Tuesday, February 18, 2014

A drop makes waves – just like quantum mechanics?

My prof was fond of saying there are no elementary particles, we should really call them “elementary things” - “Elementardinger”. After all the whole point of quantum theory is that there’s no point - there are no classical particles with a position and a momentum, there is only the wave-function. And there is no particle-wave duality either. This unfortunate phrase suggests that the elementary thing is both a particle and a wave, but it is neither: The elementary thing is something else in its own right.

That quantum mechanics is built on mathematical structures which do not correspond to classical objects we can observe in daily life has bugged people ever since quantum mechanics came, saw, and won over the physics departments. Attempts to reformulate quantum mechanics in terms of classical fields or particles go back to the 1920s, to Madelung and de Broglie, and were later continued by Bohm. This alternative approach to quantum mechanics has never been very popular, primarily because it was unnecessary. Quantum mechanics and quantum field theory as taught in the textbooks proved to work enormously well and there was much to be done. But despite its unpopularity, this line of research never went extinct and carried on until today.

Today we are reaching the limits of what can be done with the theories we have and we are left with unanswered questions. “Shut up and calculate” turned into “Shut up and let me think”. Tired of doing loop expansions, still not knowing how to quantize gravity, the naturalness-issue becoming more pressing by the day, most physicists are convinced we are missing something. Needless to say, no two of them will agree on what that something is. One possible something that has received an increasing amount of attention during the last decade is that we got the foundations of quantum mechanics wrong. And with that the idea that quantum mechanics may be explainable by classical particles and waves is back en vogue.

Enter Yves Couder.

Couder spends his days dropping silicone oil. Due to surface tension and chemical potentials the silicone droplets, if small enough, will not sink into the oil bath of the same substance, but hover above its surface, separated by an air film. Now he starts oscillating the oil up and down and the drops start to bounce. This simple experiment creates a surprisingly complex coupled system of the driven oscillator that is the oil and the bouncing droplets. The droplets create waves every time they hit the surface and the next bounce of the droplets depends on the waves they hit. The waves of the oil are both a result of the bounces as well as a cause of the bounces. The drops and the waves, they belong together.

Does it smell quantum mechanical yet?

The behavior is interesting even if one looks at only one particle. If the particle is given an initial velocity, it will maintain this velocity and drag the wave field with it. The drop will anticipate and make turns at walls or other obstacles because the waves in the oil had previously been reflected. The behavior of the drop is very suggestive of quantum mechanical effects. Faced with a double-slit, the drop will sometimes take one slit, sometimes the other. A classical wave by itself would go through both slits and interfere with itself. A classical particle would go through one of the slits. The bouncing droplet does neither. It is a clever system that converts the horizontal driving force of the oil into vertical motion by the drops bouncing off the rippled surface. It is something else in its own right.

You can watch some of the unintuitive behavior of the coupled drop-oil system in the blow video. The double-slit experiment is at 2:41 mins

Other surprising findings in these experiments have been that the drops exhibit an attractive force on each other, that they can have quantized orbits, they mimic tunneling and Anderson localization. In short, the droplets show behavior that was previously believed to be exclusively quantum mechanical phenomena.

But just exactly why that would be so, nobody really knew. There were many experiments, but no good theory. Until now. In a recent paper, Robert Brady and Ross Anderson from the University of Cambridge delivered the theory:

While the full behavior of the drop-oil system is so far not analytically computable, they were able to derive some general relations that shed much light on the physics of the bouncing droplets. This became possible by noting that in the range the experiments are conducted the speed of the oil waves is to good approximation independent of the frequency of the waves, and the equation governing the waves is linear. This means it obeys an approximate Lorentz-symmetry which enabled them to derive relations between the bounce-period and the velocity of the droplet that fit very well with the observations. They also offer an explanation for the attractive force between the droplets due to the periodic displacement of the cause of the waves and the source of the waves and tackle the question how the droplets are bounced off barriers.

