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Where does the electron go during a quantum jump?

  1. Aug 9, 2012 #1
    Hi, my first post here so be gentle with me :)

    Firstly I have no background in physics other than watching the sky at night so any complex mathematical explanations will be lost on me, I'm just looking for an intuitive way to understand what is happening in a system that's quantized. All my attempts at figuring it out end up in contradiction.

    If an electron can only exist in discrete orbits then how does it actually "get" from orbit A to orbit B, I assume that if it can only exist in certain orbits then it cannot be moving from one orbit to the next through space I also assume there must be some sort of delay between jumps or it would violate the limitations of speed c.

    If my assumptions are correct and it cannot physically traverse the gap to a different orbit and it cannot jump instantly then it must vanish for some length of time and then re-materialise.

    Is it absorbed by the vacuum and then and then re-emitted at a different location?
    If it does vanish does that mean that for a tiny instant the atom becomes a different element?
    Or is it just that this phenomenon cannot be expressed in in any other way than mathematics.

    Any help putting me on the right track appreciated.
     
  2. jcsd
  3. Aug 9, 2012 #2

    Nugatory

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    Yes. The electron isn't really a tiny solid object that jumps from one orbit to another; that's just a way of visualizing what the math says about the possible energy levels of the atom.
     
    Last edited: Aug 9, 2012
  4. Aug 9, 2012 #3

    bhobba

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    Quantum Mechanics is a theory about the outcomes of observations. What it is doing between observations is not something the theory really is on about. The quantum state is basically a codification of the probabilities of what the outcome would be if you set up things to observe it in some way. In interpretations that make use of decohrence (eg decoherent histories) they call such things a pre-probability meaning it can not be actualized until it interacts with some observational apparatus and decoherence takes effect.

    Thanks
    Bill
     
    Last edited: Aug 9, 2012
  5. Aug 9, 2012 #4
    Thank you Nugatory & bhobba for your help.

    Am I right in thinking from your explanations that the quantum jump isn't an experimentally observed phenomenon and that its just mathematical concept?
     
  6. Aug 9, 2012 #5

    bhobba

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    I think its better to view it as something the theory is silent about. In predicting that only certain observations are possible what it is saying is when it makes a quantum jump is it changes from one observational outcome to another - what it is between observations is not part of the theory.

    Just as an aside it is often said Einstein did not agree QM was correct. That is not true - he believed it was incomplete not incorrect. For example at one time a textbook on QM written by David Bohm was popular. Einstein wrote a forward to it commending its ideas to all physicists - discussions with Einstein on that book is what sparked Bohms interest in an re-discovery of Bohmian Mechanics - although Einstein wasn't a fan. Einstein thought a theory based only on the outcomes of observations and ascribing no underlying reality to what was being observed other than something that codifies the probabilities of what an observation would yield could not be correct - it must be doing something when not observed - reality out there exists independent of observation. The view engendered by QM is so counter intuitive that even the greats like Einstein had difficulty with it - don't be surprised if you do as well - its only to be expected. Einstein may be right - trouble is no one has ever been able to come up with an experimentally verifiable way to prove Einstein was correct. Personally I have zero problems with such a view of the world, but then again I am a math type dude and the beauty of QM at the mathematical level is sublime - so sublime I believe it is correct and our intuition of the world wrong.

    Thanks
    Bill
     
    Last edited: Aug 9, 2012
  7. Aug 9, 2012 #6
    lol I'm glad you pointed out that I'm not the only one having difficulty grasping all the concepts, its the only thing that gives me any comfort :)

    As a mathematician does it not disturb you that nature is capable of generating randomness, an ability that no computer will ever possess no matter how powerful it is. I have read about Einstein's concerns and the "hidden variables", deep down I believe that the laws of nature essentially has a seed for randomness and if we knew the formula everything that appears random would in fact be working like clockwork.

    Its easy to calculate probabilities but its impossible for mathematics to generate random numbers, only pseudo random strings. If nature is truly capable of generating a random number then its simply mind blowing.
     
  8. Aug 9, 2012 #7

    bhobba

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    True randomness from a deterministic process is impossible. I would turn the argument on its head and say unless nature is truly random at a fundamental level how do you expect to ultimately account for anything? If everything has a definite cause then you have the infinite regress argument as to what the ultimate cause of anything is. If at some point you cant say all we can predict is probabilities then you are in a real pickle.

    I am not a philosophical type but the interesting thing I find about philosophical arguments is they never seem to actually resolve anything - not like science which bases its essence on skepticism, but actually takes a position based on experiment until something is contradicted by experiment then its again up for grabs.

    Again as an aside I find it very interesting that due to something called Gleasons Theorem only probabilistic models are possible with a theory based on observables encoded in an invariant way (by which I mean basis independent) on vector spaces. It was not put in at the start but that's what pops out - but it will take me too far afield to go deeply into it. But do do a Google on Gleasons Theorem.

    Thanks
    Bill
     
    Last edited: Aug 9, 2012
  9. Aug 9, 2012 #8

    DrChinese

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    Are you familiar with Bell's Theorem? It addresses this point. In essence, it states that for this kind of realism to operate, there must be non-local action at a distance. That is the Bohmian program. Alternately, you can reject the notion of clockwork-like realism and you can maintain locality (i.e. the speed of light c is the limit for propagation for causal effects).

    In other words, there are several possible interpretations of QM.
     
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