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Bending, not breaking, Heisenberg’s Uncertainty Principle produces double-slit measurements

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Or so they say. At CBC News (June 2, 2011), Emily Chung reports, “‘Impossible’ physics feat traces path of light”:

Canadian researchers have traced the average path of single light particles through two slits, probing the limits of a famous physics principle that seemed to suggest doing so wasn’t possible.“We are all just thrilled to be able to see, in some sense, what a photon does as it goes through an interferometer, something all of our textbooks and professors had always told us was impossible,” Aephraim Steinberg, a physicist at the University of Toronto’s Centre for Quantum Information and Quantum Control, said in a statement.

Results were published in Science. It doesn’t exactly break the rule enunciated by Heisenberg’s uncertainty principle of quantum mechanics but

The technique relies on multiple “weak measurements” rather than precise ones that significantly change the particles’ position and trajectory. 

Thoughts?

Comments
above, this experiment just has so many problems on so many levels, i.e. for one, they are using (averaging) many photons instead of looking at precisely one photon, as well it is contradicted by many other lines of evidence, such as Wheeler's delayed choice, and the experiment I listed in 4, as well as what the quantum entanglement experiment tells us. etc.. etc..bornagain77
June 5, 2011
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BA, Here is another critique of the 'weak measurement' method. It's like I suspected. We're dealing with calculations not measurements, which is understandable since we're dealing with such elusive concepts as QM. I think this experiment actually does nothing to chance established QM. It's more of a test if the methodology itself than the theory.above
June 4, 2011
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I don't think it does get around the measurement problem. I think it mostly gets around making inferences at best. Remember, a single photon was never precisely measured during the experiment, these are averages generated via mathematical analysis. The system as I understand it, even in this experiment is still indeterministic. All they seem to have done is simply follow an average "path" of a bundle of so called 'weak' measurements (that still disturb the system but not 'appreciably' (word games?). I don't think this does anything to undermine standard QM interpretations. In fact, the more I think of it, the less substantial it appears to be.above
June 4, 2011
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I don't know exactly how the 'weak measurement' works, but what they've done, I believe, is simply attack the photon with extremely fine 'pieces' of another photon. This attack would not disturb the moving photon enough to completely destroy its momentum. What they seem to have discovered is that there is a kind of 'directionality' associated with the moving photons. The upshot is: (1) Heisenberg's Uncertainty Principle is kind of smeared, or, a little bit more accurately, broken up into tinier parts; and, (2) that photons don't live in the land of 'superpositions' until a measurement is taken. This is both interesting lab work and fascinating science. I think I remarked just last week that the quantum world, underneath it all, is deterministic, but that we can't really get at this 'underneath' world because of the 'measurement problem'. This experiment gets around the 'measurement problem'. Quite interesting.PaV
June 3, 2011
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BA, I read some more and I have come to the conclusion shared by other readers that the position and momentum of the photon are NOT being precisely measured. But rather a gross idea / statistical average of the momentum is obtained as a means to predict the measurement of the position. The actual values for momentum are simple an average for a HUGE number of photons. As such nowhere during the experiment was there a precise measurement for both the position and momentum of a single photon, meaning that a lot of what is being said is just over-hyped empty claims.above
June 3, 2011
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Thanks above, that's a good link you have found. There is definitely something very fishy going on with the 'weak measurement'.,, As well, I'm glad that someone else picked up on the fact that the 'weak measurement' does indeed seem to offer a tangible falsification to MWI, in what good can be gleaned from the experiment, even though the experiment certainly does not come anywhere near overthrowing the work of Aspect, and company.bornagain77
June 3, 2011
