tag:blogger.com,1999:blog-8666091.post3257374260810932116..comments2019-03-19T19:11:43.501+01:00Comments on The Reference Frame: Nature hypes anti-QM crackpot paper by Pusey et al.Luboš Motlhttp://www.blogger.com/profile/17487263983247488359noreply@blogger.comBlogger10125tag:blogger.com,1999:blog-8666091.post-43282569813015432482012-03-22T17:37:57.256+01:002012-03-22T17:37:57.256+01:00Exactly, the word "compatible" is a vagu...Exactly, the word "compatible" is a vague ill-defined adjective that stores much of their "magic".<br /><br />If you search these comments, someone mentions that it suggests that the word means, in their usage, that the probability of something is nonzero according to a given quantum state.<br /><br />Except that they don't calculate this probability correctly according to the right quantum rules but rather some proto-classical intuitive rules that are never clearly stated. <br /><br />Moreover, they often pretend that things' being "compatible" means, in some sense, that the probability is not only nonzero (which is almost always the case for any proposition) but "close to 100%" so that it implies something.<br /><br />It's just vague emotional rubbish.Luboš Motlhttps://www.blogger.com/profile/17487263983247488359noreply@blogger.comtag:blogger.com,1999:blog-8666091.post-73448176082351347562012-03-22T15:37:52.735+01:002012-03-22T15:37:52.735+01:00what the fuck is 'compatible' ... Lumo, u ...what the fuck is 'compatible' ... Lumo, u r totally correct.... these authors are being too foggy and confusing the readers with the beginning paragraphsbosonhttps://www.blogger.com/profile/07459464266070557300noreply@blogger.comtag:blogger.com,1999:blog-8666091.post-49793907693535430802011-12-07T09:04:05.379+01:002011-12-07T09:04:05.379+01:00Alex, your texts are completely incoherent both wh...Alex, your texts are completely incoherent both when it comes to the terminology and the logic. I can't imagine any interpretation that would make your comment anything else than gibberish.<br /><br />First, you describe some hypothetical crackpot assumptions of their paper and you call it "a statistical interpretation". That's totally wrong because "statistical interpretation" is exactly what you think it's not: it's the assumption that the state vector is purely a tool to calculate probabilities that can be verified statistically, by multiple repetitions of the same situations. See <a href="http://www.nobelprize.org/nobel_prizes/physics/laureates/1954/born-lecture.pdf" rel="nofollow">the 1954 Nobel prize lecture</a> by Born which is called "The Statistical Interpretation of Quantum Mechanics". That's exactly what he got his Nobel prize for, that's exactly how quantum mechanics works, and it can't work otherwise which has been known from the early days of QM.<br /><br />You are clearly ignorant about these basics of QM that have been around for 50-100 years. But you're incoherent when it comes to the presentation of this would-be new hidden-variable pseudoscience as well. You just can't call it an "interpretation of quantum mechanics" because you're clearly trying to construct a totally different, and de facto classical, theory. This language is just like calling creationism "an interpretation of Darwin's theory of evolution". It's just nonsense. It's the very point of quantum mechanics that it's not - it can't be interpreted as - classical physics of any sort.<br /><br />But even if I ignore your totally absurd way how you use the terms "statistical interpretation" and "interpretation" itself, you logic just doesn't add up even with these reversal of the whole terminology. The paper and your logic assumes things that flagrantly contradict the basic postulates of quantum mechanics, so it can't possibly find any contradiction in quantum mechanics or any interpretations of it.<br /><br />You're clearly as deluded a crackpot as the authors of this article itself.Luboš Motlhttps://www.blogger.com/profile/17487263983247488359noreply@blogger.comtag:blogger.com,1999:blog-8666091.post-61509599270674025802011-12-07T02:51:56.659+01:002011-12-07T02:51:56.659+01:00You still don't seem to understand the simple ...You still don't seem to understand the simple logical structure of the paper. <br /><br />They <i>assume, for the sake of argument</i>, a statistical interpretation of QM that postulates that every system has a complete description λ and that wavefunctions encode probability distributions over these λs. These probability distributions are not the standard QM distributions over values of observables that you confuse them with, nor does this "encoding" need to follow any known QM rules. λ is not an entity of standard QM (and certainly not a mixed state as you claim in your terribly convoluted and confused blog post); it is an object of the postulated interpretation, and their goal is to show that such a λ <i>cannot exist</i>. Or rather: if it existed, then a certain experiment would show outcomes at variance with standard QM predictions.Axel Boldthttps://www.blogger.com/profile/06753508755204780662noreply@blogger.comtag:blogger.com,1999:blog-8666091.post-64271817425671911232011-12-06T08:35:35.648+01:002011-12-06T08:35:35.648+01:00Dear Alex, you're exactly as deluded and confu...Dear Alex, you're exactly as deluded and confused about complete basics of quantum physics as the authors of the paper.