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Witten Index

  1. Feb 6, 2008 #1
    Does anyone know where I can find a brief and useful description of the Witten index? The Wikipedia entry isn't bad, but didn't give me a real good understanding of it.

    (I have ascertained that for SU(N), the Witten index is N. Does this mean that SU(N) has N supersymmetric vacua, or that SU(N) has more than zero supersymmetric vacua?)
  2. jcsd
  3. Feb 7, 2008 #2


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    Theres probably a decent discussion in most textbooks on supersymmetry. Weinberg has a few pages devoted to it (pg 250-). For your purposes, its just Tr(-1)^F where F is the fermion number.

    Its primary use is to figure out whether or not supersymmetry remains unbroken beyond perturbation theory.

    If you hate reading Weinberg, maybe track down the original paper. I'd imagine Witten probably has a more than readable gist
  4. Feb 7, 2008 #3
    I'm affraid you're right. I was trying to avoid walking to the library (we don't have a subscription to Science Direct), but I fear it is unavoidable.

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