Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Disconnected diagram Feynman rules momentum space

  1. Aug 6, 2008 #1

    I wonder if the Feynman rules in momentum space can also be applied to disconnected diagrams. So aussume I have a disconnected Feynman diagram 1 , i.e. the product of two connected Feynman diagrams 2 and 3.
    I can translate my diagrams with the position space Feynman rules to explicit mathematical expressions:

    D=C_2 * C_3

    I can compute the Fourier transforms F(C_2) and F(C_3) by using the Feynman rules in momentum space.

    Now if the FR in moentum space would be applicable for disconnected diagrams, this would mean

    This means the inverse Fourier transform yields
    D= F^-1 [ F(C_2)*F(C_3) ]

    => C_2 * C_3 = F^-1 [ F(C_2)*F(C_3) ]

    How can that be?? This rule is not generally true for Fourier transformations...

    Best regards, Martin
  2. jcsd
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Can you help with the solution or looking for help too?
Draft saved Draft deleted

Similar Discussions: Disconnected diagram Feynman rules momentum space
  1. Feynman Diagrams (Replies: 2)