To understand how one electron influences another, using Feynman diagrams, you have to imagine that the electrons, as they move through space and evolve in time, exchange a photon, here labeled ...

The efforts of Dyson worked well, and the Feynman diagram spread, greatly affecting modern theoretical physics. However, as time goes on, it also turns out that Feinman diagrams have limitations.

To understand how one electron influences another, using Feynman diagrams, you have to imagine that the electrons, as they move through space and evolve in time, exchange a photon, here labeled ...