These are not technically very difficult calculations, their value lies in making the theoretical connection between the observation and the theory which now opens the possibility of using this theory to explain quantum phenomena as emergent from an underlying classical reality. I can imagine this line of research to become very fruitful also for the area of emergent gravity. And if you turn it around, understanding these coupled systems might give us a tool to scale up at least some quantum behavior to macroscopic systems.

While I think this is interesting fluid dynamics and pretty videos, I remain skeptic of the idea that this classical system can reproduce all achievements of quantum mechanics. To begin with it gives me to think that the Lorentz-symmetry is only approximate, and I don’t see what this approach might have to say about entanglement, which for me is the hallmark of quantum theory.

Ross Anderson, one of the authors of the above paper, is more optimistic: “I think it's potentially one of the most high-impact things I've ever done,” he says, “If we're right, and reality is fluid-mechanical at the deepest level, this changes everything. It consigns string theory and multiple universes to the dustbin.”


Mitchell said...

"I don’t see what this approach might have to say about entanglement"

Absolutely. This is like Bohmian mechanics before Bohm, i.e. when the "pilot wave" (that guides particles in such a theory) was conceived as always inhabiting 3-dimensional space, rather than 3N-dimensional configuration space.

There was a long discussion with Brady and Anderson, at Scott Aaronson's blog a year ago, prompted by a paper in which they proclaimed that quantum computing would be hard, basically because they were skeptical about entanglement. Then in a subsequent paper they claimed that Bell inequalities could be violated by local mechanisms...

Robert L. Oldershaw said...

Now that is interesting!

New ideas, lots of physical experimentation, heuristic learning from nature, little abstract hand-waving.


johnduffieldblog said...

You aren't very good at sarcasm, Robert.

Yves Couder has been doing this for almost ten years. And whilst it's nice to look at, bouncing droplets aren't a pretty good model of quantum mechanics. The electron is a spinor. We make it out of electromagnetic waves. A cyclone would be a better analogy. But doubtless it will be another ten years of cloth ears before we see a paper on arXiv about that!

Sabine Hossenfelder said...


Regarding Spinors, maybe you should actually look at the paper. Or at least read the abstract before you start complaining about research you evidently don't follow.

Uncle Al said...

Bee - not silicon, silicone. Silicon is the element. Silicone is generic polydimethylsiloxane,
Me_3Si-[O-(SiMe_2)_n]-0SiMe_3 where Me = -CH_3, or MD_nM.

One can stack a Pousse-Café: paraffin oil (0.85 g/cm^3), water (1.0 g/cm^3), Halovac or Krytox oil (1.87 g/cm^3), gallium (5.9 g/cm^3), mercury (13.5 g/cm^3). Get some Kelvin-Helmholtz instability action, too.

When a rigorously derived mature discipline does not extend, it has a defective founding postulate. The only physics loophole consistent with prior observation is sub-part-per-trillion vacuum chirality acting only upon hadrons (quarks). That explains everything! It's a simple experiment in existing bench top apparatus. Somebody should look. After all, quarks are observed to be chiral, doi:10.1038/nature12964

Plato Hagel said...

You are defining something in quantum field theory by "probable outcome" to which "matters are counted" as if in a configuration space? EX. The Higg's field as a probable outcome in energy determination?

Arun said...

If they can demonstrate that this bouncing silicone oil/droplet system can reproduce the quantum mechanical side of Bell's theorem, it might get somewhere.

johnduffieldblog said...

Sabine: I have looked at the paper! See the Bloch sphere at figure 26 on page 17? Note how they say this diagram should not be over-interpreted. Now look at this. That's your spinor. Only it shouldn't have a surface, just as a cyclone doesn't have a surface. See section 11.10 of John Jackson’s Classical Electrodynamics: "one should properly speak of the electromagnetic field Fuv rather than E or B separately”. E is usually drawn with radial lines of force, B with concentric lines of force. To visualise the field Fuv combine the radial and concentric lines. Go on, try it.

