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Thread: Quantum Mechanics suck!!!

  1. #1 Quantum Mechanics suck!!! 
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    I was watching a documentary the other day, and it was talking about an idea I had been thinking about for a few months. The ability to predict the future based on how things have gone in the past. For instance, I roll a ball at you. What will happen? It will go to you ofcourse. Well the same should be said about the planets' orbits and everything in our daily lives.

    Well this documentary started talking about this idea and it said that Einstein thought this too, which got me all excited because I thought I had thought of something brilliant (though already known to the world) on my own. Then it interrupted it and said that I was actually a fool becasue quantum theory dictates, that even though I roll the ball to you, it may actually spontaneously dissintegrate and re appear on mars... wow that was dumb. That just screwed up my whole train of thought.

    YOU SUCK Quantum Mechanics!!!!
    (No question here, just venting)


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    thats how quantum mechanic is and allways have and allways will be. a determenistic world dont exist in the world of physics anymore. BUt of course the chance that ball reaphhering on mars or even disintergrating is very unlikly, so unlikly it might just happen before the last blackhole dies, within the human races exists, no

    quantum mechanic is acctualy brilliant, all its predictions have been confirmed and shown repeadedly, hows it spelled?. in normal world its almost determenistic, almos


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  4. #3  
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    I enjoy quantum mechanics for no other reason than I can use it to annoy determinist and poke holes in deterministic thinking.
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    quantum mechanics and special relativity are really cool man, yeah, superstring theory... both are interesting...
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    Quote Originally Posted by Phanixis
    I enjoy quantum mechanics for no other reason than I can use it to annoy determinist and poke holes in deterministic thinking.
    Well QM doesn't necessarily spell doom for the determinist, so I hear. Decoherence in QM provides a mechanism for what appears to be wavefunction collagpse in the Copenhagen interpretation. Maybe somebody more well-versed in QM can explain it better -
    Decoherence is a place to start though
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    Quote Originally Posted by Neutrino
    Quote Originally Posted by Phanixis
    I enjoy quantum mechanics for no other reason than I can use it to annoy determinist and poke holes in deterministic thinking.
    Well QM doesn't necessarily spell doom for the determinist, so I hear. Decoherence in QM provides a mechanism for what appears to be wavefunction collagpse in the Copenhagen interpretation. Maybe somebody more well-versed in QM can explain it better -
    Decoherence is a place to start though
    I am afraid to burst your bubble but that is not what decoherence is all about. Look, there will always be those who stubbornly refuse to let go of determinism in physics like David Bohm. But the Bell inequality experiments put the nail in the coffin. I should point out that it is not the end of determinism really but only the end of determinism in physics, the end of physical determinism. In other words, you have to give up on one of two things: the completeness of the physical description of reality or determinism. You could conceivably still uphold determinism if you accept the the existence of aspects of reality which do not fit within the local model of reality that is the presumption of physics. If you accept some mysterious nonlocal force outside the description of physics you can still uphold determinism. Personally I do accept the existence of aspects of reality outside the description of reality in physics, but I still reject determinism as incompatable with my experience of reality. So there is actually a third option of giving up both the completeness of physics and determinism.

    Decoherence is an attempt to understand the process which has been refered to as wave collapse or measurement. I have made similar attempts using the ideas of amplification, feed back and chaotic dynamics. It is natural thing to try to understand how these events actually occur, for the wave collapse is more a failure of the current mathematics of quantum mechanics to model these events, than any kind of description of reality. The ambiguity that results is the source of some confusion. For example in the thought experiment known as "Schrodinger's cat" quantum mechanics seems to suggest that you have a cat which is both dead and alive at the same time, until you look in the box. Nobody really believes this, except maybe idealists who like the idea of the mind being the ultimate reality. But most physicists assume that something prevents quantum indeterminacy from existing on a macroscopic level of reality and explorations into the process of the so called "wave collapse" promises to explain why.
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    Well - all I can say is what I've read by people who know way more about it than I do. When you get conflicting viewpoints from people who are above your head, who knows what to think.
    This is from cavediver over at evcforum.net - I've definitely come to trust his physics knowledge
    Not knowing the moment of radioactive decay or the spin of an electron is only a case of unknowable from the POV of random "collapse" of the WF. There is no collapse in decoherence, just interaction between the WFs of the object under scrutiny, its environment, and the observer, which successively narrow the WF until we call it a collapse. This is deterministic, essentially obeying the SE just as in normal QM.
    and
    THERE IS NO COLLAPSE IN DECOHERENCE. It is all deterministic. That is the point...

