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The dimensions of elementary particles in quantum physics and string theory

  1. Jul 6, 2012 #1

    T=0

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    I noticed that in quantum physics, an elementary particle has no dimensions, and is point like, but in string theory has one dimension. Why is this?
     
    T=0, Jul 6, 2012
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  3. Jul 6, 2012 #2

    mathman

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    This may sound silly, but basically it is because the theories are different. String theory is looking at things on a much smaller length scale than quantum theory.
     
    mathman, Jul 6, 2012
  4. Jul 7, 2012 #3

    alialice

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    Probably you mean "mass dimension"? In supersymmetric theories, the anticommutator of two susy generators Q is equal to the momentum P, which has mass dimension 1. From here, dimension of Q follows: it is 1/2. Similarly, by imposing that the action has 0 dim, you can find that a scalar field has dimension 1, a spinorial field 3/2, etc.
     
    alialice, Jul 7, 2012
  5. Jul 7, 2012 #4

    T=0

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    Thnx guys, great help.
     
    T=0, Jul 7, 2012
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