Talk:Afshar experiment/Archive 8

message: I wish to thank Ashibaka, Gareth Hughes, Linas, Drezet, and Carl for their support in keeping Wikipedia objective, informative and fair. Danko Georgiev MD has finally agreed to "restrain [him]self [from] posting comments on the Talk page of Afshar's article." Please kindly report any violations to Gareth Hughes. I would highly appreciate it if somebody would archive this page so we can continue with a “clean slate”, so to speak! Best regards. -- Prof. Afshar 09:27, 7 March 2006 (UTC)
thread_title: '''Thank you!'''

message: Hello, I am new here.
First let me say that I was dismayed to see Professor Afshar being accused of fraud. But I understand it is all settled now.
My view is that
a) this experiment is very beautiful and interesting *because* it shows that QM is true
b) the result was predictable, as whatever the interpretation one prefers, the predictions of QM are independent of the interpretation, and the predictions of QM are clear: what Professor Afshar found is what QM predicts he should have found.
And all interpretations of QM are compatible with his result, just as they are compatible with every other prediction of QM.
For instance: 
a) Everett many-worlds: the photon went through both pinholes, therefore creates an interference pattern, therefore the grid is not seen. Then the photon hits *both* detectors, and the world splits into two new worlds, one where the photon hits one detector and one where it hits the other one. Then whoever, in one of this worlds, watches the arrival in one detector, does not see the other world, but this is a general case of Everett many-worlds, not specific to Afshar's experiement
b) Bohm's mechanics: the photon went through one pinhole, but nonlocally "knows" the other one is open and therefore creates an interference pattern as usual in Bohm's theory. So the grid is not seen. Then the photon ends up wherever Bohm's hidden but nonlocal variable says it should go.
c) Consciouness causes reduction: this reduction is *not* retroactive. The photon went through both pinholes just as in Everett's view. The interference is there, thus the grid is not seen. Then both detectors are hit (with amplitude 1/sqrt(2), square amplitude 1/2), both amplifiers amplify the detection, and if each is connected to a lamp for instance, both lamps lit up (each with square amplitude 1/2). But conciousness does not "accept" this and chooses which one of the two lamps is really lit up. But this happens *after* the photon has gone through the apparatus and does not mean that the photon went through a specific pinhole before going successfully through the grid without seeing it. This is an absolutely general case of "consciouness causes reduction" which is *never* retroactive.
So I claim that this experiment (though I find it fascinating and its importance should not be understated) does not allow to distinguish between various interpretations. Saying that is disproves "wave-particle" duality is not a misunderstanding of the experiment but a misunderstanding of what "duality" really means. Duality is just a word. If one puts "too much" into this word, than this "too much" will be provably false. Duality is true provided one puts into this word just what one should put into it: "in flight" the photon behaves as a nonlocal wave (or, in Bohm's view, a particle that is guided by a wave, the latter nonlocally "knowing" whether the other pinhole is open or not and creates an interference pattern only if the pinhole through which the photon does *not* go through is indeed open). But upon seing its arrival on a detector, one has to interpret it as a particle (either splitting worlds "à la Everett", or consciousness causing reduction "à la Wigner"). The predictions of QM are true, and that is what is important. If the result had been different, then a total re-thinking of QM would have been needed, and I consider as very important that this experiment was done and QM vindicated once more.  Just as it is the case with Professor Aspect's EPR experiments. Please do not understand my comment as belittling the importance of Afshar's experiment as that would be completely contrary to my opinion.
Alfredr 06:51, 30 May 2006 (UTC)
replies: text: I agree with Alfredr -- the results are completely predictable and interpretation independent.  This all sounds very similar to Quantum Optical Tests of Complementarity Bethold-Georg Englert, Marlan O Scully & Herbert Walther, Nature, Vol 351, 111-116 (9 May 1991).  They demonstrated that quantum interference effects are destroyed  by irreversible object-apparatus correlations ("measurement"), not by Heisenberg's uncertainty or Bohr's complementary principle itself.  See also The Duality in Matter and Light Scientific American, (December 1994)
The following discusion does not belong to the Afshar experiment talk page, and has been moved to Alfredr's user page as per the agreed upon statement at the top of the talk page above. You are more than welcome to continue your discussion in your user page, but I will not waste my time responding to Danko Georgiev for reasons discussed before, and well-known to Wiki administrators. Prof. Afshar 19:12, 9 June 2006 (UTC)
thread_title:  Everyone should really agree 

message: Here is Wikipedia link of the appodization effect that was so hotly disputed by Afshar and me. The simulation is performed with Wolfram's Mathematica and it is computer plotted graph not hand-drawn by me. If one needs the notebook source I can send by e-mail. Danko Georgiev MD 02:56, 16 June 2006 (UTC)
thread_title:  Plots of the apodization effect 

message: I looked over the article, and removed the POV tag after some minor edits to the introduction. The article seems very well balanced to me, and is structured in the standard style (introduction, discussion, major criticisms). Sdedeo (tips) 08:05, 18 June 2006 (UTC)
thread_title:  removed POV tag 

message: I added the important work of Greenberger an yasin in the refs given in the theory section.
Drezet 16:35, 19 June 2006 (UTC)
thread_title:  list of refs. for theory section