FunctionalDiagrams logo: the exchange vacuum diagram

FunctionalDiagrams

Feynman diagrams from functional derivatives — a Mathematica package for perturbation theory, effective actions and many-body physics

Write a generating functional and an interaction: the package takes the functional derivatives, with the fermion signs and the symmetry factors, and returns the Feynman diagrams, which it can classify, check against exact equations, evaluate in a few common cases and draw as in the textbooks.

Demo of FunctionalDiagrams: diagrams generated by functional derivatives, then the Bethe-Salpeter and parquet equations and Hedin's equations of the electron gas