Abstract
We propose three core ideas: 1. the wave-particle duality of the qudit quantum space; 2. the classification of all elementary quantum gates by ordered pairs of qudit functionals; 3. a new type of quantum gates called the "quantum wave gates". We first study the quantum functionals whose relation to the quantum states is analogous to that between the momentum and position wavefunctions in fundamental quantum physics: a Fourier transform and an entropic uncertainty principle can be defined between the dual representations. The quantum functionals are not just mathematical constructs but have clear physical meanings and quantum circuit realizations. Connecting the partition interpretation of the qudit functionals to the effects of quantum gates we classify all elementary quantum gates by ordered pairs of qudit functionals. By generalizing the qudit functionals to quantum functionals, the new type of "quantum wave gates" are discovered as quantum versions of the conventional quantum gates.