Zvi Bern still likes Lagrangians, bless his heart, but in his KITP talk yesterday he talked about (color) Jacobi rules for tree and loop diagrams in certain nice Yang-Mills theories. A three term rule is of course nothing other than the Jacobi rule for Lie algebras in a braided monoidal category. The lower diagram is explicitly discussed in the talk.
Bern's purpose here is to construct a QFT for perturbative gravity, starting with a Yang-Mills theory that manifests a duality between color and kinematics.
3 years ago