Talk:Afshar experiment/Archive 16

message: The quoted text creates the impression that the text is refering to Afshar's experiement.  In fact it is not, it is refering to Unruh's example experiements which he claims are equivalent, although this is perhaps debateable.  Additionally the only way we could be sure of what Bohr would think about any experiment would be to ask him, and Bohr is currently unavailable for comment. Dndn1011 10:00, 22 November 2006 (UTC)
replies: text: You are both judging content which is OR -- the text reports Unruh's opinion, which is noteworthy and credible because of Unruh's reputation & trackrecord as a physicist.  I think the correct response is to add a rider that Unruh's comments are about a setup he claims is equivalent to Afshar's. --Michael C. Price talk 10:21, 22 November 2006 (UTC)
replies: text: No after reading Unruh's text it became clear that he was not refering to Afsha's experiment.  But the statement itself is expressing Unruh's opinion of what Bohr's opinon might have been on Unruh's experiment.  That's three levels of indirection, and it is this I objected to.  As for the experiements being equivalent, I am not so sure.  I mean I may be wildly wrong but I get the impression the argument goes "We can express both experiments the same way methematically therefore they are equivelent".  This is logical only as long as the assumptions being made are valid and equivalent for both experiments.  The biggest difference I see is simply that Afshar's experiment does not require multiple runs with modifications to the set up to show wave or particle behavior.  Afshar's experiment shows both at the same time, in the same experiment, without the need to modify the apparatus.  Each photon in its course unambiguously demonstrates how a single photon has both passed through both holes and only one hole in the course of its journey, and thus how it has behaved according to both models.  This is not the case in Unruh's example. That such a conlusion should be impossible means that an assumption is being made, such as the assumption that photons actually travel.  To quote Bohr "Nothing exists until it is measured".  If we believe this then there is no conflict, and no explanation. Dndn1011 13:23, 22 November 2006 (UTC)
replies: text: Since Unruh believes his setup equivalent to Afshar's his comments are addressed to both experiments.  You say Afshar's experiment does not require multiple runs, but it does in the sense that many photons must pass through the apparatus.  I don't think you are in a position to give a meaningful critique of Unruh's experiment in comparison to Afshar's when you don't have a deep understanding of the physics.  (I don't mean that in a nasty way, but you are clearly in the process of learning about the basics of quantum mechanics: Unruh has spent his entire career on very advanced quantum physics.) --Michael C. Price talk 06:57, 23 November 2006 (UTC)
replies: text: I make no claim to be knowledgeable in Quantum Mechanics, but I am good at perceiving holes in logical arguments.  I may not have spent my entire career on very advanced quantum physics, but I have spent my entire career on very advanced computer programming.  And so I am very well trained in logical reasoning.  I am qualified to make observations about the comparison of the two experiments without needing to know about the details of quantum mechanics.  I can not do this formally (I am lacking the training to do so).  But I can present a logical argument.  And here it is:  if we find that fewer photons than expected are lost through hitting the wires and more than expected land on either detector, then we conclude that some photons must have avoided the wires due to interference and also been detected.  To clarify by example: if 100 photons are fired and 99 hit the targets, where we would expect only 93 to do so (which can be verified by looking at the loss with one hole closed), then we conclude that 6 photons must have avoided the wires where they would be expected to hit them, while also being detected as having come through a particular hole.  This is just logical.  It is also very different from Unruh's experiement which although fascinating and worthy of an expert in very advanced quantum physics, does not deomnstrate the same thing at all for the reasons I already gave.  Incidentally I agree with you that in a sense Afshar's experiement requires multiple runs, if we take each photon fired as a run through the experiement, but you have conveniently ignored the other crucial thing I said: that Unruh's experiment requires modification of the apparatus between runs whereas Afshar's does not (in the sense that once both holes are open and the wires are in place the behavior that is alledged to invalidate complementarity is demonstrated without needing to adjust the apparatus).  And if I am wrong, I'm the first who'd like to know. But sorry to be satisified I need to see some counter argument better than "you are not qualified to comment".  And I don't mean that in a nasty way either. Dndn1011 09:50, 23 November 2006 (UTC)
replies: text: It is only Fig2 that Unruh presents as equivalent to Afshar's experiment, which is why he refers to "this experiment"; the other set-ups are to illustrate how the concept of complementarity changes with changes of the experimental apparatus, even parts of the apparatus that do not interact with the photons.  And specifically how the insertion of the absorber at 4 (the equivalent of Afshar's wires) changes the interpretation of what complementarity means, from how it would be interpreted within the unwired version of the double slit experiment (or Wheeler's delayed choice experiment, which the unwired Afshar experiment is identical to) -- irrespective of whether the wires/absorber absorbs or scatters any photons. --Michael C. Price talk 12:10, 23 November 2006 (UTC)
replies: text: Thanks for this it has helped me focus better on the problem.  I do see the similarity now (I was getting the wrong end of the stick).  However I still have problems with the asymmetry of Unruh's experiment versus the symmetry of Afhsar's, although it is not clear to me if that makes a difference.  Also I am not sure that the final half silvered mirror is a correct analogy for the lens.  In Unruh's experiment the concept of which way the photon went (so to speak) is hidden behind two half silvered mirrors, whereas in Afshar's the mechanism for detection is a lens which we think of as reliably showing us where light comes from.  In figure 2 we can in truth not know which path (1 or 2) a photon detected at 5 or 6 took because we cannot measure this.  It is an assumption based on the behaviors obvserved in figures 1 and 1a.  However the lens should be quite clear about it.  We should be observing the equivalent of path 1 or 2 directly... unless a lens connot be assumed to demonstrate where photons came from.  This may be what Danko was hinting at with something significant about "lens function".  Anyway, I will look into this more.  Dndn1011 14:07, 23 November 2006 (UTC)
replies: text: Glad it helped.  Reading (and re-reading) Unruh's experiment helped me develop my understanding of complementarity as well: complementarity seems to be a protean shape-shifter that can adapt to conform to any experimental set-up.  Re mirrors vs lenses, IRL we find they are both equally reliable, so I don't see substituting one for the other is a problem, although the experiment would need a bit of redesign to accommodate this. --Michael C. Price talk 14:24, 23 November 2006 (UTC)
replies: text: Re: shapeshifter.  Yes, this much I had gathered and rather like a claim that certain substances cure all ilnesses, I have to admit it does not sit well with me.  If taken too far it becomes "We can explain why we do not need to try to answer that question", applied to every occasion we find a conflict.  It may be true, or it may be it is masking the truth.  As for the half silvered mirrors vs. lenses, lenses behave entirely predictably whereas half silvered mirrors are unpredictable (taken on a photon per photon basis).    This might be a crucial difference. Dndn1011 14:52, 23 November 2006 (UTC)
replies: text: Good point about the half silvered mirrors: I was thinking only about fully silvered ones.  --Michael C. Price talk 17:17, 23 November 2006 (UTC)

