This brings up an interesting question... If a Fourier Transform can be computed from something in which Quantum Bits are implemented by some underlying physical system, then is there anything self-existing in Nature which could be used to (or does in actuality) implement a Fourier Transform? Now, I don't know the answer to that. Something not occuring naturally in Nature is a Prism, and a Prism splits light, and tha…
The lens in the human eye is continuously doing Fourier transforms via the lens:
https://en.wikipedia.org/wiki/Fourier_optics#Fourier_transfo...