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Self-energy for two correlators

  1. Sep 10, 2015 #1
    Imagine I want to calculate the INTERACTING single particle Green function in a model:

    \begin{eqnarray}
    G(t-t')=\langle Td(t)d^{\dagger}(t')\rangle
    \end{eqnarray}

    We know from Dyson equation that this is:\\
    \begin{eqnarray}
    G=G_{0} + G_{0}\Sigma G
    \end{eqnarray}
    Where $\Sigma$ is the self-energy. My question is, if we want to calculate the correlator :\\
    \begin{eqnarray}
    g(t-t')=\langle Td(t)^{\dagger}d(t')\rangle
    \end{eqnarray}
    Does the self-energy $\Sigma$ change for this correlator? In my intuition it shouldnt, but maybe I am wrong... Thanks!
     
  2. jcsd
  3. Sep 10, 2015 #2
    Oh and by the way I forgot, does Dyson equation apply to this correlator as well ($g(t-t')$)? (Even not being the definition of a Green function, can this infinite series be hold in a correlator like that when we do perturbation theory? )
     
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