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Fluid Tests Hint at Concrete Quantum Reality
- templeos2 12y agoGod said, "pines finally faster bridle" Pine trees or pine needles?
- adocracy 12y agoLiquid dynamics sounds like an interesting hypothesis, but I agree with the critics that entanglement presents a tough analogy. If Pilot Wave theory suggests that the particle-wave duality is actually two distinct actors - a wave and a particle riding the wave - then 1) each particle has an independently generated wave? and 2) it's difficult to see how that wave could be exactly preserved for both particles over the long distances of entanglement experiments. That's like envisioning a ripple on the far side of a large lake exactly mimicking a ripple here. Granted, the entanglement result of simultaneous collapse of probabilities is also tough to rationally understand. But Pilot Waves maintaining their effect, regardless of various asynchronous interactions encountered between the distances of entanglement experiments, seems naive. Then again, I'm not a particle physicist.
- deleted 12y ago[deleted]
- trhway 12y agoIn interpretation of dual slit experiment people do the main mistake of mixing up the 2 waves - one is wave like quantization of position and another is de Broglie wave-equivalent of the particle. The mix up is caused by photon where both have the same wavelength. They are different in the case of all other particles. Hitachi experiment shows its the best - it clearly shows interference of the positional waves of different particles, not the de Brogile wave (ie. not the particles themselves). It thus also lends very credible support to statistical ensemble interpretation (which, as far as i know, Einstein favored) People frequently bring up single-particle self-interference as explanation for Hitachi too. Well, in case of photon the self-interference pattern looks the same as positional interference because of the same wavelength. In case of electron and especially neutron the self-interference pattern would be much more dense than observed one because of the much higher de Brogile frequency than the frequency of the positional quantization. The wave-like quantization of position is the Pivot Wave. The really important thing here is to understand that Pivot Wave isn't a real wave/object. It is just a description of possible positions of the particle at specific times. Like a trajectory of a bullet isn't a real thing, it is just description of possible positions of the bullet at specific times. It is just in QM the trajectories are wave-like quantized and probabilistically spread - that the non-smooth at small scales structure of our Universe shows its "ugly" face :) Again, taking the quantized wave-like trajectory description of a particle for a real thing, the particle itself, is the main misinterpretation that has been going for years, especially in Copenghagen interpretation.
- gohrt 12y agoWhat is a "Pivot Wave"? Do you mean "Pilot Wave"?
- trhway 12y agothanks, it was a mistype, i guess i see "pivot" much frequently than "pilot"
- phkahler 12y ago>>The really important thing here is to understand that Pilot Wave isn't a real wave/object. It is just a description of possible positions of the particle at specific times. Is it possible that pilot waves are ripples in space-time? We should not make strong assertions especially when a theory is young. You make it sound like nothing more than the a regular QM wave function.
- danbruc 12y agoRipples in space-time are gravitational waves. It could be a real wave but the danger is that one introduces a preferred references frame. Not that it would be the end of physics but it would surely be a big surprise.
- Ono-Sendai 12y agoDo you have any more information or references about this, in particular your claim that there are two different wavelengths in play?
- trhway 12y agoit is actually doesn't matter. The de Brogile wavelength can be excluded from consideration completely - imagine an electron as just a very small metal speck whose position function is wave-like quantized - you'd still get the same interference pattern in the double-slit experiment. [The position function is wave-like quantized because it is QM, and thus all the interactions of the particle with environment - ie. electron with the EM field sending it to the screen in this experiment - happens in "quanta"s. ] Don't get me wrong - i'm not denying de Brogile, i'm just saying that wave-like nature of a particle isn't necessary (and thus isn't proven by ) the double-slit experiment. The single-particle double-slits are never really "single" particle - they always show statistical aggregate of many single particles and thus they are explainable by positional quantization alone (of small specks as described above).
