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 sigma(omega)=N sigma(uni) in both low and high-frequency limits. [sigma(uni)=(pi/2)e(2)/h]. We use this physics to relate intermediate frequency conductivity trends to qualitative characteristics of the multilayer stacking sequence.