    Now decogerence is not cut and dry, but it is a very respectable possibility. Thus we cannot claim with certainty that there are
    uncaused occurances.
    and
    The "collapse" portion of the CI is a bugbear, a cludge that does not really fit. This has been recognised since its inception. In decoherence and similar mechanisms, there is no collapse. What we think of collapse is just the observable's wavefunction becoming more and more sharply peaked (i.e. approaching what we would call a definite state - decohering) through interaction with the wavefunctions of its environment and that of the observing apparatus. We think that gravitons play a large role in this decoherence.

    As there is no collapse, there is just deterministic evolution of the wavefunctions. And hence there are no uncaused actions.
    Are you saying he's wrong, or am I missing something? If you think he's wrong, and had the interest, I think it would be fascinating to see you guys interact with each other over there on that issue - it'd be a great chance for laymen like myself to learn a little something.

    Personally I don't have a clue who's right - it was always my understanding that QM was inherently indeterministic but reading his thoughts on the matter have changed my mind - or at least opened it to the possibility of determinism

    Here's the thread if you were at all interested in gathering the context of my quotes, though a new thread would probably be required to pursue that course of discussion - thread
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    determenism is dead in QM. its random there
    I am zelos. Destroyer of planets, exterminator of life, conquerer of worlds. I have come to rule this uiniverse. And there is nothing u pathetic biengs can do to stop me

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    Quote Originally Posted by Neutrino
    THERE IS NO COLLAPSE IN DECOHERENCE. It is all deterministic. That is the point...

    Now decogerence is not cut and dry, but it is a very respectable possibility. Thus we cannot claim with certainty that there are
    uncaused occurances.
    and
    The "collapse" portion of the CI is a bugbear, a cludge that does not really fit. This has been recognised since its inception. In decoherence and similar mechanisms, there is no collapse. What we think of collapse is just the observable's wavefunction becoming more and more sharply peaked (i.e. approaching what we would call a definite state - decohering) through interaction with the wavefunctions of its environment and that of the observing apparatus. We think that gravitons play a large role in this decoherence.

    As there is no collapse, there is just deterministic evolution of the wavefunctions. And hence there are no uncaused actions.
    Are you saying he's wrong, or am I missing something? If you think he's wrong, and had the interest, I think it would be fascinating to see you guys interact with each other over there on that issue - it'd be a great chance for laymen like myself to learn a little something.
    I can understand how, being determined to save determinism, he may have come to this conclusion but it doesn't make any sense in terms of the basic physics. He cannot change the probabilistic nature of quantum mechanics and he cannot overturn the results of the Bell inequality experiments. This kind of determination to prove ones point of view reminds me of the so called science of Creationism.

    Well I do not know who cavediver is but you have my name so you can find out exactly who and what I am. That he is one of the diehards I mentioned who will grasp at any straw to justify determinism is obvious. But frankly, what you quote from cavediver is simple minded rhetoric. It is true that the wave collapse or measurement represents the events in quantum mechanics where determinism breaks down, but the idea that the unpredictability in quantum mechanics depends on there being a wave collapse in the theory is absurd. The measurement event, however it is modeled mathematically, is not deterministic, the only way around this, I have already explained. The physics behind this is solid and unambiguous.