Robert L. Oldershaw said...

It would be interesting to see if one could replace the silicone oil with a plasma of charged particles and the oil drops with nonlinear soliton-like objects.

Seems like this would be a lot harder to do experimentally, but it might be a closer analogy to the atomic case.

[PS: I was NOT being sarcastic, you ...]

johnduffieldblog said...

Not being sarcastic? Sorry Robert. You can emulate quite a lot with Falaco solitons. Or smoke rings. A Falaco soliton is like half a smoke ring. A spin ½ spinor is like a full smoke ring but with an additional "steering wheel" rotation. And fatter, like the spindle-sphere torus. With no surface. And made in pair production from light rather than from smoky air. See this and this and this. Mathematicians/TQFT guys like Atiyah know all about this stuff, but for some strange reason a lot of physicists don't.

L. Edgar Otto said...

Uncle Al,

Why when you freeze a mixture of water and KMnSO4 and freeze it the Potassium Permanganate forms a ball in the center?
Yes John, I am being sarcastic, explain that with your inadequate geometry models.
Fluid mechanics can tell us a lot. Like the role of chaos and monopoles as in a recent article.
Robert, this is a great classical oil drop experiment like measuring the charge of an electron. Even if the experiment fudged by bias it can turn out right.
Or we have an example here of something far from the topic or any physics grounding not long for the dust bin. Nice example John, thanks.
Ever blow a smoke ring and see it oscillate in hexagons or sound making a honeycomb of them on the surface of water?

Robert L. Oldershaw said...

And solitons can be like cyclones and tornados.

Maybe electrons are like tiny, nearly naked and rapidly spinning singularities, at least when they are unbound and free. [Assuming vastly stronger gravitation within atomic scale systems].

The value of Couder's research is that it gets us thinking again, instead of just going round and round in the same old circles.

Maybe it will lead to important insights into the physical events taking place in the microcosm.

Theophanes Raptis said...

Try to solve Einstein-Dirac-Maxwell problem along these lines but then, they don't even remember the link between classical Maxwell theory and Euler hyrodynamics these days..

Robert L. Oldershaw said...

I foresee the coming of a neoclassical understanding of all of nature.

Smoke and mirrors will not be required theoretical tools.

Zephir said...

/* There were many experiments, but no good theory */

The hydrodynamic formulation of pilot wave mechanics already exists from both formal, both qualitative perspective (actually in 2006 I wasn't even aware of Couder experiments).

The complete understanding isn't just in derivation of the similar equations for quantum mechanics and water surface, but in the understanding, why they're similar. (analogously, the fact, you can derive inverse square law for gravity and Coulombic force still doesn't mean, you understand the underlying mechanism of both forces. The point in this understanding is, the space-time is density gradient of particle environment (entropic gradient of space-time microstates). The space-time doesn't behaves LIKE particle environment, it IS such an environment.

dirtyshark said...

Considering the number of phenomena they've been able to test so far, is it really *that* hard to come up with an experiment to see if the silicone drops demonstrate entanglement?

tytung said...

There has been a few other articles on this kind of phenomena, for example:

Phillip Helbig said...

"Does it smell quantum mechanically yet?"

That should be "smells quantum meachanical". Yes, "mechanical" is the adjective and "mechanically" is the adverb. However, it is not the verb "smell" which is being modified, but rather "it". So, as it stands, this asks the question whether something uses its sense of smell via quantum mechanics. Similar constructions are "she looks well" (her eyes function properly, perhaps with glasses) and "she looks good" (her appearance is aesthetically pleasing to the observer).

Phillip Helbig said...

At least superficially, this seems similar to something which Max-Planck-Institute Director Klaus Hasselmann has been claiming for years. Yes, Hasselmann is (or was; he might be retired by now) Director of a Max Planck Institute. No, his institute is not concerned with research in fundamental physics, but rather with meteorology. As far as I know, no-one else (at least no-one else with a scientific reputation) thinks that he has found something significant, but those interested might want to take a look and report back here. :-) (Note that cosmology pioneer Alexander Friedmann also worked in meteorology.)

