  We construct an efficient momentum space approach to the superconductivity in
quasiperiodic multilayer systems. To this end, we extend the Brillouin zone
(BZ) folding method to the superconducting (SC) phases by formulating the gap
equation in the momentum space representation with the BZ folding. In this
picture, we find that the SC order parameters generally exhibit finite momenta,
which corresponds to the spatial fluctuation of the SC order in quasiperiodic
multilayers. We apply the BZ folding method to a one dimensional model of
quasiperiodic superconductors and demonstrate its numerical efficiency compared
to the conventional method based on the real space representation with a large
system size.
