ToLightConeComponents
ToLightConeComponents[expr, n, nb]
rewrites all Dirac matrices, scalar products, 4-vectors and metric tensors in terms of their component along the lightcone directions n
and nb
Using the option NotMomentum
one can specify that quantities containing the listed 4-momenta should be left untouched.
See also
Overview, ExpandScalarProduct, LightConePerpendicularComponent.
Examples
ToLightConeComponents[SP[a, b], n, nb]
21(a⋅nb)(b⋅n)+21(a⋅n)(b⋅nb)+a⋅b⊥
ToLightConeComponents[FV[p, \[Mu]], n, nb]
21nbμ(n⋅p)+21nμ(nb⋅p)+pμ⊥
ToLightConeComponents[GA[\[Mu]], n, nb]
γˉμ⊥+21nμγˉ⋅nb+21nbμγˉ⋅n
ToLightConeComponents[GS[p], n, nb]
21(n⋅p)γˉ⋅nb+21γˉ⋅n(nb⋅p)+γˉ⋅p⊥