# A Correlation functions in position and momentum space

1. Oct 5, 2016

### spaghetti3451

What is the relation between the correlators $\langle 0 | T\phi(x_{1})\phi(x_{2}) | 0 \rangle$ and $\langle 0 | T\phi(p)\phi(x=0) | 0 \rangle$?

I can derive the momentum space Feynman rules for $\langle 0 | T\phi(x_{1})\phi(x_{2}) | 0 \rangle$. Are the momentum space Feynman rules for $\langle 0 | T\phi(p)\phi(x=0) | 0 \rangle$ the same?

2. Oct 11, 2016