Knotty Gauge Theory

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.