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Schwinger-Dyson equation help

  1. Aug 22, 2008 #1
    in Pages 307-308 of Peskin and Schröeder we find

    [tex] \delta S (< \Omega | T( \phi (x1) \phi(x2)..... \phi (xN) | \Omega >)= -\sum_{n=1}^{N}< \Omega | T( \phi (x1) \phi(x2)..i\delta (x-xi)... \phi (xN) | \Omega > [/tex]

    they are the Schwinger Dyson equation for the correlation function , my question is , how could i use Wick's theorem to compute the quantity

    [tex] < \Omega | T( \phi (x1) \phi(x2)..i\delta (x-xi)... \phi (xN) | \Omega > [/tex] for every 'i'

    here [tex] \delta S [/tex] is the functional derivative of the action 'S'
  2. jcsd
  3. Aug 26, 2008 #2


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    Your first equation does not appear in P&S, and I don't understand what you mean by it. Referring to eq.(9.86) on p.307 of P&S, the delta function can be pulled outside the correlation function (since it is just a number, not an operator). Then you are left with a standard correlation function.
  4. Feb 25, 2011 #3
    thatis easy , pull the delta functions out of the correlator and then apply wick's theorm by writing out Green functions"feynman's propagators"
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