Naked Science Forum
Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: David Quinn on 02/02/2004 00:51:24
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I was wondering if an expert in quantum physics can clarify a couple of things for me.
I read this in the Wikipedia:
quote:
Interpretation of Quantum Mechanics:
Quantum mechanics is a physical theory which is extremely non-intuitive. The equations have been very successful in predicting experimental results, but there have been a wide range of interpretations of what those equations mean.
The need for a large range of interpretations of quantum mechanics becomes clearer once it is mathematically demonstrated that no quantum theory can have all of the properties one would like quantum mechanics to have.
One inituitively would like a theory of quantum mechanics
- that is complete and not requiring any outside theory
- that is local in that the events at one point are only effected by nearby areas
- that is deterministic which is that given one set of circumstances, there is only one possible outcome
- that has no hidden variables
- that predicts only one universe
However, Bell's theorem appears to prevent quantum mechanics from having all of these properties. Which property is removed results in different interpretations of quantum mechanics.
This seems to suggest that are at least five different interpretations of quantum mechanics, each one the result of eliminating one of the five properties listed above.
My questions:
(a) Do any of these interpretations conflict with what is physically observed in the quantum realm?
(b) Do any of these interpretations hinder the practical application of the theory and its equations?
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I usually respond to quantum related topics, but I can't answer this. I just know that quantum mechanics is non-intuitive, and as I've said before it seems to me that it is just a mathematical fit to the data, not an explanation of anything. But I'm certainly no expert.
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John
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To clarify your question a) we don't actually observe anything in the quantum realm. Our buddy Heisenburg figured that one out. Direct measurement of a particle introduces uncontrollable and unpredictable disturbance. What we CAN do is make predictions in the macroscopic realm based on quantum theories and then test those predictions.
For instance, the photoelectric effect and the cooling technique used in by the physics lab in Boulder, CO to achieve near absolute-zero temperatures are based on certain quantum theories...and they can't be predicted or explained with classical physics.
With that being said, I don't have an answer for you. [:P] Anyway, it sounds like the person that wrote that Wikipedia entry really doesn't like Schrodinger's wave-function theory.
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I remember reading a book about quantum mechanics and I rejected what it was saying in my mind because I didn't like the idea of a set of rules for the big world and another for the little world. It's like in ancient times when they thought there was a seperate set of rules for heaven, and for earth.
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But small particles don't behave the same way as macroscopic objects....they HAVE to have a different set of rules. Just as children behave differently from adults, they must have a different set of rules, as well.
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This is where I disagree. Everything is a form of energy. It would make sense that macro and micro behave generally the same(maybe some variation), because they are the same. Try viewing Macro-Micro together instead of sepertately. Maybe matter,atomic structures, sub-atomic structures, and space are all the same, but in a different form. Say Matter decays to Atomic energy, then to Sub-atomic energy, then to Space(zero point energy or AEther), then maybe to some sort of Pre-Space. No mass, no existence. except as space. This may help explain Quantum Jumps when the Heisenburg Uncertainty Principle is applied. Since the energy at the subatomic would be so close to the line between existence and space, simply being observed could effect it. (H's UP-Observer effects the obversed) and result in a jump of a particle to a different orbit. Or maybe that particle DID decay to space, but matter has also decay releasing energy to take the place of that particle. resulting in a jump. I would bet on the later. And i agree with Tweener as far as the mathematics.
Q+A=Knowledge^2
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It WOULD make sense for subatomic particles to behave the same way as the macroscopic world, but...they don't. I don't that's in dispute in any part of the physics community. They're related in some mathematical sense, but not the same.
I'm halfway through an article right now on a theory supporting the quantization of time-space. I think that might add something to the discussion of the relation between space, matter, and energy in the quantum world. I'll say more after I finish it.
But certainly much of quantum theory is a mathematical fit to weird data, as John mentioned. However, those equations that "fit" the data are being used to predict other phenomena, so while they may not be the answer to life, the universe, and everything, they're viable enough at this point to be useful.
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Actually, macroscopic "particles" do behave the same as quantum particles. The real difference is that they are big (many orders of magnitude) by being collections of quantum particles. In this state, the quantum effects average out. With careful observation they can be seen to exhibit quantum instabilities, quantum spin, quantum electronic properties, etc.
You can calculate the probability that the earth will undergo quantum tunneling. It is so low that if every star in the universe (using the highest estimated number) had many planets, it would still be many orders below 1 for it ever happening in the whole life of the universe.
Years ago I found a terrific book called "Physics III" by Savylev (sp?), translated from Russian. It is a very small thin book, but each chapter has more information than some full sized textbooks. And even better, it is understandable. The chapter on solid state physics allowed me to get a B in a graduate level solid state course. The 350 page textbook did not have nearly as much information, and it was impossible to understand. I doubt the book is still in print, but if you can find it, jump on it - it's worth it!
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John
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Okay I admit I didn't read everything, but, how can tiny things act differently to big things? Everything's made of the same stuff! Every object is made of tiny particles. How could the big picture and the things it's made of act differently? That doesn't make sense.
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Particles are subject to forces and effects that "cancel out" in macroscopic environments. There's much much more to it, and it's hard to explain with illustrations and equations. A list of good books on the subject can be found here:
http://clem.mscd.edu/~lindg/books326.htm
The first places to really look if you're interested in understanding the basis of quantum mechanics are the areas of blackbody radiation (the fact that all matter emits the same wavelengths of electromagnetic spectrum at the same temperatures) and the photoelectric effect. They're the least complex and they start to show you how nature of particle/wave duality. After that, start reading about Heisenberg.
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