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Perhaps quantum physics is elegant, but we lack an understanding?

  1. Oct 30, 2004 #1
    Well, unlike other areas of physics where the rules are predictable 100% of the time and every aspect can be known with definite precision, quantum dynamics is not as elegant.

    For example, we can know the position of a an electron, but not it's speed or so on, or something like that. Perhaps the quantum world is so hectic and not as elegant because our current equations and laws are not sufficient to let us view them correctly?

    The current equations for quantum physics are genius, but could it be that they are no sufficient and that no brilliance could ever unlock an elegant view of quantum mechanics?
     
  2. jcsd
  3. Oct 30, 2004 #2

    ZapperZ

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    It isn't QM that is dictating this. A theory cannot dictate what Nature is. The "other areas of physics" only APPEARS to have rules that are "100%" predictable, because they do not deal with the scale and the conditions that QM has to deal with.

    BTW, here's something to think about - if QM isn't "predictable", how come your electronics work predictably, or that you would trust your life in, for example, an MRI?

    Zz.
     
  4. Oct 30, 2004 #3
    I read an article once that complained a lot about how QM was just a device for fitting the known data to some equation, a curve fitting process. It seems that we don't yet have the fundamental principles from which QM is derived.

    I have a suspicion that I think should be fully investigated by those more skilled in the art. I suspect that there is a conservation of information law at the heart of QM. In QM each alternative possibility has a probability of that alternative happening. Each alternative should have some entropy or information associated with that particular alternative. Paths that are far from the classical limit would have more entropy, etc. So there is information associated with the structure of each alternative, and there is information associated with the probability of that alternative happening. I suspect that these two sources of information would be equal and form some sort of conservation of information law.
     
  5. Oct 30, 2004 #4

    ZapperZ

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    You could say that with every physics principles. So why pick on QM alone?

    Secondly, what exactly is meant by "the fundamental principles"? People throw this around as IF this is something that is obviously known.

    Zz.
     
  6. Oct 30, 2004 #5
    Well, let's see. QM gives a classical limit, but we don't know why QM should be necessary other than it fits the data. Also, there is the search for Quantum Gravity, and there is a few approaches being tried: Loop Quantum Gravity, Dynamical Triangulation, String Theory, etc. So it would help if there were a principle that determined which QM approach is correct.

    Right. What I mean by fundamental is some principle which is undeniable because it comes from reasoning itself. For example: reality is a topology because it seems undeniable that unions and intersections of parts of reality are also parts of reality. Likewise, it seems undeniable that the universe as a whole cannot lose information... where can it go except somewhere that we also include as part of the universe.
     
  7. Oct 30, 2004 #6
    Have you ever seen a real experiment where the initial conditions are given with an infinite precision (e.g. classical mechanics)?

    All the known experiments (at least, the ones I know) involve some uncertainty.

    Therefore, what is the strangest? a theory allowing a possible system description with an infinite precision that has never seen in any experiment or QM theory postulating the uncertainty on the knowledge as a fundamental point?

    If I take only the existing experimental results, I will be more confindent in QM theory than in any other theory allowing a deterministic (non statistical) description as a postulate.

    Seratend.
     
  8. Oct 30, 2004 #7
    Well sometimes, even an electronic device commits some errors :tongue2: (for example a CMOS inverter, has a probability - very low - to give some errors as any detectors- it is sometimes basically modelled with a noise signal).
    And when I take a software program like w......s on my computer, I really believe in QM or may be in gremlins :biggrin:

    Seratend.
     
  9. Oct 30, 2004 #8

    ZapperZ

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    First of all, there seems to be this "trivialization" of the fact that "QM fits the data". Irregardless on whether this is really an accurate statement, the fact that something AGREES with an experimental measurement should be already an astounding observation.

    Secondly, you seem to think that all of QM is nothing more than phenomenology. If this is so, then I question your understanding of what QM is. QM just doesn't FIT data. How did Dirac "fit" his data to came up with the existence of antiparticles? There were no "data" to fit! How did Luttinger "fit" his data to came up with the spin-charge fractionalization when it hasn't been discovered back then?


    So where in physics do you get this? Nowhere! Again, why pick on QM only?

    What you want is MATHEMATICS. Physics starts and ends with physical observation. It is why there are postulates that appear not out of First Principles, but out of numerous observations. There are no First Principle derivation for the constancy of the speed of light, nor the conservation of momentum. These cannot be arrived at simply by logic, because they are the physical principle of the universe we live in.

    You should not confuse the fact that the physics (from the level you understand it) doesn't fit your world view with it being not having a "fundamental principle". Maybe the "lack of understanding" in the title of this thread should FIRST be directed inwardly to make sure none of what is being claimed is based on ignorance of the subject matter.

    Zz.
     
  10. Oct 30, 2004 #9
    Are you trying to ask "what is so physical about information?"

    Basing postulates on nothing more than observation only begs the question as to why things are as they are. It is the same as giving up on the search for truth. It is an arbitrary choice to be content with a particular set of observations when more detailed observations require more detailed answers. It is not possible to finish with inquiry until the answer stem from the principles of reasoning itself. So physics will not be complete until it can be derived from logic. Anything less is just stopping for a moment to look at your accomplishment in order to be proud of yourself. :grumpy:

    Even conservation law are based on invariance principles acording to Noether.
     
  11. Oct 31, 2004 #10
    Well, you should look at godel incompletness theorem (1931) and even with mathematics a consistent theory may be taken as wright or wrong (you cannot demonstrate it is wright or wrong).

