feynlag.vertices.yangmills.cubic_couplings¶
- feynlag.vertices.yangmills.cubic_couplings(group, physical=None, U=None)[source]¶
Rotated cubic self-coupling tensor
−g F_ijk.- Parameters:
group – non-abelian gauge group.
physical – physical boson symbols
V_i(default: the group’s own adjoint components,U = 1).U – matrix with
A^a = Σ_i U[a,i] V_i.
- Returns:
dict
{(V_i, V_j, V_k): −g·F_ijk}(only non-zero, all orderings — the tensor is totally antisymmetric under simultaneous exchange). Lorentz structure: the universal YMVVVcatalog entry.