Recommended by us: Violation of the "first" Heisenberg's Uncertainty Principle

“ Synopsis: The Certainty of Uncertainty L. A. Rozema et al. Phys. Rev. Lett. (2012) Violation of Heisenberg’s Measurement-Distrurbance                                           Relationship by Weak Measurements Lee A. Rozema, Ardavan Darabi, Dylan H. Mahler, Alex Hayat,                                   Yasaman Soudagar, and Aephraim M. Steinberg Phys. Rev. Lett. 109, 100404 (2012) Published September 6, 2012 When first taking quantum mechanics courses, students learn about Heisenberg’s uncertainty principle, which is often presented as a statement about the intrinsic uncertainty that a quantum system must possess. Yet Heisenberg originally formulated his principle in terms of the “observer effect”: a relationship between the precision of a measurement and the disturbance it creates, as when a photon measures an electron’s position. Although the former version is rigorously proven, the latter is less general and—as recently shown—mathematically incorrect. In a paper in Physical Review Letters, Lee Rozema and colleagues at the University of Toronto, Canada, experimentally demonstrate that a measurement can in fact violate Heisenberg’s original precision-disturbance relationship. (Continue to read on physics.aps.org)

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The (business) rule of Nature

“ Guest Post: Terry Rudolph on Nature versus Nurture

by Sean Carroll

Everyone always wants to know whether the wave function of quantum mechanics is “a real thing” or whether it’s just a tool we use to calculate the probability of measuring a certain outcome. Here at CV, we even hosted a give-and-take on the issue between instrumentalist Tom Banks and realist David Wallace. In the latter post, I linked to recent preprint on the issue that proved a very interesting theorem, seemingly boosting the “wave functions are real” side of the debate.

That preprint was submitted to Nature, but never made it in (although it did ultimately get published in Nature Physics). The story of why such an important result was shunted away from the journal to which it was first submitted (just like Peter Higgs’s paper where he first mentioned the Higgs boson!) is interesting in its own right. Here is that story, as told by Terry Rudolph, an author of the original paper. Terry is a theoretical physicist at Imperial College London, who “will  work on anything that has the word `quantum’ in front of it.” (continue to read on Cosmic Variance) .                                                                                                                                        ”