L. Edgar Otto said...

Phil, my ideas for an abstract reference frame (quasicity) first came watching sheet lightening striving thru a fan and trying to make sense advising pilots in predicting fog patterns on a weather map.
About abstract singularity, while in this new report of a long computer proof humans cannot do, an the sum of ones and minus ones with a surplus of two (duality at subset infinity). Machines are slow with rather simple space relation problems humans seem to be able to see instantly once we imagine 3 and 4 space.
I think Ramsey theory has something to do with this, but if it is new or neoclassical I am not sure.

Sabine Hossenfelder said...


Thanks, I fixed that.

Sabine Hossenfelder said...

Arun: Yes, I agree.

Sabine Hossenfelder said...


You're not making any sense to me. I have no clue what it's supposed to mean that the electron is made of electromagnetic waves. You seemed to be saying nobody working on this tries to reproduce spinors. I was telling you they are doing exactly this. I'm not saying I find this very convincing, but I hear there's more work in the pipe so who knows where this will go. Best,


Sabine Hossenfelder said...


You're asking the wrong question. Nobody has shown that the drops demonstrate entanglement. The question is does that mean they can't or does it just mean nobody has figured out how?

Sabine Hossenfelder said...


Thanks, I fixed that.

johnduffieldblog said...

Edgar: they aren’t my geometry models. Guys like Williamson & van der Mark have come up with them. And Qiu-Hong Hu in Gothenburg, and lots of other people. Phillip pointed out Hasselmann and metrons. Even Wheeler had his geons, No I haven’t seen the hexagonal oscillations in smoke rings I'm afraid.
Robert: cross my heart and hope to die, it isn’t gravity that does it. It’s electromagnetism. Check this out.
Theo: these days they don’t even remember the theory of molecular vortices.
Zephir: the Aharonov-Bohm effect. The droplet emulates the “tiny" particle and the surface waves emulate the pilot waves, but IMHO a better analogy is a cyclone. The eye of the storm is tiny, but it isn't the particle, the storm is the particle. Put a cyclone down next to an anticyclone and they move linearly together. Throw one past the other and they swirl around too. That emulates E and B.

johnduffieldblog said...

Sabine: the electron and the positron can be created in gamma-gamma pair production. Each photon is a singleton electromagnetic wave, E=hf applies. The electron and positron were literally made out of electromagnetic waves. And then you can diffract them. They're standing waves, solitons, vortons, Dirac's belt spinors, call them what you will. People have been "working on this to reproduce spinors for years", but they struggle to get papers into high-impact journals. IMHO you should go and see Qiu-Hong Hu, he's in Gothenburg.

Sabine Hossenfelder said...

John, you did notice that you shifted from electron to 'electron and positron' and from 'made of' to 'created', yes?

L. Edgar Otto said...

Basic science with simple experiments, if you asked me this morning seems like more fun than exhausting labor.

On a wave in the ocean a floating object is not pushed forward but describes a circle.

One would not get sea sick on a ship shaped like a torus.

One can suspend a balance of metal in an electronic magnet as if defying gravity by feedback to a photocell by light past it or blocked by it. Will it stop vibrating?

That an oil drop is suspended so far above the sea is this not seen as no zero on the X axis so physicality is in the math of complex space?

Santayana said of our view of a lake as flat that "man's achievement in archetecture was taking the Euclidean plane and standing it on edge. "

Do two dollops of antimatter attract?

Which way do all the steeples point?

Do kids today think about such things?

johnduffieldblog said...

Sabine: re "John, you did notice that you shifted from electron to 'electron and positron' and from 'made of' to 'created', yes?" No. We all know about conservation of angular momentum and that you can't convert one photon into one electron. And we all know about electron diffraction, the wave nature of matter, and Dirac's belt. Just inflate it to the spindle-sphere torus. A 511keV photon stuck in that configuration is what an electron is. The positron has the opposite chirality. Honestly Sabine, talk to Qiu-Hong Hu in Gothenburg, you won't regret it.