    I have already explained that the wave collapse is a hole in the theory (cludge is a weird way of putting it) that should be explained, but filling in this hole has absolutely nothing to do with determinism. But don't take my word for it, read some of these reports. I explained what decoherence was trying to do, these reports say that it fails to do even that. What you will not find in these reports is any mention of determinism, predictability or overturning the Bell experiment results, and that is because it has nothing to do with it. It is a little hard to see how you can mathematically model this failure of determinism mathematically without some kind of discontinuity like the wave collapse. We may never be able to mathematically model the whole process without any such discontinuity, BUT the eliminating the failure of determinism is not a possible result of this effort. It is perfectly obvious that any continuous mathematical model that fails to model the failure of determinism will fail to model quantum mechanics at all. This may be why decoherence has ultimately failed to resolve the measurement problem and I think that rather than eliminating the discontinuity it has simply pushed it out of sight. I hold out hope that chaotic dynamics may provide some clue to solving the measurement problem by giving some answers to why the measurement is unpredictable.

    This is particularly readable it is a report by a student trying to qualify as a PHD candidate.
    http://www.physics.drexel.edu/~tim/open/main/

    Wikipedia is more detailed and advanced.
    http://en.wikipedia.org/wiki/Wavefunction_collapse
    http://en.wikipedia.org/wiki/Quantum_decoherence

    If you want to read something by non-physicists that may explain where this guy may have found support for his ideas, you can read this.
    http://www.geneticengineering.org/ev...cfaddenc9.html

    The point is that physics does not box you into determinism. As a non-physicist you are free to make your own choices, and believe in determinism or not as you choose. Frankly I would use your own judgement in this and not just swallow what someone is trying to sell you. You have as much access to the raw data of the human experience as anyone else.
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    Thanks for the response mitchell.
    The point is that physics does not box you into determinism. As a non-physicist you are free to make your own choices, and believe in determinism or not as you choose. Frankly I would use your own judgement in this and not just swallow what someone is trying to sell you. You have as much access to the raw data of the human experience as anyone else.
    The problem is, we're all at the mercy of what physicists tell us when it comes to understanding these things. Even the most interested layman is still just that and without an understanding of all the mathematics involved and having access to (and ability to understand) the research involved, it still just boils down to trusting what we hear from the experts.
    I think he'd agree that physics doesn't box you into determinism, but I think he'd also say that it doesn't remove the possibility of determinism either.
    One or the other of you needs to go to the other board, I'm sure there's more than just me who'd like to hear a discussion on this :P
    I'll check out those links now, thanks for them.
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    Quote Originally Posted by Neutrino
    The problem is, we're all at the mercy of what physicists tell us when it comes to understanding these things. Even the most interested layman is still just that and without an understanding of all the mathematics involved and having access to (and ability to understand) the research involved, it still just boils down to trusting what we hear from the experts.
    Only about what physics says. And the overwhelming evidence is that physics not only does not decide the issue but that you must choose determinism or physical materialism or neither.

    Quote Originally Posted by Neutrino
    I think he'd agree that physics doesn't box you into determinism, but I think he'd also say that it doesn't remove the possibility of determinism either.
    I don't think so. Because that is exactly what I am saying. The failure of determinism in physics only means that physics cannot dictate this issue one way or the other. The whole idea of stubbornly saving determinism in physics is so that you can weigh science in on the determinism side of the argument in a rather overwhelming manner as it was during the nineteenth and eighteenth centuries.

