Re: Quantum Rebel

[Jesse Mazer]

Actually, looking at the diagram and explanation of the experiment posted at 
http://www.kathryncramer.com/wblog/archives/000674.html I think Saibal Mitra 
and the sci.physics.research poster I quoted may have misunderstood what 
happened in this experiment. I may have misunderstood, but it sounded as if 
both were arguing that the finite width of the wires could erase some of the 
which-path information and explain why you'd see interference at the final 
detectors. But the diagram seems to say that *no* interference was found at 
the detectors----the interference Afshar is talking about was just in the 
fact that no photons were scattering against the wires because they were all 
placed in the interference valleys. So the idea seems to be that 
interference is the explanation for why no photons scatter against the 
wires, but the focusing lens behind the wires makes sure that photons from 
the left slit always go to the left detector and the photons from the right 
slit always go to the right detector--this is the "violation of 
complementarity", that the photons behave like a wave in avoiding the wires 
but behave like particles when arriving at the detectors. I'm not sure that 
the notion of "complementarity" has ever been sufficiently well-defined to 
say that this experiment violates it though, and in any case, as long as the 
results of the experiment match the predictions made by the standard theory 
of quantum mechanics, it cannot be taken as a disproof of the Everett 
interpretation, since the basic idea of the Everett interpretation is to 
keep the standard rules for wavefunction evolution but just to drop the 
"collapse" idea (the projection postulate).

Jesse