Portions of this entry contributed by Bhuvanesh Bhatt
In order to visualize and describe quantum electrodynamical interactions, physicist Richard P. Feynman introduced an ingenious schematic form of drawing now called a Feynman diagram. In such a diagram, all particles are represented by lines, with straight lines representing fermions and wavy lines representing bosons (except for the Higgs boson, which is usually represented by a dashed line, and gluons, which are usually represented by loops).
Particles entering or leaving a Feynman diagram correspond to real particles, while intermediate lines represent virtual particles. Real particles must satisfy the energy-momentum relation .
A Feynman diagram can be transcribed to a complex amplitude using the Feynman rules.