▎ 摘　　要

The valley pseudospin is an inherent electron degree of freedom in graphene. This work establishes a theory for manipulation of valley pseudospins at the quantum level, in bilayer graphene. Two key mechanisms of valley manipulation are proposed and valley-based quantum devices-qubits and field-effect transistors-are implemented based on the mechanisms. This work provides a crucial step in paving the way for the experimental realization (expansion) of valley-based quantum (classical) information processing.