Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Does the uncertainty principle break symmetry?

  1. Jul 10, 2008 #1
    The classic physics problem example of symmetry breaking is a pencil sitting directly on its tip (pointed down), but it's possible for the pencil to balance on its tip if we reduce the thermal
    fluctuations to zero by cooling it to close zero degree.
    Quantum fluctuations require/mean that after some time no matter that it was ‘perfectly’ balanced it is going to fall over. So the question is that would the pencil, a classical object, fall over due to quantum fluctuations in a thought experiment pioneered by Einstein?
     
  2. jcsd
  3. Jul 10, 2008 #2

    ZapperZ

    User Avatar
    Staff Emeritus
    Science Advisor
    Education Advisor

    If by "HUP" you also includes quantum fluctuation, then of course it can induce some symmetry breaking. Isn't that the whole principle behind quantum phase transition? But this isn't an identical scenario with a pencil sitting on its tip. Besides the realistic problem of setting up the experiment, one should also consider that if the effect is THAT pronounced as to tip over a pencil, then it should also manifest itself in other experiments that are even more sensitive, such as the nanoscale balance that was reported a while back, and all those sub-micron gravitational measurement that came out of the University of Washington. Yet, unless I missed something, they detected no such effects.

    Zz.
     
  4. Jul 10, 2008 #3
    The tip of the pencil - even though appearing very sharp to you - is still orders of magnitude wider than necessary to overcome quantum fluctuations. They are extremely small.
     
  5. Jul 11, 2008 #4
    I don't think the quantum fluctuations are constant in time. Once in a while, there will be a big fluctuation cause the pencil to fall
     
  6. Jul 11, 2008 #5

    ZapperZ

    User Avatar
    Staff Emeritus
    Science Advisor
    Education Advisor

    Then you need to show experimental evidence of the presence of this "big fluctuation", and why it is not detected in all the other, more sensitive, experiments. Without such evidence, you are making unfounded speculation.

    Zz.
     
  7. Jul 11, 2008 #6
    Yes, and once in awhile all the atoms in the pencil will randomly decide to move upward and the pencil will levitate.

    Except for the fact that the odds are one in a number with a whole lot more zeroes than you'll see in the lifetime of the universe.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?



Similar Discussions: Does the uncertainty principle break symmetry?
  1. Symmetry breaking (Replies: 11)

  2. Symmetry Breaking (Replies: 1)

Loading...