Why is the Feynman diagram for the following nasty 10 point Green's function so simple: I mean it only has two external points, one vertex, and one loop:(adsbygoogle = window.adsbygoogle || []).push({});

Here is the offending function:

[tex]\int d^4y_1 d^4y_2 <0|T[\phi (x_1) \phi (x_2) \phi^4 (y_1) \phi^4 (y_2)]|0>[/tex]

which I am assuming is simply equal to:

[tex]\int d^4y_1 d^4y_2 <0|T[\phi (x_1) \phi (x_2) \phi (y_1) \phi (y_1)\phi (y_1) \phi (y_1) \phi (y_2)\phi (y_2) \phi (y_2) \phi (y_2)]|0>[/tex]?

I mean this expression is very complicated - lets see:

[tex]F(\phi (x_1) \phi (x_2))F(\phi (y_1) \phi (y_1) ) F(\phi (y_1) \phi (y_1) ) F(\phi (y_2) \phi (y_2))F(\phi (y_2) \phi (y_2)) +

F(\phi (x_1) \phi (y_1))F( \phi (x_2) \phi (y_1))F(\phi (y_1) \phi (y_1) ) F(\phi (y_2) \phi (y_2))F(\phi (y_2) \phi (y_2)) +.... [/tex]

(where F( ) is a contraction of operators).

Is there any way to simply this horrendous expression?

Thanks...

**Physics Forums - The Fusion of Science and Community**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Applying Wick's Theorem

Can you offer guidance or do you also need help?

Draft saved
Draft deleted

Loading...

Similar Threads - Applying Wick's Theorem | Date |
---|---|

I Virial theorem as applied to hydrogen atom | Apr 11, 2017 |

**Physics Forums - The Fusion of Science and Community**