Talk:Quantum Fourier transform

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 Field: Discrete mathematics

This page is to me lacking an explanation of how the quantum fourier transform is in practice built up out of a combination of Hadamard and controlled rotation gates, a good explanation can be found at [1] sbandrews 18:37, 18 December 2006 (UTC)

I agree that the page lacks information about the quantum circuit implementation of the QFT. Also, it seems to me that the definition of the QFT given here is backwards to the usual definition of a Fourier transform. That is, the definition here looks like it is actually for the inverse QFT. To see what I mean, compare this article with the Discrete Fourier Transform, or with just the Fourier Transform articles. It makes sense to me that the FT should have a minus sign. The whole point of the FT is to extract a frequency spectrum. However, this is further confused by the fact that the definition given here matches the definition in Nielsen & Chuang's book. Karadoc** 04:08, 2 July 2007 (UTC)

I noticed that too about the minus sign, here and in other QFT papers, perhaps it is just a covention amongst QFT researchers, as it will (i think) still give a fourier transform, just with the coefficients reflected about k=0, if it *is* a convention it would be worth referring to it in the article sbandrews (t) 05:37, 2 July 2007 (UTC)