- conexions 12y agoAs an answer to the question on entanglement, the FAQ posted above had this to say: In contrast, Bell’s Theorem can be formulated without even speaking about hidden variable theories: the theorem states that some predictions of QM, well confirmed by several experiments, can not be explained by any local theory. And BM is nonlocal, as well as QM is. In fact BM inspired Bell to investigate non-locality, finally leading himto discover his famous inequalities. Bell was one of the most prominent proponents of BM and wrote many articles explaining it in great detail. Also here's a wikipedia article that talks about Bohmian Mechanics and entanglement. http://en.wikipedia.org/wiki/De_Broglie%E2%80%93Bohm_theory#Quantum_entanglement.2C_Einstein-Podolsky-Rosen_paradox.2C_Bell.27s_theorem.2C_and_nonlocality http://en.wikipedia.org/wiki/De_Broglie%E2%80%93Bohm_theory#...
- GregBuchholz 12y agoI've liked: Clearing up Mysteries - The Original Goal http://bayes.wustl.edu/etj/articles/cmystery.pdf http://bayes.wustl.edu/etj/articles/cmystery.pdf " ...we must keep in mind that Einstein's thinking is always on the ontological level; the purpose of the EPR argument was to show that the QM state vector cannot be a representation of the "real physical situation" of a system. Bohr had never claimed that it was, although his strange way of expressing himself often led others to think that he was claiming this. From his reply to EPR, we find that Bohr's position was like this: "You may decide, of your own free will, which experiment to do. If you do experiment E1 you will get result R1. If you do E2 you will get R2. Since it is fundamentally impossible to do both on the same system, and the present theory correctly predicts the results of either, how can you say that the theory is incomplete? What more can one ask of a theory?" While it is easy to understand and agree with this on the epistemological level, the answer that I and many others would give is that we expect a physical theory to do more than merely predict experimental results in the manner of an empirical equation; we want to come down to Einstein's ontological level and understand what is happening when an atom emits light, when a spin enters a Stern-Gerlach magnet, etc. The Copenhagen theory, having no answer to any question of the form: "What is really happening when - - - ?", forbids us to ask such questions and tries to persuade us that it is philosophically naive to want to know what is happening. But I do want to know, and I do not think this is naive; and so for me QM is not a physical theory at all, only an empty mathematical shell in which a future theory may, perhaps, be built."
- abdullahkhalids 12y agoYou are misrepresenting physicists. There have been many many different attempts to talk about quantum theory on an ontological level. Case in point, the widely debated interpretations: copenhagen, many worlds, bohemian etc. However, one reason that physicists don't spend too much time thinking about what quantum theory really means (besides laziness and bad science) is because we know that quantum theory is not the ultimate theory of reality. Why try to force ontology on a theory that can not even answer all empirical questions without ad hoc additions (standard model of particle physics) or force mating with another theory (general relativity)? We are all waiting for a better theory of physics. Of course rewriting the quantum theory in different forms, like this attempt, might help in getting there.
- Estragon 12y agoAre there any experiments where the pilot wave theory and the Copenhagen interpretation predict different results?
- Florin_Andrei 12y agoIf the pilot wave really drives the behavior of the particle to a very large extent, finding such experiments would be exceedingly difficult.
- jostylr 12y agoIn pilot wave theory, one can deduce the standard quantum formalism. Operators, collapse, and all the rest just pop right out. So no, there is no experiment that can tell the difference. It is possible that pilot wave theory has predictions that the standard formalism is silent on. However, something that is inspired by pilot wave theory can be easily co-opted by standard approaches, e.g., Bell's theorem.
- jostylr 12y agoAs an example, it is very easy to place pilot wave theory on manifolds as these are just differential equations. For the standard theory, it is not at all clear what the main operators ought to be such as momentum. Position, yes, but not other things. Of course, once one has pilot wave theory on it, then whatever needs to be deduced can be and then given to the standard theory.
- tim333 12y agoIt depends a bit how you define things. The Copenhagen interpretation has a collapsing wave function doing so in a way where we can't observe it collapse and the pilot wave theory has pilot waves all over the place that have no effect other than guiding the particle in question then effectively disappearing when not needed. If either the collapses or pilot waves were real things I would kind of expect them to be observable in some way, but in both interpretations they are not observable, which leads me to suspect they are not real things and will go the way of the "luminiferous aether".
- pistle 12y agoExcellent. Hope this gets support and more attention. I'm getting tired of explaining how hand-waving about probabilistic magic of subatomic behavior is successful guessing of reality without explaining it.
