# Single-particle interference observed for macroscopic objects

1. Sep 28, 2006

### kvantti

http://www.physorg.com/news78650511.html

One millimeter oil droplets interfering with themselves... cool.
It looks like there doesn't seem to be an upper boundary size for quantum mechanical phenomenom.

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2. Sep 28, 2006

### Careful

On the contrary, the experiment shows that interference is very likely a CLASSICAL event (just as happens in Barut self field, the soliton travels through one slit but is influenced by its own wave). The authors moreover mention

In our macroscopic experiment, even though we can observe the whole trajectory, we recover two features of the quantum mechanics experiments," Couder continued. "For one, the individual deviation of a given walker becomes uncertain because of the spatial limits imposed on its wave. Also, interference patterns are recovered in the statistics of successive individual events.''

This fits perfectly the Schrodinger (and de Broglie) picture about the meaning of the quantum wave.

While the scientists observed that each droplet goes through only one slit, the associated wave travels through both slits, with the wave interferences determining the walker’s trajectory. ''

You can already start saying farewell to non locality. This is the best news for local realism in many years : it shows again that radiative phenomena are far from being understood. For those who did not get it : the waves in this experiment are REAL.

Careful

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3. Sep 28, 2006

### kvantti

Daaaamn, I didn't realize that... nice.

What are the local interpretations of QM besides the MWI? The Wikipedia article didn't give much info and I didn't find anything on google.

4. Sep 28, 2006

### Careful

The point is that this experiment strongly suggests that the wavefunction is just a statistical tool. The real single events obey nonlinear equations of motion where the nonlinearity originates from a self coupling to a radiation field (which hence also becomes nonlinear accounting for photon like effects). Therefore, it is meaningless to try to deduce a single event intepretation from the statistical entity, here the *apparant* non locality or consciousness nonsense enters the stage. As I also repeated on several occasions, the description of entanglement is incorrect too. So basically, this experiment severly overthrows the basic postulates of QM; as I said, you turned a bad day into a happy one for me. Again, the waves are real here, unlike in MWI.

Careful

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5. Sep 28, 2006

### kvantti

Could you clarify? I've read that the waveform of a particle is fundamental in the MWI. Do you mean that it isn't?

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6. Sep 28, 2006

### Careful

Sure this is so for MWI. The point here is that this wave is a real LOCAL physical phenomenon due to particle oscillations; moreover this experiment strongly suggests that particles exist all the time, travel definite paths and so on. Moreover one can even follow the path here (which for electrons could also be possible for sufficiently sensitive apparati). So, no consciousness, no giving up of reality, locality ....
Well I have been playing around with the idea for some long time that the wave is due to oscillations of the internal particle degrees of freedom. For an electron, this is the case due to Zitterbewegung (see Barut). So, yes, I believe the wave to be a product of acceleration of matter degrees of freedom. This experiment for sure adds a lot of weight to this hypothesis. So what I say is that MWI is B.S.

Careful

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7. Sep 28, 2006

### kvantti

Those aspects you mention are valid in the MWI. So how do you conclude that the MWI is BS? If anything the experiment shows that the Copenhagen interpretation is BS, atleast from my POV. Don't know then, maybe theres a hole in my knowledge or I just don't get your point. Anyway, I'm off to bed. See you (or read you ) tomorrow. Nighty night.

8. Sep 28, 2006

### Careful

HUH ??? Not at all. In MWI, the particle does not have a definite deterministic trajectory, the wave is NOT a real physical entity : in this experiment the wave is observable *independent* of the extended particle The latter certainly contradicts ANY fashionable interpretation of QM (also BM as a matter of fact).

Careful

9. Sep 28, 2006

Staff Emeritus
So spell it out. Is the wave due to zwitterbewegung or what in your interpretation?

(Added in edit) BTW, does your local realism, with its resemblances to soliton physics, comprise entanglement?.

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10. Sep 28, 2006

### Careful

I answered both of your questions several times even just today. First, yes I believe the apparantly non local one particle phenomena are due to back reaction effects - cfr. Barut self field. Second, entanglement as spelled out in the singlet state is physically incorrect (it does not require a genius to figure that out) and has never been experimentally confirmed : however it might be that the Bell inequalities are *seemingly* violated, I have hinted several times at negative probabilities in that context but I cannot say more about this right now. Another person who has some meaningful things to say about the Pauli exclusion principle is David Hestenes, you might ask CarlB for some references.

Careful

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11. Sep 28, 2006

### RandallB

I’m not so sure I see the big deal here.
They have a droplet of silicone oil on the “surface of a vibrating fluid”
This other fluid remains unidentified so are we suppose to forget this other fluid is there, a real form of aether?
Now the oil interacts with this surface to create a surface wave or “surface wave packet” on the surface of this other fluid.
Sorry I find this not to be a microscopic event, but a tiny example of a macroscopic event – analogous to a small boat going through one of two openings in a sea-wall to find itself affected by its own wave (created in and on that other fluid) coming through that other opening.