<br /><br />The fact that the outcomes of experiments can't be deterministically determined has been known since 1925-26 when Max Born's statistical interpretation of QM was fully appreciated and when Heisenberg understood the uncertainty principle.<br /><br />Even when one wants rigorous proofs, the determinism has been excluded since the first moment when people used QM to analyze the double-slit experiment or any other "equally strong" experiment. If there existed at least in principle a way to predict whether the electron would be observed in the left slit or right slit when shined upon, then it would already be guaranteed that it can't contribute to an interference pattern when it's not shined upon. But it does create it, so determinism and a form of realism is automatically eliminated. This has been explained e.g. by Feynman in the 1964 Messenger Lectures but it had surely been known since the 1920s.<br /><br />You're just rotating in circles and you never learn anything new.<br /><br />"When they say "the quantum state is compatible with λ" they mean: the probability distribution encoded by the quantum state assigns a non-zero probability to λ."<br /><br />This is a completely inconsistent sentence. At the beginning, you said that "λ" were some variables including hidden variables, so "λ" is clearly not an object that exists in quantum mechanics. So quantum mechanics can't and doesn't assign probabilities to it. Quantum mechanics only assigns probabilities to observed ("visible") quantities, to the results of measurements.<br /><br />Your comment, much like the paper, is inconsistently using classical and quantum rules to predict phenomena but it doesn't actually have any coherent theory to mix it. The only coherent frameworks in physics we know are classical physics; and quantum physics. No one has ever defined any rules "in between" so one can't discuss this non-existent possibility at all.<br /><br />What actually happens is that you, and all the other deluded people including the authors of this nonsensical paper, are still assuming that the world is classical and they are using classical thinking to try to explain the results of quantum measurements even though this has been known to be impossible for 85 years. Of course that it doesn't make any sense, and they may even see that their reasoning is internally inconsistent. They never learn anything out of their failures so they will never learn the actual rules of quantum mechanics.<br /><br />Cheers<br />LMLuboš Motlhttps://www.blogger.com/profile/17487263983247488359noreply@blogger.comtag:blogger.com,1999:blog-8666091.post-65005257138514558142011-12-06T03:25:44.697+01:002011-12-06T03:25:44.697+01:00Your criticism is misguided, basically because you...Your criticism is misguided, basically because you misunderstand the point of the paper, specifically their usage of λ.<br /><br />Their goal is to refute a particular statistical interpretation of QM, namely the following: (1) every system has a physically complete (but maybe hidden) list of properties λ; (2) the outcome of every measurement on the system is deterministically determined by λ; and (3) the system's quantum state (wavefunction) encodes a mere probability distribution of the λ's.<br /><br />When they say "the quantum state is compatible with λ" they mean: the probability distribution encoded by the quantum state assigns a non-zero probability to λ.<br /><br />They then show that this statistical interpretation leads to consequences that are at variance with classical QM predictions. Further they state that these deviations should be detectable by experiment. They clearly believe that such deviations would not be detected and that the above statistical interpretation is therefore false.<br /><br />The paper is in now way "anti-QM" and your claim that their derivation somehow assumes mutual exclusivity of two non-orthogonal states is besides the point and false.Axel Boldthttps://www.blogger.com/profile/06753508755204780662noreply@blogger.comtag:blogger.com,1999:blog-8666091.post-88330884091311987272011-11-21T19:55:25.064+01:002011-11-21T19:55:25.064+01:00Dear Sandro, what you write is simply not true.
