.

    Yes, you're right, i blundered out this no-sense for some unknown reason, sorry for that. What i meant to say is this: the inherent principles governing quantum mechanics, which we are unaware of, transfer to it's probablistic nature, which has been probed deeply with various contraptions over the course of history, but this all boils down to this: we'll never know why the universe has the laws it does, hence, quantum mechanical nature manifests itself in something shallow, which is perhaps beyond the intellectual of our civilization...
  8. Nov 27, 2003 #7
    I still don't see what you're getting at. If the universe were non-quantum and deterministic, how would we "fully leverage its intrinsic nature" that, or "get a glimpse of" it?

    Again, what does that have to do with quantum mechanics, as opposed to any other theory?
  9. Nov 27, 2003 #8
    Re: Re: Quantum fluctuations

    We've reached consensus on this issue indefinetly, but there is an insurmountable ostacle: peradventure, i'm trying to coalesce creation to the inevitable question of reason and cause, but rest assured, i don't hold any religious (or differentiated away) beliefs regarding anything... i believe it's preposterous for the "all-knowing, all-powerful" being to have created the abode we know call "universe", but coupled with that is the notion that if proven otherwise (which is highly unlikely, mildly uttered), i'm more than prepared to accept the entaling outcome!

    I surmise a machinate approach to the whole affair would mark a deviation of the physical laws and the principles they're governed by, but that would live up to my hopes of ever realizing why the universe has the laws it does...
    Last edited: Nov 27, 2003
  10. Nov 27, 2003 #9
    We would understand it's underpinnings and why it has the laws it does... quantum mechanics just makes it impossible for us, again, a by-product of it's probablistic nature.

    Come to think of it, it doesn't... the ultimate question goes beyond any theories...

    It seems the univese is one gargantuan ambit which is mediated by quantum mechanics on the small scales, and general relativity on the large scales... the unification of all the forces and eventual inclusion of gravity into the equations (perhaps by finding the elusive graviton and proving it's siphoning to membranes on higher dimensions), will beacon and solve the biggest knot of science, but that still won't answer my question.
    Last edited: Nov 27, 2003
  11. Nov 27, 2003 #10
    That certainly is not true. (Is that why you wrote "Come to think of it, it doesn't"?) If the universe was classical, we wouldn't have any better idea of why it obeys the laws it does than if it was quantum. It would just obey different laws. The question of why the universe has the laws it has is unanswerable within physics, regardless of what those laws are.
  12. Nov 27, 2003 #11
    Your arrogations are amenable to no better explanation, but i'm still connived by this enigma... for instance, superstring theories suggest that the strings themselves can move in the 6th dimensions, since equations pretty much dictate them to obey this rudimentary (or so it seems) principle, but what governs their movement?
  13. Nov 29, 2003 #12


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    Hey, we don't even know if this theory stacks up, let alone how to go another layer deeper! The good news is that, taking one wild extrapolation of the speed of development of physics, it'll only take another 50 to 200 years before this question will indeed have some kind of an answer (assuming ST becomes mainstream in the meantime).
  14. Nov 29, 2003 #13
    Re: patience

    You're right, but the crowning question will still be high on it's toes: why do the laws of nature operate they way they do? fine, so perhaps in 50-200 years (as you said), we'd be provided with an answer why the desirable constants value for life were embedded in the particles, but that still wouldn't hold a nobel prize for an answer to this riddle :(
  15. Nov 29, 2003 #14


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    Wrong place?

    If that's what you're looking for, then my advice would be to look elsewhere, maybe philosophy or a religion. As it operates today, the scientific method, which is the basis of science, will always open up more questions, and there will always be scientists who seek to answer them.

    But, you never know, maybe science in the 2341st century will be so different from what we use to explore quantum cosmology that we wouldn't even recognise it.
  16. Nov 29, 2003 #15


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    Present day religion and philosophy have answers, but oh how woefully weak and beside the point they are when it comes to why the universe is the way it is. Religion says it is so because some supernatural force or other made it that way. But why did the supernatural force do that? Maybe some answer is suggested. But why should that answer be so? And so on into infinite regress.

    And philosophy has just about given up on telling about the world, and retreats into pseudo psychology and such.

    If traditional lore can't answer the question and science won't consider it, where is the human heart to turn?
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