Sure it must be exciting to claim they have the largest microscopic event of duality. Exciting too to have local realist giving them great acclaims.
Don’t get me wrong, I’m as hungry for proof of locality as any one, but I’ll not be misled by a red herring; the buckyball is still the largest microscopic item to display true duality.
This drop of oil competes for the title of smallest macroscopic item to duplicate an effect seen with waves of water, adding little or nothing to the puzzle of entanglement.

Sorry to rain on anyones Happy Day parade.

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12. Sep 28, 2006

### Careful

I do not see any reason why the surface of this vibrating fluid is important regarding the selfinteraction effects. The fluidum in this case is just needed to support the drop, that is all.

Sure, but you seem to have forgotten that for example Maxwell's theory has a hydrodynamic interpretation, that black hole models are currently investigated in the context of fluid dynamics and so on. Again, I do not see why the preexisting fluid is important in this context, only the vibration and self induced wave are. This is very clear in Barut Self field for example. But I agree that I do not find the claim in the communication grandiose, what I did find spectacular however was suggestion as if it was a macroscopic quantum event. :rofl:

Entanglement is incorrect, Bell inequality violation could occur.

**
Sorry to rain on anyones Happy Day parade. **

Oh not at all, I was just amused by the fact that some people seem to be surprised by such phenomenon. :rofl:

13. Sep 28, 2006

### Farsight

Careful, are you saying that the Dual Slit experiment has had all the QM guys wasting their time for years with MWI and other postulates because it's all here with a bit of oil and wavy water, dead easy to understand?

14. Sep 29, 2006

### Careful

Well, although the picture is much easier to understand, the mathematics behind it is less trivial since the equation involved is a non linear integro-differential equation. So yes, all the spookyness'' and fuzzy ontology of quantum mechanics (for single particle statistics) comes from treating a non linear problem (in which seemingly non local phenomena can occur) as a linear one. I refer again to A.O. Barut combining relativity and quantum mechanics : schrodinger's interpretation''. By the way, let me tell you that such interpretation had been suggested by Schrodinger in the 1920 ties, but his calculations were rather problematic since he tried this self coupled idea for spin 0 particles (in either complex KG equation). This lead him to an unstable system (the charge distributions just exploded) which seemingly made his program impossible. However, Barut has reinvestigated the same idea but now with Dirac's spinor equation and the resulting system is stable (and gives all QED effects such as Lamb shift, gyromagnetic factor, casimir effect, vacuum polarization ...) due to the internal electron motion (so Zitterbewegung) as far as I understand it. In the above paper he also mentions why the nonlinearity is crucial in explaining the double slit experiment from a local perspective. So please, don't be so surprised, what I am saying is far from radical'' - in that regard it does not seem difficult at all to explain interference in the Buckyball (the very symmetric form of this molecule makes one suspect that the selfinterference pattern is constructive rather than destructive). Now, suppose you learn that all these cherished effects are just classical'' and nonlinear, how would this reflect on considerations towards entanglement'' you think ?? Remember that the latter was a dirty word 35 years ago.

Careful

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15. Sep 29, 2006

### Farsight

Thanks Careful. Food for thought.

16. Sep 29, 2006

### kvantti

If you're referring to my statement, I must apologize. I don't speak english as my native language and I may (and obviously) have made a hasty conclusion. I just got so excited about the topic that I rushed to make a thread about it after reading some of it.

Either way, it sure gives some direction to the nature of quantum interference. I see it as supporting the view of the MWI; others see it differently.

Umm, if the particles are localized and "exist all the time", as in the MWI, doesn't this mean they have definite trajectories aswel? The trajectory of a particle in one universe is influenced by its counterparts in other universes because of interference. So even tho the particle goes thru only one slit in our universe, its trajectory is still affected by its counterparts, aslong as the universes don't decohere.

I see this analogous to the experiment with the oildroplet. Even tho the droplet goes thru only one slit, the wave passes thru both slits and therefore affects the droplets trajectory. Similiarly, a particle goes thru only one slit in our universe, while its counterparts in other universes go thru both slits, enabling the particle to "interfere with itself" and affect the trajectory of the particle (in every universe the experiment is performed).

Heres a couple of papers about locality:
http://lanl.arxiv.org/abs/quant-ph/9906007
http://lanl.arxiv.org/abs/quant-ph/0003146

17. Sep 29, 2006

### Careful

Oh, no problem, I like its topic :rofl:

Then I can only conclude that you did not understand anything about my remarks concerning the *independent* reality of the wave.

Knock, knock the wave is a physical thingie measured independently of the oil drop :uhh: that is what kills of MWI (moreover, everyone in the lab *consciously* agrees that it goes through the same slit :rofl:). Hence, this invalidates all the rest you say...

PS: do not throw papers about locality'' to me, I know very well what locality means and I do not need some crackpot consciousness proponents (that is Deutsch) to lecture me about it.

Careful

18. Sep 29, 2006

### Farsight

Ah. David Deutsche. Not German.

19. Sep 29, 2006

### Careful

No, no Deutsch, it is written like that in the arxiv.

20. Sep 29, 2006

### kvantti

But the wave isn't quantum mechanical. As I said, "I see it analogous..."

The MWI has nothing to do with consciousness. The Copenhagen interpretation deals with the consciousness mumbo jumbo.