  Quantum theory of surface plasmons is very important for studying the
interactions between light and different metal nanostructures in
nanoplasmonics. In this work, using the canonical quantization method, the SPPs
on nanowires and their orbital and spin angular momentum are investigated. The
results show that the SPPs on nanowire carry both orbital and spin momentum
during propagation. Later, the result is applied on the plasmonic nanowire
waveguide to show the agreement of the theory. The study is helpful for the
nano wire based plasmonic interactions and the quantum information based
optical circuit in the future.