L. Edgar Otto said...

John, the underlying foundational physics is not made if such vortices. Nor of a distinct dead zone in the eye of a hurricaine regardless of how we are to understand chirality in such whatever solitons, spinors, scalors, geons, virtual or real monopoles E=B or not. Same species, different claims and names. Not that it is not physics and a deep elaborate useful one. But it is the foundational physics of which these models are a consequence.
If the general inverse law of gravity and its mirrors mean anything to us as three space then what it should have taught us is that quantum mechanics for its own realm as mystery needs not as a term be an oxymoron.

johnduffieldblog said...

Zephir: it points the way. Think TQFT, and note that the dark line in figure 2 is the same as figure 1 in http://arxiv.org/abs/physics/0512265

Don Foster said...

Very nice.

Exciting to find a little tabletop phenomenon with such rich analogue behavior and perhaps deep implications. The paper seems a wonderful example of the application of the basic methodologies of physics.

Hard for me to sort it out, but do you foresee any possibility that something here might alter the “long-chain”, determinative purview of the fundamental description that was posited in your recent post on free will?


t h ray said...

" ... the idea that quantum mechanics may be explainable by classical particles and waves is back en vogue."

Were that Joy Christian's critics got that memo.

"If the particle is given an initial velocity, it will maintain this velocity and drag the wave field with it."

You bet. Just as Christian's framework shows, in accord with EPR-Bohm, the initial condition determines the relation between particle and wave; i.e., initial velocity is independent of wave frequency because random initial conditions result in smooth classical functions.

To borrow from Philip, it smells nice and looks good to me.


Uncle Al said...

"Thanks, I fixed that." Chemistry drips unfortunate nomenclature. H3C-CCl2-CH3 hydrolyzes to H3C-C(OH)2-CH3 that spontaneously dehydrates to H3C-C(=O)-CH3, which is propanone (acetone, a ketone). Use dimethyldichlorosilane to make the silanone, C=O versus Si=O. Alas, Si=O does not exist (bonding pi-orbitals do not sufficiently overlap).

H3C-SiCl2-CH3 hydrolyzes to H3C-Si(OH)2-CH3 that spontaneously dehydrates to the linear polymer, silicone oil, that is not a "silicone" at all. "Methyl-terminated polydimethylsiloxyl" never became popular.

L. Edgar Otto said...

Doesn't this exeperiment taste a little like GR too? Frame dragging of spinning black holes?

From some coordinate that we find ourselves in a place we extend say a time or cause like sequence into higher dimensional view would it matter if we cannot sense accelerations of accelerations?

The possible confusion here is that in a physical space initial or terminal conditions are not necessarily the same mathematical origin of our starting sequence of expanding view.

Add to this that while any two of these coordinates may correspond the simple black or white of them in a given may not correspond to assign a color to adjacent dimensions.

But the information although complexity itself may seem hopelessly mangled it can in principle be sorted out in intelligible one dimensional modeling by parity relations logically between said dimensions.

A point singularity as abstract origin may be at rest or spin or move and not spin instantly at the same state. Likewise if we have a physical coordinate as termination for binary powers up to the dimension in question.

Robert L. Oldershaw said...

It is possible that the unbound free electron (virtually singular) and the fully bound atomic electron (decomposed into countless virtually infinitesimal charged particles whose spatial distribution is that of Psi-squared) have radically different structures.

Would anyone believe such a radical idea? Not yet!

L. Edgar Otto said...

I would certainly argue that so although as a working paradox. I have only questioned such intuitions informally and intuitively. Your formal idea I never felt radical using a sort of
Mathematical induction. In reverse.

Given two such depth complexity structures as different is there something of structures or spaces between them?

