The wave-particle duality of light has always bugged me. I have recently been thinking about how to simulate diffraction in a raytracer - could a ray perhaps have a certain radius in which it bends towards objects it passes close to?
This does still not account for interference. The fact that a photon travels through both slits of a double-slit experiment can be viewed as a photon in a coherent superposition.
It is quite likely that I am about to embarrass myself in exposing a woeful lack of understanding of optical quantum computing.
Does this then mean that we can use a double slit as an optical quantum computer? Actually, now that I think of it, probably not, because we can't develop gates that change behaviour of certain paths based on whether a photon passed through one slit or the other.
The result of a double-slit experiment (making some idealising assumptions) can be computed through the Fourier transform of a the slit arrangement. This in fact works for any series of slits.
Finally, the clinching proof that this is not possible is that Feynman showed that a classical computer cannot simulate a quantum computer in reasonable time. If it were possible, Feynman would have been wrong somehow.
So rememeber, quantum computing requires a way of interacting your qubits. Interference effects are not enough. I have seen interference being used in several experiments, however.. I don't understand how that works. Photons only interact with themselves... except in non-linear media, I guess. That must be it.
No comments:
Post a Comment