We consider a single layer graphene nanoribbon with armchair edges in a longitudinally constant external potential and point out that its transport properties can be described by means of an effective non-Hermitian Hamiltonian. We show that this system has some features typical of dissipative systems, namely the presence of exceptional points and of PT-symmetry breaking, although it is not dissipative.
@article{arxiv.1102.2129,
title = {Armchair graphene nanoribbons: PT-symmetry breaking and exceptional points without dissipation},
author = {Maurizio Fagotti and Claudio Bonati and Demetrio Logoteta and Paolo Marconcini and Massimo Macucci},
journal= {arXiv preprint arXiv:1102.2129},
year = {2011}
}