  We investigate the excitation of quantum plasmonic states of light in
graphene using end-fire and prism coupling. In order to model the excitation
process quantum mechanically we quantize the transverse-electric and
transverse-magnetic surface plasmon polariton (SPP) modes in graphene. A
selection of regimes are then studied that enable the excitation of SPPs by
photons and we show that efficient coupling of photons to graphene SPPs is
possible at the quantum level. Futhermore, we study the excitation of quantum
states and their propagation under the effects of loss induced from the
electronic degrees of freedom in the graphene. Here, we investigate whether it
is possible to protect quantum information using quantum error correction
techniques. We find that these techniques provide a robust-to-loss method for
transferring quantum states of light in graphene over large distances.
