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Help with Spin.

  1. Feb 24, 2010 #1
    Hi, all.

    Would anyone suggest your own idea about what actually spin it is? I can not form an image

    in my head about spin...

    Spin is vector, can be 1/2 can be 1, and if say it is 1/2, then Spin's Z component can be -1/2 or +1/2 ...??!! and the magnitude of spin vector is:

    |S| = sqrt(S(S+1)) ???!! how to really really understand it?

    Please leave your own idea, it will be great helps!

    Thanks in advance!
  2. jcsd
  3. Feb 24, 2010 #2
    It may help to know that spin is a conserved quantity, just as energy or momentum are conserved quantities. Call this, "conservation of spin."
  4. Feb 24, 2010 #3
    Spin is not understandable,just as many other quantum concepts,or as 4D space which cannot be imagined.
    If you try hard to 'understand' it ,you will get yourself in trouble,since human imagination is limited to everyday stuff.Learn it mathematically.
  5. Feb 24, 2010 #4
    ...But I can understand--in fact visualize--Heisenberg's Uncertainty Principle in action though!...
    What was that maxim of Einstein's? Oh yeah. "Imagination is more important than knowledge."
  6. Feb 24, 2010 #5
    Visualization is easy.Just regard spin as spin, like the earth spinning around.

    Einstein is a great scientist,but he is also famous for his dislike of quantum theory.You shouldn't cite his words when discussing quantum theory.
    Otherwise I will cite " God does not play dice with the universe!"
  7. Feb 24, 2010 #6
    Lulz, that last sentence of yours it's like... touche!
    Anyways. Remember John Bell's inequalities [and their consequent violations] came most unexpectantly, so EPR was always considered more or less valid, up until Aspect conducted his great experiment (the Alain Aspect experiment) that verified entanglement and cast serious doubt on the concept of the hidden variable hypotheses.
    I still believe Einstein has been right all along--that is to say that quantum theory is an incomplet one, just waiting for someone to come along with the Brilliant Idea which will explain the strange phonomena of entanglement...
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