- hcarvalhoalves 12y agoI'm impressed by the probability distribution graph in the video. I would never expect the random motion to form a wave!
- gfodor 12y agothat's the point, it's chaotic, not random.
- MichaelAO 12y agoFAQ about Bohmian Mechanics (it's very accessible): http://www.mathematik.uni-muenchen.de/~bohmmech/BohmHome/files/Frequently_Asked_Questions_about_Bohmian_Mechanics.pdf http://www.mathematik.uni-muenchen.de/~bohmmech/BohmHome/fil...
- thedufer 12y agoIts certainly accessible, but I'm not sure how much I trust the authors to understand what they're talking about after point 3. > But very often the conclusion that is drawn from this observation is that our _knowledge_ about the path followed by the electron causes the interference pattern to disappear. Although we couch the idea in terms of "knowledge", the usual meaning of that word is not what anyone thinks is actually the trigger. What exactly is meant by "knowledge" is not well-agreed upon, but no one thinks it is something particular to humans (or sentient beings, I suppose) that causes the wavefunction to collapse. It has more to do with whether the information exists - if the particle interacts with something in such a way that its position suddenly becomes deducible, then it collapses. Like I said, the specifics of this are a known hole in the Copenhagen theory - but this "knowledge" tangent is a clear strawman.
- jostylr 12y agoThat FAQ is generated by the students of a very trustworthy group. Students typically setup strawman when explaining things. Look more to the source. Also, they are trying to argue against a theory which no one wants to fully specify. So they have to come up with something definite. And as soon as they do, the other side says "Strawman!" And then proceeds, as you have just done, to refuse to give a definite theory. As a student of that group as well, I can't say that I am all that pleased by that kind of argument. The bottom line is that collapse is untenable. There is no good place to put it and yet it is needed by the standard theory.
- thedufer 12y agoThere is a range of possibilities of what might cause a wavefunction collapse, and the constructed strawman is nowhere near that. It would be like if we claimed the speed of light was 3.2e8 +/- 5e7 m/s and someone decided our whole theory was bunk because the speed of light is obviously faster than 100 m/s. Well yeah, it is, but there's no contradiction here. "if the particle interacts with something in such a way that its position suddenly becomes deducible, then it collapses" would be a theory in the range of possibilities. It would be much more convincing to argue against something like that.
- mrfusion 12y agoAny ideas on how quantum computing would be explained with this model? If quantum behavior is really classical like I think they're claiming, wouldn't that mean quantum computers wouldn't provide any benefit?
- rrss1122 12y agoI'm not sure how quantum computing would be explained, but if it is classical then yes, quantum computers really wouldn't provide any benefit. This brings to mind headlines recently on how so-called quantum computers could not outperform optimized classical computers on algorithms specifically designed to cater to a quantum computer's strengths. Of course, then you would have to argue whether there actually are any quantum computers in existence today, or the quantum computers that are claimed to exist are actually classical computers exploiting some quantum effects.
- lfuller 12y agoThe D-Wave devices that you are referencing are actually quantum annealing machines, not universal quantum computers. A quantum annealing machine is to a universal quantum computer what a mechanical computer is to a digital processor.
- colanderman 12y agoFirst keep in mind that quantum computers have not been proven to be more powerful than classical computers. Keep also in mind that "quantum computing", like "classical computing", is a mathematical model that exists outside of reality. That said, I think the answer to your question is that the "test particle" in the pilot-wave model is always reaching its destination at the speed of light. If however you model the pilot wave with Newtonian physics and place a literal test particle in it, well, even if the particle is moving very fast, its meandering route will all but guarantee a much slower (likely asymptotically slower) traversal than the pilot-wave test particle. But IANAP and welcome corrections.
- jostylr 12y agoBohmian mechanics is not classical mechanics. The wave is guiding the particles. If quantum computing is based on the standard quantum formalism then it is also present in Bohmian mechanics. That's a proven fact. So quantum computing is rather orthogonal to this.
- bitwize 12y agoInteresting. Maybe this will discourage chuckleheads and ne'er-do-wells from citing "quantum physics" as the justifixation for their particular variety of woo? Probably not, but one can hope!