text: Danko, English can describe QM as well as maths.  You, like Afshar, are too quick to assume others are idiots, which reduces your credibility to near Afshar's I'm afraid.  Please adhere to your earlier agreement not to edit the article.  I shall look at your paper shortly; no matter what I think of it I strongly urge you to consider why it is that you use as many exclamations marks "!" as Afshar.  And do you really think that impresses people about anything except your emotional balance and lack of objectivity? --Michael C. Price talk 06:57, 23 November 2006 (UTC)
replies: text:  Dear Mike, I am exhausted from derrogative attacks such as yours. Whether I use exclamation marks, or not is my own business. This does NOT change the importance of my work - if it is mathematically correct, nothing can change this fact. However you show your incompetence on very basic things, and even do not try to do GOOGLE search before posting your stupid questions. If you find error in my work please post it, but do not accuse me in something before you do efforts to check and verify that what I have written is really wrong. Thank you for your cooperation in advance. I have decided to reply only e-mail queries, and work on something else. Afshar's discussion is closed topic for me. What I wanted to say, is said in my PhilSci paper, ID 3048. Danko Georgiev MD 12:33, 24 November 2006 (UTC)
thread_title:  Removed reference to text within Unruh's "Quantum Rebel" page. 

message: I have inserted all the web links into the article, because the big reference section with long web links was too ugly. Now all the links are hidden in the text and clickable. I hope the article looks better now, I haven't touched the content of it. Danko Georgiev MD 11:30, 22 November 2006 (UTC)
replies: text: I don't like it and wish to restore the reference section, which is the normal part of an article.  Who, apart from Danko, objects? --Michael C. Price talk 06:39, 23 November 2006 (UTC)

text: I have restored the standard reference format.  --Michael C. Price talk 07:42, 23 November 2006 (UTC)
replies: text: Though an eye-sore, it is more factual and useful. BTW/ thanks for your kind words as usual.-- Prof. Afshar 08:10, 23 November 2006 (UTC)
replies: text: I'm glad to see we can agree on somethings.  --Michael C. Price talk 08:33, 23 November 2006 (UTC)

text:  I don't understand your reasoning. In or to create a nice web page, all links should be hidden. When you give reference, you should provide description e.g. "Lubos Motl's blog" and the link to it be hidden. What is the purpose of web page adress as reference if the reader does not know where he will arive at all. What if this is link to advertisement, or something else. This is encyclopedia, and you's better try to read some of the instructions how to make Wiki-articles. The reference section with web page adresses is ugly, and does not provide any information before clicking on the link. Danko Georgiev MD 08:51, 24 November 2006 (UTC)
replies: text: I'm not sure what you mean by hidden.  Do you mean hidden within the reference, as some of them where originally?  BTW the section is awful now and full of illogical clunky OR and not very informative.  --Michael C. Price talk 10:07, 24 November 2006 (UTC)

text: Cases 2 or 3 looks OK to me.  Case 1 is definitely not OK. --Michael C. Price talk 21:21, 24 November 2006 (UTC)
replies: text:  If so, you can repair the references and notes 6-13, where nude web addresses appear. Better provide some information where these adresses lead to, and hide the web address. The Wikicode for hiding the web adress is shown above in my previous post/example. Danko Georgiev MD 08:17, 25 November 2006 (UTC)
thread_title:  Reference section removed