I was under the impression that the "double slit experiment" worked as follows:

Any single photon will go through only ONE slit. However, if you send
MANY photons through, the probability distribution of where they
impact behind the slit screen will have the same shape as the squared
magnitude of the intensity of the wave function you would expect from
diffraction.

See: http://en.wikipedia.org/wiki/Double-slit_experiment#Quantum_version_of_experiment

Sean


On 1/24/07, Russell McMahon <apptech@paradise.net.nz> wrote:
> > Given that I was recently told you can "reconstruct" an image from a
> > single
> > photon camera-- possibly!
> >
> > *How* is a different matter ;-)
>
> It's a simple and logical consequence of quantum  mechanics. At each
> possible decision point the universe divides into multiple versions
> which in turn divide into ... as required, until there are enough
> universes carrying enough information to store the image. Seems a bit
> of an extreme waste of universes just to ge get a holiday snapshot
> though.
>
> The same principle is used by quantum computers to carry out
> calculations that under ordinary conditions would require more
> iterations than could, by many magnitudes, have been carried out
> during the whole life ( where 6500 years < Life < 20 billion years) of
> the universe to date. It still takes just as much resource with a
> quantum computer but you are using the resources of all those
> universes in parallel. Or, it will do when they find out how to
> actually build a quantum computer.
>
> If any of the above sounds like bunkum (hopefully it does :-)) then
>
> - How can a single photon provide such an image?
>
> - How can a quantum computer achieve what its proponents expect to
> achieve?
>
> The latter especially seems particularly bizzarre. But there doesn't
> seem to be any more logical one on offer. And, after all, QM works
> superbly but doesn't make any logical sense at all anyway, so why
> should this aspect of it do so.  ? :-)
>
>
>         Russell
>
>
>
>
>
>
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