    Your own reality seems to be a little bit too restrictive comparatively with the current physical models: in this case, Reality is more a sigma-algebra than a topology.
    And if you look further on, you will discover that all the currently used physical models are based on the set theory, say zermello-frankel axiomatic set theory (unions, intersections, etc...). It is a consistent theory: you can take the axioms as true, what we impliciteley do with the current physical theories or you may assume them false.
    Even the mathematical logic is not able to say if reality is true or not!

    You are asking for the completeness of physics based on mathematical tools that are "incomplete" by principle.

    Mathematics have discovered the modesty with persons like Godel during the first half of the 20th century like classical physics with the advent of quantum physics.

    Sometimes, it is good to know the limits of our current logic and structures. One of the most simple examples is: the set of all the possible sets is not a set.

    Seratend.
     
  12. Oct 31, 2004 #11

    ZapperZ

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    I could play your game too. I could ask, so why is there "invariance principles"? Such symmetries are NEVER derived logically. They are only realized after all the observations that are made. Just look at the history of discoveries that led to Noether to arrive at that conclusion. It was based, FIRST, on the discoveries of all those conservation laws based entirely on observations. Thus, those invariance principles are NOT derived out of some "fundamental derivations".

    I still question your understanding of QM to be able to question it. This, you have never addressed in this and all your postings.

    Zz.
     
  13. Oct 31, 2004 #12
    Nobody has ever started with mathematics and derived the universe. I think it can be proved that this is always impossible. Mathematics and reasoning without observation clearly alllow for an infinite spectrum of 'possible' universes. Most of these would be nothing like the observed one we live in.

    Basically, the whole thing doesn't work like that and never has. When you introduce observation you then can make predictions based on experience. This is reasoning isn't it?
     
  14. Oct 31, 2004 #13
    The effort to complete physics is not the same as the effort to complete mathematics. We are not trying to find every single mathematical expression which is true or provable within mathematics. That's not what physics is trying to do. In fact, we are looking for only one equation, not all of them, that describes our reality. Therefore, Godel's Incompleteness Theorem is irrelevant.


    Basically, I think we are getting quite close. When we start to think that spacetime itself may be a quantum mechanical superposition of various geometries, all we need is a more fundamental reason for accepting QM superpositions to begin with, and we may be done. I am of the opinion (though not proven yet) that some sort of conservation of information law is at the heart of QM.

    The problem is that if you do not have a physics based on principles of logic itself, and instead have one based on curve fitting of prior observation, then you can never really say that things could not be any other way. As far as you know, something fundamental could change and physics could start operating differently than it did in the past. You can't say that it won't. But if physics were derived from logic (reasoning) alone, then everyone would have to conclude that physic could not change.
     
  15. Oct 31, 2004 #14

    ZapperZ

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    CURVE FITTING. So then I was right. You have an erroneous impression that QM (and physics, in fact) is nothing more than phenomenology.

    I have shown why this is incorrect (refer to Dirac and Luttinger examples). The whole area of phase transitions IS the study of things that simply will not "fit" into any smooth "curve fitting".

    Have you ever considered the possibility that it is your knowledge of QM that is faulty here? "Imagination without knowledge is ignorance waiting to happen".

    Zz.
     
  16. Oct 31, 2004 #15

    russ_watters

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    It may surprise you to learn that QM has produced the most precise and accurate predictions of any theory, ever. Strange, that this would come from a theory that says some things can't even be known, huh?
    That's Aristotle's view - everything can be figured out via logic alone. Its quite obviously an invalid approach to science: it has been used in the past and gives wrong answers about how things work.
     
  17. Oct 31, 2004 #16

    ZapperZ

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    I'm sorry, but you are pointing to a site that claims some work to be "irreverant", and you're accusing me of being pretentious? Hello?

    The "terminal problem" here is that we have the ignorant who are claiming to know everything, when in reality, they don't know when something new comes along even when it bites them on their rear end.

    http://insti.physics.sunysb.edu/~siegel/quack.html

    Zz.
     
  18. Oct 31, 2004 #17
    See:
    http://arxiv.org/abs/quant-ph/0205039
     
  19. Nov 1, 2004 #18

    ZapperZ

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    Good grief! THIS is what you have been trying to champion?!!

    Again, it appears that you are confusing between the formalism of QM and the interpretation of QM. Read carefully the very text you are refering to. ALL the formalism of QM are INTACT, whether you believe him or not! The equation for an entangled state is still IDENTICAL! Of course, you would have known that had you learned QM.

    This is a paper on how to look at the SAME formalism differently. It would be nice to know if it has been published anywhere (or do you not care?). This belongs more in the philosophy section than on here.

    Zz.
     
  20. Nov 1, 2004 #19
    What formalism am I trying to change? I did not even write an equation yet. I am merely suggesting a reason for QM the way it is today. I wasn't trying to change anything. Your criticism is presumptuous at best, it is a strawman at worst.
     
  21. Nov 1, 2004 #20

    ZapperZ

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    You are correct. It was presumptuous of me to assume that you have very little formal knowledge of QM based simply of what you have written. I AM wrong in making this assumption, aren't I?

    Let's see what you have written:

    You shouldn't be talking about making a "strawman", when you REPEATEDLY make the claim that QM is nothing more than a glorified curve fitting. If it is, then keeping the formulation, but changing its interpretation changes NOTHING. That's the same irrational act as changing NMR into MRI so that it sounds more "safe". If you truly believe that QM is nothing more than curve fitting, you should also be weary of that website you proudly cited, since he did nothing more than change the color of the stripe on the tiger. The formulation is still identical! Nothing has changed, except your "feelings" towards it.

    Zz.
     
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