Quantum harmonic analysis on phase space

Relative to an irreducible representation of the canonical commutation relations, convolutions between quantum mechanical operators and between functions and operators are defined, for which the usual Weyl transform acts as a Fourier transform. Basic properties of these operations are developed in close analogy to harmonic analysis on R2n. Using the quantum version of Wiener’s approximation theorem, a natural one‐to‐one correspondence between the closed, phase‐space translation invariant subspaces of classical and quantum observables is established.