    Quote Originally Posted by Neutrino
    One or the other of you needs to go to the other board, I'm sure there's more than just me who'd like to hear a discussion on this :P
    I'll check out those links now, thanks for them.
    I am not as optimistic that the discussion between us would be any more fruitful than your report of what he says. My responses here is all that I can say. I am not impressed by what you quote of him such that I would be motivated to make any such effort. I have heard such stubborn defenses of determinism before and it is a waste of time. It is not my mission in life to hunt down everyone whom I think is wrong and try to convince them of their error. They are free to believe as they choose.
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    I have heard such stubborn defenses of determinism before and it is a waste of time. It is not my mission in life to hunt down everyone whom I think is wrong and try to convince them of their error. They are free to believe as they choose.
    This may be the case, and I hate to keep talking about the guy when he's not around to read it, but this isn't just some yahoo who prefers determinism and will cling to any hope for it. He knows what he's talking about though I realize my word isn't much to go on. His posts weren't made in an attempt to argue for determinism, but rather to caution those were who claiming that QM necessitates indeterminism. I need to quit speaking on this though as I really don't want to misrepresent anything he's said. But the link to the thread (and board) is there for any interested.
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    Quote Originally Posted by Neutrino
    This may be the case, and I hate to keep talking about the guy when he's not around to read it, but this isn't just some yahoo who prefers determinism and will cling to any hope for it. He knows what he's talking about though I realize my word isn't much to go on. His posts weren't made in an attempt to argue for determinism, but rather to caution those were who claiming that QM necessitates indeterminism. I need to quit speaking on this though as I really don't want to misrepresent anything he's said. But the link to the thread (and board) is there for any interested.
    I have read the thread and I understand your difficulty. He claims to be a teacher and I do not doubt it, but there is little else we know of him, not that it matters. You see there are very well educated physicists who have a real hard time accepting the conclusions of quantum mechanics. Einstein was one of them. Stubborn holdouts like him are the reasons why the physics community is not 100% behind the Copenhagen Interpretation (which the vast majority of physicists simply call quantum mechanics).

    The many worlds interpretation is the only significant competing interpretation and I think that this interpretation is 100% equivalent to CI. As far as the question of the kind of determinism, we have been talking about, is concerned, the choice between CI or MWI makes no effective difference. In fact I think that the MWI is exactly where cavediver's idea decoherence leads, which is no great accomplishment at all. MWI is old news. We already know that you can preserve determinism and make the mathematical model of measurement continuous by saying that a superpostion of worlds is generated where all the possible results occur in all these possible worlds. But this just hides the discontinuity from view in this unobservable, unmeasurable, totally philosophical divergence of different worlds from each other, not to mention completely trashing all the ideas of conservation of energy. Furthermore it only saves mathematical determinism not philosophical determinsim which is only concerned with what happens in our own world, and in this world, things that we call events remain without cause. Personally, I would call these other worlds in the MWI unrealized possibilities and stick to what is observable as the only meaningful physical reality. I consider the MWI just one of the ways that you can go beyond the accepted idea of local reality in physics in order to preserve determinism.

    Percy is doing a good job despite his lack of confidence (due to his admitted lower level of education). And cavediver is not answering the obvious questions, he is dodging. His call for caution after the solid victories of the Copenhagen Interpretation are quite hollow. If you want the judgement of the physics community on this issue you must go with the vast majority which is definitely not cavediver's point of view. Just ask him that and he will have to admit it.
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    am a collage student and my studying dont have any thing to do with quantum physics

    but i have a big pation for it

    i study it by my self and if i have any question i ask one of the physics proff. in the university

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  16. #15  
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    lol im a sophomore =P is anyone in here younger then me ?o.O
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  17. #16  
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    Quote Originally Posted by iLOVEscience
    lol im a sophomore =P is anyone in here younger then me ?o.O
    how old are you and what is a sophomore?
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    Quote Originally Posted by Phanixis
    I enjoy quantum mechanics for no other reason than I can use it to annoy determinist and poke holes in deterministic thinking.
    Err, well, see... if God does exist (in the traditional sense), then the probabilities could just be things made to look like probabilities that God has complete control over. HA! I can argue against anything. Even my own beliefs. :-D
    <i8b4uUnderground> d-_-b
    <BonyNoMore> how u make that inverted b?
    <BonyNoMore> wait
    <BonyNoMore> never mind
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