Origin of Universal Optical Conductivity and Optical Stacking Sequence Identification in Multilayer Graphene

We show that the origin of the universal optical conductivity in a normal N-layer graphene multilayer is an emergent chiral symmetry which guarantees that σ(ω)=Nσᵤₙᵢ in both low and high-frequency limits. [σᵤₙᵢ=(π/2)e²/h]. We use this physics to relate intermediate frequency conductivity trends to qualitative characteristics of the multilayer stacking sequence.