Hamiltonian and eigenstate problem is formulated for a bilayer graphene in terms of Clifford's geometric algebra \textit{Cl}3,1. It is shown that such approach allows to perform analytical calculations in a simple way if geometrical algebra rotors are used. The measured quantities are express through spectrum and rotation half-angle of the pseudospin that appears in geometric algebra rotors. Properties of free charge carriers -- pseudospin, velocity and Berry phase -- in a bilayer graphene are investigated in the presence of the external voltage applied between the two layers.
@article{arxiv.1410.2038,
title = {Pseudospin, velocity and Berry phase in a bilayer graphene},
author = {Adolfas Dargys and Arturas Acus},
journal= {arXiv preprint arXiv:1410.2038},
year = {2014}
}