Quantum Fourier transform over a finite abelian group
= Quantum Fourier transform over a finite abelian group
{title2=$\operatorname{QFT}_G$}
For a <finite abelian group> $G$ with character group $\widehat G$, the quantum Fourier transform is
$$
|g\rangle\longmapsto\frac1{\sqrt{|G|}}\sum_{\chi\in\widehat G}\chi(g)|\chi\rangle,
$$
up to complex conjugation according to the transform convention.