  The performance potential for simulating quantum electron transport on
graphical processing units (GPUs) is studied. Using graphene ribbons of
realistic sizes as an example it is shown that GPUs provide significant
speed-ups in comparison to central processing units as the transverse dimension
of the ribbon grows. The recursive Green's function algorithm is employed and
implementation details on GPUs are discussed. Calculated conductances were
found to accumulate significant numerical error due to single-precision
floating-point arithmetic at energies close to the charge neutrality point of
the graphene.