- ben0x539 12y agoIf you can't bullshit your way through criticism with vague-sounding phrases like “As the particles move along, they feel the wave field generated by them in the past and all other particles in the past”, you're not trying hard enough. :v This magical bracelet is powered by the wave field shaping the contours of the superfluid of space time! Carrying you through life on positive pilot waves!
- jostylr 12y agoThis brings to mind a talk by someone I saw once who talked of telling the Dalai Lama about Bohmian mechanics. The response was one of gratitude for he had always felt like standard QM was a bit nonsensical.
- saraid216 12y agoI hope so, mostly because it makes it harder to claim that the universe is non-deterministic; it was QM that really pushed that from vague spiritualism into accepted science.
- spacehome 12y agoYes! But the best theory is not Copenhagen or Pilot Wave. Eliezer Yudkowski has a brilliant treatise on the Many Worlds interpretation here: http://lesswrong.com/lw/r5/the_quantum_physics_sequence/ http://lesswrong.com/lw/r5/the_quantum_physics_sequence/ that really should be required reading for anyone that wants to talk intelligently on the subject. Edit: seriously, don't even bother reading the article. It (like most science journalism) is garbage. Take the time to work through Eliezer's sequence.
- acqq 12y agoSo please explain in a few sentences what is that that Yudkowski writes, did he make any new contribution to the standard model or made something else or do you agree that the standard model is the most researched and most usable model up to now, and he just made a lot of posts where he just writes a lot of text? I see a lot of links in the article you gave, but I don't understand what we're supposed to discover in Yudkowski's writings after trying to follow most of them. There's a lot of free text, not much physics. The standard model is a lot of smart formulas supported by the decades of expensive elaborate measurements (and vice versa), however his texts look more like writings of some philosophy student who knows a little of the math than like a physicist's material. I'd also really welcome opinions of professional physicists. Edit: Wikipedia entry about him seems to fit my impression: http://en.wikipedia.org/wiki/Eliezer_Yudkowsky http://en.wikipedia.org/wiki/Eliezer_Yudkowsky "Yudkowsky (...) is an American blogger, writer, and advocate for Friendly artificial intelligence (...) Largely self-educated."
- gohrt 12y agoThe Standard Model is a model, not an interpretation. Whether Yudkowsky is right or wrong, anyone's interpretation is going to be text, not physics.
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- Sharlin 12y agoThe Standard Model does not concern itself with the various interpretations of quantum mechanics. It can, as of now, neither verify or falsify any of the interpretations which, consequently, are not scientific theories or even hypotheses, but firmly on the side of philosophy of physics. The interpretations are attempts to answer why Nature works as it does, within the framework of the Standard Model which only appears to answer the question how. Yudkowsky certainly hasn't invented the many worlds interpretation, which was originally formulated by the physicist Hugh Everett in 1957. Even though originally scorned, in the more recent times it has gained popularity among physicists. The series of blog posts by Yudkowsky are (in my opinion, at least) a persuasive argument in its favor against the competing interpretations, and are very much recommended reading for anyone who would like to better understand the issue.
- stefantalpalaru 12y agoI would not be surprised if it turns out that the Copenhagen interpretation is a modern phlogiston theory.
- nardi 12y agoAnother anti-Copenhagen argument by Carver Mead: http://www.cns.caltech.edu/people/faculty/mead/Nature_Of_Light_What_Are_Photons.pdf http://www.cns.caltech.edu/people/faculty/mead/Nature_Of_Lig...
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- dnautics 12y agoI was under the impression that Bohmian mechanics were known to be equivalent if and only if hidden variables were strictly non-local (in the case of the macrophysical observations, the "universe" can for a reasonable higher-order approximation be the limits of the chamber being observed). IIRC, There is also an interesting 'alternative' relativity which has non-local effects and a universal frame of reference formulated by a physicist named Frank Tangherlini (I'll be interviewing him this month). It also has weird properties like anisotropy of the vacuum speed of light!! Might be interesting if Bohmian and Tangherlini mechanics provided a better mathematical rapprochement of quantum mechanics with relativity than Copenhagen/Lorentz/Einstein
- jostylr 12y agoI have been contemplating Julian Barbour's work which has a frame of reference in it. This would make it natural as to what the "now" of Bohmian mechanics would be. That "now" is the mystery at the moment.
