A presentation of the quantum Fourier transform from a recursive viewpoint

In this note we construct a quantum Fourier transform circuit in a recursive way, by directly copying the 'divide and conquer' construction of the fast Fourier transform algorithm, rather than using the explicit formula that is given in most introductory texts to quantum computation. We do not pretend this presentation to be original, nor claim for any anteriority. The aim of this paper is purely pedagogical.