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Hey BA, I did some reading on the article and what people are saying. Some are saying it undermines the Copenhagen interpretation, which I highly doubt. Others say that it refutes the MWI. Others say it's nothing new. The most interesting finding I have is a critique of the method used by the researchers known as the 'weak measurement' : http://www.physicsforums.com/blog.php?b=1225 If their method is questionable, then all they got is a hole in the water and lot of huffing and puffing: In regards to the 'weak measurement' method: "It is nothing but a number obtained when some POSITIVE numbers directly obtained by measurements are put into a weird MATHEMATICAL FORMULA supposed to represent a "physical" quantity called "weak value"."above
June 3, 2011
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I too share bornagain's skepticism. I don't think this does much for determinism and their interpretation is questionable.above
June 3, 2011
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Actually this is the key statement here that calls into question their interpretation: “This weak momentum measurement does not appreciably disturb the system' Thus they have, in fact, ever so slightly disturbed the system,, thus this following experiment needs to be conducted to either verify or falsify their interpretation,,,,,, ,,,I believe that the point, that a photon, as a wave, takes ‘every possible path’ through the double slit, was conclusively here shown when information was encoded onto a single photon: Ultra-Dense Optical Storage – on One Photon Excerpt: Researchers at the University of Rochester have made an optics breakthrough that allows them to encode an entire image’s worth of data into a photon, slow the image down for storage, and then retrieve the image intact. http://www.physorg.com/news88439430.html Just a guess,,, but the fidelity of the image that is stored on a single photon should be distorted if they try any type of ‘weak measurement’ which does not appreciably disturb the system’, to determine any trajectory of the ‘particle’; Furthermore, if they are really trying to reestablish determinism into quantum mechanics, they have a far tougher row to hoe than just performing 'weak measurements' on the double slit,,, The Failure Of Local Realism - Materialism - Alain Aspect - video http://www.metacafe.com/w/4744145 The falsification for local realism (materialism) was recently greatly strengthened: Physicists close two loopholes while violating local realism - November 2010 Excerpt: The latest test in quantum mechanics provides even stronger support than before for the view that nature violates local realism and is thus in contradiction with a classical worldview. http://www.physorg.com/news/2010-11-physicists-loopholes-violating-local-realism.html Quantum Measurements: Common Sense Is Not Enough, Physicists Show - July 2009 Excerpt: scientists have now proven comprehensively in an experiment for the first time that the experimentally observed phenomena cannot be described by non-contextual models with hidden variables. http://www.sciencedaily.com/releases/2009/07/090722142824.htm (of note: hidden variables were postulated to remove the need for 'spooky' forces, as Einstein termed them — forces that act instantaneously at great distances, thereby breaking the most cherished rule of relativity theory, that nothing can travel faster than the speed of light.)bornagain77
June 3, 2011
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God doesn't play dice after all...Kyrilluk
June 3, 2011
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This is interesting. I was reading in a different article than the one cited here, that this gives extra credence to David Bohm's interpretation of quantum mechanics. Essentially, we may live in a deterministic universe after all. Besides believing in a deterministic universe, Bohm also rejects Multiverse theory (he believe there is a single universe) and that the universe is constantly recreating itself at a subatomic level. "This weak momentum measurement does not appreciably disturb the system, and interference is still observed. Both measurements had to be repeated on a large ensemble of particles in order to gain enough information for the whole system, but we did not disturb the outcome at all.” explains Steinberg. "Our measured trajectories are consistent, as Wiseman had predicted, with the realistic but unconventional interpretation of quantum mechanics of such influential thinkers as David Bohm and Louis de Broglie," http://physicsworld.com/cws/article/news/46193DesignFan
June 3, 2011
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I believe that the point, that a photon, as a wave, takes 'every possible path' through the double slit, was conclusively here shown when information was encoded onto a single photon: Ultra-Dense Optical Storage - on One Photon Excerpt: Researchers at the University of Rochester have made an optics breakthrough that allows them to encode an entire image's worth of data into a photon, slow the image down for storage, and then retrieve the image intact. http://www.physorg.com/news88439430.html Just a guess, but the fidelity of the image that is stored on a single photon should be distorted if they try any type of 'weak measurement', to determine any trajectory of the 'particle';bornagain77
June 3, 2011
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