Can they be independent of the idea of particle or field in QM or GR physically?

Look as I type this it takes my own breath away and gives me the uncanny questioning of what thought is between certainty and uncertainty but I now see it may be incomprehensible to others or has been due to their accepted intuitions.

Some have said a polymer out of context of a living organism is just s collection of inert matter yet the exact same atoms in a virus may or may not be virulent. Protien conformality seems a non linear NP/P sort of paradoxical problem.

The new Erdos results known readable only as a proof by massive computation is a clue save to those who would assert silicon is more reliable than their imperfect brain matter. But it should be clear that in depth complexity we can rule out models of physics as illusions or simulations where there is no necessary reason to distinguish self simulations of simulations.

Either way the intuitive stance as the case or in error one pattern colors all such problems.

From here we can think of a structure that is a new class of singularity that may also be at the heart of black hole concepts to which the numerology of certain group numbers makes sense as arithmetic. But in the hard count we just discover this way of seeing things involving self dual and similar 24. dimensional 4D singularly structures.

I hope this makes sense, if not please regard it as perhaps an interesting structure poem.

Robert L. Oldershaw said...

I think stellar scale systems show us visually and at relatively high resolution what atomic scale systems look like, how they move, and how they interact.

No one currently believes me, but I think their children will, or perhaps their children's children.

Don Foster said...

"In any physics experiment you only see what you are prepared to see" -- Yves Couder

That is an experimental result to keep in mind.

There is much interesting comment here, but apparently little real amazement at either Couder’s experiments or the Brady/Anderson paper.

Having a tabletop mechanism mimic even a portion of quantum dynamics at a many orders of magnitude greater scale seems to suggest that there may be a deeper organizing principle at work behind both phenomenon.

Are Brady and Anderson flawed enthusiasts or is it simply a matter of being prepared to see the implications of Couder’s work?

L. Edgar Otto said...

Here is a table top experiment. (I enjoyed demonstrations for my 8th grade general science class making A 's yet everyone else D's except my assistant which got B 's 1959)
Slow motion photos showed a water drop on water and smaller ones bouncing back upward. Take a melted drop of crayon and let it fall toward an inclined plane to freeze.

This tastes of GR if we develop it as calculus contravairiant and all that. Only we should not assume the laws of the universe are uniform in the observable usual sense. They certainly are in a more general QMG with what might roughly describe gravity as a potentially uniform continuous color space. In a sense at unification near singularity covariance and contravariance in differential substitutions are on equal footing.
Trivial says the mathematician or elementary (someone linked to that in a cartoon in line recently) but the physicist having understood a problem says bored! This is not to say we cannot still be filled with awe even if curved and lines color what we see of space and time actually or approaching 1's or 0's. I am in awe that this fluid oil experiment can be seen as a finely tuned digital-analog computer.
A social problem for science in the world is this distinction of laws inside or outside a bounded region by which inversion of our local views says as much about open or closed societies or minds.

Neil Bates said...

Fascinating but yeah, no way to get strong long-range correlations and we know that local realism fails and you need FTL connections. And this may help explain particle motion but not varying lifetimes of structureless (?) muons etc. Also, I think the particle/wave duality is not meant to imply both aspects are present "in flight" but rather, the particle aspect is concerned with the localization after an observation. In any case it does come across like Bohmian mechanics, Phil W. will be delighted.

One attempt to get a handle on things (oddly divorced from any kind of *handling* of its hypotheticals!) that I utterly disagree with is MWI. Proponents say that in some extended sense, the wave function continues to evolve according to Schrödinger evolution. The supposed mechanism for separating the superposed potentia is decoherence (as per Zurek et al), and the continuation of all the component states can be looked at as splitting into "many worlds." There is the appeal of (apparent) simplicity and preservation of the quantum rules as such. Analogously to MUH, having all states continue is actually simpler than "something" picking some and not others - and what does the picking? On the other hand, this MWI concept is fraught with problems beyond its current untestability. The argument presenting decoherence as a simulation of collapse is circular and not rigorous. It also may be possible to experimentally recover the superpositions supposedly lost to decoherence [I wrote about this for a FQXI essay: decoherence - an issue of great importance to quantum theories of mind. Proponents struggle to explain the observed Born probabilities for events.

