Home / Topics / Particle Physics & Cosmology
Feynman diagrams
Advanced
Pictorial representation of particle interactions.
Lines and vertices diagrams represent particle interactions; each diagram corresponds to a term in the perturbation series for the amplitude. Time runs horizontally, wavy lines are bosons.
Electron scattering by exchange of a photon.
Not literal paths.
In more detail
Feynman diagrams are pictorial representations of particle interactions, showing particles as lines and vertices as interactions. Each diagram corresponds to a term in a calculation.
Real-world uses
- Feynman diagrams are used to calculate scattering and decay rates.
- They help physicists communicate and check calculations.
- Particle physicists draw Feynman diagrams to calculate the probability of processes such as electron scattering.
Open the interactive lesson, with simulation and quiz →
Frequently asked questions
Are the lines real paths?
No, they are a bookkeeping tool for contributions to probability amplitudes.
Who invented them?
Richard Feynman, in the 1940s.
Are Feynman diagrams literal pictures?
No. They are a bookkeeping device for calculating amplitudes, not pictures of particles moving along paths.
Related topics in Particle Physics & Cosmology
Weak interaction · Electroweak unification · Conservation laws in particles · Particle accelerators · Large Hadron Collider · Particle detectors