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Why is a phonon a boson?

  1. Nov 6, 2005 #1
    I have searched in a lot of books and online resources, and none of them shed any light on why phonons are bosons.

    Can someone here help me?
  2. jcsd
  3. Nov 6, 2005 #2


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    Because it carries a spin of zero.

  4. Nov 6, 2005 #3


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    Phonons are the quantization of vibrations in a solid. Since vibrations are additive, that is, you can double and triple a (small) vibration and have still be vibration but twice or three times as strong, phonons must satisfy bose statistics. That is, they do not satisfy the Pauli exclusion principle. So they're bosons.

  5. Nov 12, 2005 #4
    Phonons are bosons because of their spin 0 value.

    A better question would have been : why do phonons have spin 0 ?

    Their is a really easy answer if you are familiar with group theory and symmetries.


  6. Nov 12, 2009 #5
    I was wondering why phonons should have spin zero, too. After all, the quantized system looks just like QED, only with more (!) polarizations, so even in the simplest acoustic case we have one longitudinal and two transversal modes. This looks like spin 1.

    On the other hand, spin is defined by the Lorentz-group, i.e. the behavior under rotations, which is not exactly usable in a lattice. So my guess is that this reduction of the full rotational group to the discrete rotation group causes the concept of spin to break down.

    Is this about right? Books are amazingly useless when it comes to phonon spin...

  7. Nov 17, 2009 #6
    What is the group theory reason for this?
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