Furthermore, the supposed "continued Schrödinger evolution" really isn't. The multiplication of localized particles at all the possible destinations of the original, is not the same as the original Schrödinger wave that represents a given original amount of mass-energy and momentum (and electric charge as applicable.) Put aside literal collisions between alternatives. Why aren't e.g. electric fields felt superposed from all possible locations of charged objects? The MWI supposedly avoids collapse, but we seem pressed to say "collapse" is whenever something needs to hide and protect the alternatives from each other!

Neil Bates said...

Sorry that URL came out wrong even though it was correct inside the HTML quote marks. It is at www.fqxi.org/community/forum/topic/949.

Sheesh, Captch was "The sucNone."

Neil Bates said...

Another problem with particle+wave style realism, is light. We can imagine electrons being both in some sense, but how credible is a reified nugget photon bouncing around? Most quantum states *don't even have a definite number of photons*, there is uncertainty Δn! I don't see how Bohmians get around that. And furthermore, nugget electrons and especially photons would scatter differently off the fine features of things, that if "really waves", wouldn't they?

Neil Bates said...

Note also the irony that this involves simulating "quantum mechanics" - including things like electrons moving in empty space - by actual substances made of: quantum mechanical particles! So the properties of the real medium can be used to "explain" what the droplets do, but what then is "behind" the quantum mechanics itself? It doesn't have some background ether to do those things, does it? So is this really a semi-classical analogy that can be used to supposedly explain quantum mechanics, or is it, in ironic twist, really quantum mechanics that explains the large-scale behavior instead?

But the proponents might say, it's a model to say the pilot wave concept might be viable. Well that's already been thrashed over so what's the difference? Finally, although a mechanism for simulating probability is given, a genuinely deterministic system will betray it having to do the same thing over if started in *exactly* the same initial state. And even if we can't get it started just the same over again, there would be tell-tale signs of initial state conditions (unlike "real QM", where no matter now perfectly we reproduce the initial state, the outcome is probabilistic.)

L. Edgar Otto said...

GR tells QM how to be determinstic ::
QM tells GR how to be uncertain

If the "real " QM is the final initial ground or foundation as everywhere indeterminant whatever the coherence over a region imagined to be different if a sequence or experiment is set up to be repeated, how would any structure or phenomena arise or exist so too make any other model possible?

Paradox, complimentarity, and contradiction are not necessarily the same working method nor combinations if them together. We should not remove implicit differentiation from the matrices or wave equations of QM as we do of summations in GR if both describes themselves or a greater generality.
This includes whatever we think is happening as a ground at or near singularity to such coordinate systems and equations as to real or declared illusionsal spin speeds or currents we add to to glue intuitive matter bricks together.

General coordinates of origin and order is more complicated than the confusion of a map with the terrain.
It can be imagined as the confusion with any map or terrain and the grid we measure or impose in them.

This can be true of the physics that is mirrored as limits perhaps separately in a grid itself so to distinguish reality of that contained in or summed around regions, the physical terrain.

The standard model is but a supposed absolute zero or nilpotent Dirac algebra over an indefinite theory of everything that inquirey suggests is our greatest physics achievement when it is overly reduced even more than this oil fluid experiment. It begs for generality like curves in gravity - unless if we go back to the white board and started the modeling work again we would find an entirely different standard model given that same initial condition.

When the Hubble eye meets Hubble's red shift of expansion at some place we hold as a singularity but history near origins, speculative models have their place on the still unknown frontiers...the accretion discs around a black hole clumpy, quasifinite like simulation if Nova explosions. Or the new Higgs bubbles where the music of our spheres bids us wake up and smell the Morning Thunder.

