  Quasicrystals are characterized by atomic arrangements possessing long-range
order without periodicity. Van der Waals (vdW) bilayers provide a unique
opportunity to controllably vary atomic alignment between two layers from a
periodic moir\'e crystal to an aperiodic quasicrystal. Here, we reveal a
remarkable consequence of the unique atomic arrangement in a dodecagonal WSe2
quasicrystal: the K and Q valleys in separate layers are brought arbitrarily
close in momentum space via higher-order Umklapp scatterings. A modest
perpendicular electric field is sufficient to induce strong interlayer K-Q
hybridization, manifested as a new hybrid excitonic doublet. Concurrently, we
observe the disappearance of the trion resonance and attribute it to
quasicrystal potential driven localization. Our findings highlight the
remarkable attribute of incommensurate systems to bring any pair of momenta
into close proximity, thereby introducing a novel aspect to valley engineering.
