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Is a mobius strip spin 1/2 object?

  1. Mar 4, 2004 #1
    Remember Phiysicist always say electron has a spin of 1/2; I can't remember how it was derived?

    But I noticed a mobius strip exihibit interesting attribute. Can we consider a mobius strip a spin 1/2 object?
  2. jcsd
  3. Mar 4, 2004 #2


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    Electron spin 1/2 is an intrinsic quantum theory property. A mobius strip is a twisted piece of paper - it has nothing to do with quantum teory.
  4. Mar 4, 2004 #3
    Well, a mobius strip is a non-orientable manifold, not a "twisted piece of paper". The obvious "connection" between the orientation of a unit normal vector on a mobius strip and 2-spinors (the representations of angular momentum states) is that they both require rotations of [tex]4\pi[/tex] to regain their original orientation.

    So, mobius strip normal orientation and spinor rotations aren't that different.

    Shouldn't this discussion be in the Quantum Physics subforum?
    Last edited: Mar 4, 2004
  5. Mar 4, 2004 #4
    As has been mentioned by many people before us, the entire spin-1/2 business falls out of relativistic Q.M.

    The Mobius strip property is an analogy that is used in discussions of spin, at least pedagogically - I remember it being mentioned in undergraduate Q.M., as well as in the ever so delightful Principles of Magnetic Resonance by C.P. Slichter. It's intended to serve as a useful first step to understanding rotations.
  6. Mar 4, 2004 #5
    I thought my high school Physics teacher already showed us the spin 1/2 of electrons by examining its angular momentum against its light absortion spectrum.

    That's why I thought this could be put in here as all it involves is rotation and angular momentum.

    What you told me now is that the electrons' spins are more likely a QM quantity not related to a classical anugular rotation. I am not familiar with the modern QM at all. But didn't this spin 1/2 come originally from applying classical theory to the spectrum?
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