Mats Bergenhov said...

If you leave separability and locality behind,
Theory of everything= Monism

Phillip Helbig said...

"Note also the irony that this involves simulating "quantum mechanics" - including things like electrons moving in empty space - by actual substances made of: quantum mechanical particles!"

A similar problem in GR:


Don Foster said...

@ Neil
“…what then is "behind" the quantum mechanics itself?”

I wonder if your question should be real rather than simply rhetorical.

It is not so much whether Couder’s droplets are exact analogues of quantum mechanical entities, but rather whether there may be underlying principles that manifest kindred dynamics at such vastly different scales. Perhaps an analogue here would be soliton formation, which occurs, in diverse material regimes and across scales varying by many orders of magnitude.

Is there something behind quantum mechanics itself? For example, does the probabilistic perspective of QM signal its orientation within a deeper geometry, its alignment along an axis of that geometry. Now, I may lose you entirely here, but consider this rough and ready analogy. In constructing a load bearing structure, a carpenter must determine the “crown” of every board. This property is only ascertained by picking up one end of the board and looking down its length. Does QM’s reliance on probabilities occur within a larger frame?

Whether or not that has any traction for you, there is still the issue that one must be sufficiently mature to accept that QM deals with the “what” and not the “why” of fundamental physics. Is a deeper level of explanation possible? I would like to know why recursive dynamics are universal at every order of magnitude. Is that a question that has been answered or could be?


Plato Hagel said...

Statistical probability always must become a recurring theme, just like the crown(very visual):)

lhcg said...

FYI a team at MIT led by John Bush has been doing the math alongside Couder's experiments for at least three years, and a major recap is coming out next month.
See the work here http://math.mit.edu/~bush/?page_id=484

Don Foster said...

“What ever the case may be in quantum mechanics, the statistics are an incomplete description of our fluid system and emerge from an underlying pilot-wave dynamics.”
(From the video “Pilot-wave dynamics of walking drops,” John Bush, MIT)

So, is this a polite intimation that the statistical description of quantum mechanics may also be incomplete?

Don Foster said...

Whether or not there are multiple worlds, there is some utility to the notion that we each inhabit our own particular Universe, one with its own lights and shadows, its own degree of nearsightedness, its own strategies for getting from here to there, its own unknown quantities and perhaps excesses of the prose.

Here science is the commons with its faith in a one, true, normative universe, something much bigger than us and possibly also true.

In any case it is engaging to watch Couder's droplets scud about upon their little vessels. And it is exciting to consider a precise tabletop mechanism, seemingly fine-tuned to a quantum channel and making pageant of mathematical abstractions.

Perhaps there is hope that some further adjustment would bring into focus the ponderous movements of a graviton, likely much larger, more like a Caribbean cruise ship I suppose. And then there is the possibility of little homunculi aboard -- one can almost see them waving.

If there is something lurking deeper than a quantum description, it is likely to be even more abstract, even less immediately familiar. Yet, on the other hand it would be everywhere manifest, etched in every particular of our immediate vicinity, even in the intersection of a mason’s plumb bob and his spirit level.

While throwing marshmallows at the moon one may speculate upon the nature of some deeper topology. Perhaps it is a case of one with a twist becoming two, two elementals now counterpoised. Further, that all else is emergent between them as they endlessly intertwine, mingling but never quiet meeting because they are inherently cross-purpose in effect, the one energetic, the other information theoretical.

One finds it difficult to hit the moon with a marshmallow; it’s the physics I suppose.

Stuart said...

Coude's model is a true representation of quantum gravity!

Phil Jones said...

The followup paper mentioned by Mitchell in the first comment above is http://arxiv.org/abs/1502.05926. The claim is that you can reproduce the quantum correlations in a CHSH model by purely classical means - in this case orientations with respect to phase vortices. To do this, it appears that you need some long-range order in the medium. This looks like cheating to me, you set things up beforehand to get what you want.