- pdonis 12y agoI was under the impression that Bohmian mechanics were known to be equivalent if and only if hidden variables were strictly non-local Correct. The same is true of Bell's theorem; it shows that no local hidden variable theory can reproduce the predictions of standard quantum mechanics. It's true that the "local" part often gets left out in pop science treatments of Bell's theorem; but Bell himself was quite clear about it, and about the fact that Bohm's pilot wave theory is nonlocal. The article completely fails to mention this, which IMO is a huge omission.
- svedlin 12y agoAn interesting response to the fluid experiments discussed in the article: http://arxiv.org/abs/1405.0466 http://arxiv.org/abs/1405.0466 Comment on Y. Couder and E. Fort: "Single-Particle Diffraction and Interference at a Macroscopic Scale", Phys. Rev. Lett. (2006)
- dang 12y agoWe changed the url from http://www.wired.com/2014/06/the-new-quantum-reality http://www.wired.com/2014/06/the-new-quantum-reality to be the original source.
- ars 12y agoThanks, because that is a really well written article so I added that magazine to my RSS.
- vitamen 12y agoThis sums up my thoughts exactly. The pilot-wave theory "...seems to me so natural and simple, to resolve the wave-particle dilemma in such a clear and ordinary way, that it is a great mystery to me that it was so generally ignored." I don't run in experimental-physicist circles, granted, but I've definitely encountered countless cases of a clear, obvious, correct solution being brought up and summarily ignored for what proves to be a poor solution. The probabilistic theories have always made for good Science Fiction, but that should hardly matter.
- mpweiher 12y agoThis seems to be common problem. Watzlawick describes an experiment where two people (A and B) are given the task to classify tissue samples as "healthy" or "sick". There is an initial training session where a light tells them whether their answer was correct, with one little caveat: only A gets real feedback. B's light just duplicates A's, so the answers that B receives are essentially random (I think they get different picture as well). Since the task is not very difficult (on purpose), the As learn the task in 80% of the cases. The Bs have a much more difficult task, they are required to try and find order in a random world. They form very complex theories to account for this. However, that's not the experiment quite yet. The real experiment is that As and Bs are then put together to discuss their results. What happens then is stunning: instead of rejecting the B's theories as unnecessarily complex, the As are usually so impressed with the subtle complexity and detailed brilliance of the B's theories, that they change their mind and accept the B theories! When asked who will improve in the next round, all the Bs and most of the As pick the Bs. And they are right, because the As will have accepted at least some of the Bs ideas and thus perform more poorly. Reference: http://omg.pytalhost.net/dls/ebk_wwidw.pdf http://omg.pytalhost.net/dls/ebk_wwidw.pdf (German)
- jamestomasino 12y agoBy far the most fantastic and unbelievable part of this article is the calm thoughtfulness and collaborative criticism in its comments. Thank you, OP, for sharing such a rare gem.
- sriku 12y agoIf you try to create a classical situation that obeys similar mathematics to a quantum situation, you're bound to get "quantum-like behaviour" isn't it? Wouldn't this be some kind of an analog computer for simulating the two-slit experiment in the classical realm? If so, what would this offer to the interpretation of quantum mechanics that cannot be gleaned from the mathematics itself?
- msane 12y agoThe significance is that this is a model of a special, alternate formulation of quantum mechanics called Pilot-wave Theory.
- sriku 12y agopwt is an interpretation. All interpretations of QM share the same mathematics .. or effectively the same maths. Different "interpretations" cannot produce different predictions in experiments. So using an experiment designed to emulate pwt (which afaik violates special relativity) can only say one thing possibly - that if we find it convenient to think in this way in some limited cases of quantum mechanics, we may do so. In other words, it may at best serve as a heuristic to teach children, that they can later grow out of.
- DavidPlumpton 12y agoI was unable to figure out one key thing about this article. Are they claiming that if the droplet is observed while going through one of the slits that the interference pattern will vanish? If not can we really claim a strong analogy with QM?
- ars 12y agoYes. "And just as measuring the trajectories of particles seems to “collapse” their simultaneous realities, disturbing the pilot wave in the bouncing-droplet experiment destroys the interference pattern."