Correlation function (quantum field theory): Difference between revisions

Revision as of 21:22, 18 January 2022

Revision as of 16:13, 10 February 2022

Line 72:

</math>

Here the particles in the initial state <math>|i\rangle</math> have a <math>-i</math> sign in the exponential, while the particles in the final state <math>|f\rangle</math> have a <math>+i</math>. All terms in the Feynman diagram expansion of the correlation function will have one propagator for each external leg, that is a propagators with one end at <math>x_i</math> and the other at some internal vertex <math>x</math>. The significance of this formula becomes clear after the application of the [[Klein-GordonKlein–Gordon equation|Klein-GordonKlein–Gordon]] operators to these external legs using

:<math>