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The uncertainity principle, a new take?

  1. Jan 5, 2013 #1
    http://www.livescience.com/18567-wac...principle.html [Broken]

    are these once again bold claims?

    they are saying the uncertainty principle isnt just in measurement but in the very nature of the quantum. It seems to be bold claims and not reperated anywhere on any other sites and certainly doesnt seem to be being touted as a big breakthrough with convincing evidence.

    opinons please...
    Last edited by a moderator: May 6, 2017
  2. jcsd
  3. Jan 5, 2013 #2


    Staff: Mentor

    Cant say your link is broken.

    Is it this link?


    Having read the article it seems legit as they are posting a paper in the Physical Review Letters. It doesn't seem such a bold claim only that with more careful measurement you can get better results while still being limited by the Uncertainty principle.

    Its like saying that PI to 10 digits is very accurate but with more time on a computer you can get an even better value/approximation for PI while not upsetting any math that relies on its value.
    Last edited: Jan 5, 2013
  4. Jan 5, 2013 #3


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    Yes, that is correct.
  5. Jan 5, 2013 #4


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    See above. The statement is correct. However it is not a bold claim, but simply the standard description. The observer measurement is a misunderstanding.
    Last edited by a moderator: May 6, 2017
  6. Jan 5, 2013 #5
  7. Jan 5, 2013 #6
    your opinon, dont just say something is correct when its opinon! if it was fact this article would not be making a big deal out of something we knew, but it is...
  8. Jan 5, 2013 #7


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    No, I was not offering that statement as an opinion, it is standard physics and has been for quite a long time.
  9. Jan 5, 2013 #8
    well in certain interpretations the world isnt quantum like so it is your opinon, you have not even read the article so how do you even know that its true!
  10. Jan 5, 2013 #9
    didnt expect a reply lol!
  11. Jan 5, 2013 #10


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    I read the article before my last post. You seem to have misunderstood it.

    EDIT: reread post #2

    2nd edit: nuts ... is that still pointing to the wrong site? I read the one you posted to on the second post of yours and THAT is the one I think you did not understand.
  12. Jan 5, 2013 #11
    it says nature is actually confirmed as quantum like at the lowest level. It is not. It is subject to interpretation i.e bohn and other determinstic theories of QM
  13. Jan 5, 2013 #12
    well am I right or missing something? is this unrelated to the experiement in question,

    help please people....
  14. Jan 5, 2013 #13
    Well, this is not an easy subject, and one has to be careful with one's wordings here! :-) There are no interpretations of quantum mechanics that are not "quantum like". All interpretations yields the same predictions for any observable quantity. Otherwise they would simply be wrong when compared with experiments.

    It is true that some hidden variable-interpretations (like De Broglie-Bohm) allow particles to have well-defined locations at all times. But they are still quantum, they just hide the weirdness somewhere else. (Explicitly non-local guiding pilot-waves for example.)

    The uncertainty principle is about expectationvalues of observables, and is therefor independent of which QM-interpretation you believe in. That the uncertainty principle is a fundamental limit of nature and not a limit of measurement technology is well established, and not a matter of personal opinion.

    The standard Heisenberg example of a photon disturbing an electron is just an example. It is not the motivation behind the uncertainty principle. As they point out in the article you quote, this example has mislead many people. And their experimental data reinforces the full quantum mechanical calculation, again saying that this is not any bald claim (just a nice confirmation of the true principle).

    I think the best way to understand the fundamental uncertainty principle is to think of the double-slit electron interference experiment. We know that any measurement of which path the electron takes destroys the interferencepattern. Also, in the two different paths the electron is deflected a slightly different angle by the wall. So the electron have to transfer different amount of momenta to the wall depending on which slit it goes through. So in principle one could find out which way the electron took by measuring the recoil momenta on the wall with high enough precision. (The wall might for example be very small and thin and suspended on low-friction wheels...) Doing the calculations, it turns out that the precision needed to gain the which-way information is precisely below the Heisenberg limit. Hence, if there was any way in principle to gain this information, we could not see any interference pattern!

    In this way we see that the uncertainty principle have to be a fundamental property of nature, regardless which theory we use to describe it.
  15. Jan 5, 2013 #14


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