...Dear Sandro, what you write is simply not true. <br /><br />There is no working non-local hidden-variable theory that would agree with the observations (including trivial things such as observations of QFT - multi-particle states with spin, particle creation, and annihilation: each of these things is totally incompatible with the Bohmian pseudoscientific approach) and large classes of non-local hidden-variable models have been falsified as rigorously as local hidden variables, see e.g. <a href="http://motls.blogspot.com/2007/04/falsifying-quantum-realism-again.html" rel="nofollow">Zeilinger et al. 2007</a>. <br /><br />But even before this detailed work whose conclusion was pretty much obvious to everyone who has a clue (which obviously doesn't include you), it's been obvious since 1905 that non-locality flagrantly violates one of the well-established pillars of modern physics, special theory of relativity, so non-local theories can't be the right description of natural phenomena.<br /><br />Both local and non-local hidden-variable theories are dead.Luboš Motlhttps://www.blogger.com/profile/17487263983247488359noreply@blogger.comtag:blogger.com,1999:blog-8666091.post-65494835431127578922011-11-21T16:26:40.521+01:002011-11-21T16:26:40.521+01:00Hidden variable theories are not "anti-QM&quo...Hidden variable theories are not "anti-QM", only <b>local</b> hidden variable theories are. The de Broglie-Bohm interpretation is a trivial counter-example to your assertion which has been known for over 50 years, so you're either ignorant, dishonest and intentionally deceiving people, or simply an idiot.<br /><br />I actually know you're aware of de Broglie-Bohm, because I've posted about it in your comments before, and you replied, so you must be either dishonest or an idiot. Which is it?<br /><br />As for the paper itself, it's simply another nail in the coffin for local hidden variables akin to Bell's theorem. It's not earth-shattering at this point, but neither is it trivial or hogwash as you seem to think.Sandro Magihttps://www.blogger.com/profile/05446177882449578817noreply@blogger.comtag:blogger.com,1999:blog-8666091.post-50294698346693681732011-11-19T16:37:03.406+01:002011-11-19T16:37:03.406+01:00The question being posed is not whether Quantum Th...The question being posed is not whether Quantum Theory is probabilistic or not. Of course Quantum Theory is probabilistic.<br /><br />The question is - is the wavefunction simply a computational device to arrive at probabilities, or is there some reality to it? If it is purely computational, there is no problem with "spooky action at a distance", there is no problem with wave function "collapse" - it is all just ordinary probability theory. However, if the wave function has physical reality, then all these become mysterious.<br /><br />Now, the difference between being a computational device and being physical reality matters only if there is an experimental difference. That is what this paper is trying to find - an experimental difference. Do they succeed in doing so? I don't know.<br /><br />But has anyone on this blog even understood the problem they're trying to address? I don't think so. In particular, Motl gets so fond of his own rhetoric his mind seems to close.<br /><br />Tom Banks wrote: "I am not a historian of science but my cursory reading of the evidence suggests that Einstein understood completely that there were no paradoxes in QM if the wave function was thought of merely as a device for computing probability. He objected to the contention of some in the Copehagen crowd <b>that the wave function was real</b> and satisfied a deterministic equation and tried to show that that interpretation violated the principles of causality. <b>It does</b>, but the statistical treatment is the right one. Einstein was wrong only in insisting that God doesn’t play dice."<br /><br />This paper is an attempt to establish an thought-experimental result that the wave function is real in the sense that Tom Banks wrote above.Arunhttps://www.blogger.com/profile/03451666670728177970noreply@blogger.comtag:blogger.com,1999:blog-8666091.post-82076590129426606712011-11-18T22:09:58.635+01:002011-11-18T22:09:58.635+01:00Indeed, the paper is simply drivel, as it has to b...Indeed, the paper is simply drivel, as it has to be. Hardy already demonstrated in his original 2001 paper, "Quantum Theory from Five Reasonable Axioms", that quantum theory can be derived in entirety from theory of probability. This was further improved by Schack in 2002, who demonstrated that four axioms were sufficient (Hardy's latest revision is dated 2008). What this means is that no amount of intellectual gymnastics rooted in quantum mechanics can disprove its probabilistic interpretation. What more! As far back as 1966 Nelson showed that the Schroedinger equation can be derived from... Brownian motion, sic! (Physical Review, vol. 150, no. 4, pp. 1079-1085) Others demonstrated later that the Feynman formulation can similarly be derived from Brownian motion... so there is probability all over the good old QM. Hardy's work basically generalizes these older results.Gustavhttps://www.blogger.com/profile/04812624716905319048noreply@blogger.com