Possible explanation for the wave-particle duality ?

[bohm2]

Its beyond me why people get caught up in this semantic dead end. Physical theories are mathematical models. Its relation to reality, whatever reality is, there is no agreement on that by a long shot, is a philosophical issue - not physics.

But mathematical models of what, then?

 

[bhobba]

But mathematical models of what, then?

Of abstractions.

Simply go back to Euclidean geometry.

A point is defined as having no size, a line no width. They don't exist - but no one seriously doubts (with caveats from relativity) the results being true. Its used all the time in engineering, surveying, kinematics, all sorts of things without any trouble or questions that its not dealing with reality or whatever. My father used to like laying cement around the house - he would lay out string with pegs and model the strings as lines and pegs as points to do his calculations. The diagrams he drew were not the string and pegs - he abstracted away the inessentials and represented them by the points and lines of Euclidean geometry. That wasn't the reality - it was a conceptual model - but basically - so what?

Now I can't get into the mind of my dad, but he was a very practical minded electrical engineer - but I suspect he would have given you a rather strange look if you said the diagrams he drew wasn't the reality - of course it isn't - but it simply doesn't matter.

Thanks
Bill

 

[stevendaryl]

This is bog standard QM - nothing to do with fields.

Also Vanhees is talking about the formalism of QM. That, for a long time now, independent of any interpretation, has shown the wave-particle duality is well - wrong.

I don't agree that wave-particle duality is wrong. I guess it depends on whether you take the phrase as a precise theory, or as simply a description of quantum behavior. As the latter, it seems pretty appropriate. In a diffraction experiment, both particle-like behavior and wave-like behavior are involved. The diffraction pattern seems very wave-like, with interference and so forth. But the individual dots appearing on a photographic plate are particle-like.

 

[Maui]

I don't agree that wave-particle duality is wrong. I guess it depends on whether you take the phrase as a precise theory, or as simply a description of quantum behavior. As the latter, it seems pretty appropriate. In a diffraction experiment, both particle-like behavior and wave-like behavior are involved. The diffraction pattern seems very wave-like, with interference and so forth. But the individual dots appearing on a photographic plate are particle-like.

I think he was saying the wave-like behavior does not exist as such but is present in special cases. As in - ghosts do not exist but ghost-like behavior can be observed in some specific cases. Which also begs the layman's question - if it walks like a duck and talks like a duck... (by popular opinion) in qm it seems to not be a duck.

 

[wilmor51]

Perhaps wave function collapse can be identified as an unreal conceptual mathmatical response to what is, in fact, an observational collapse from the observing photons present, or reality, into the observing photons past, or unreality, whilst intuitatively understanding, if that is allowed on this forum, that at each ongoing, immeasureable discrete point in time of the collapse, the observing photons temporal position will adjust to be always in the present, or a state of awareness or conciousness, whilst the observed photon will adapt spatial positional change and create time as it moves into the observing photons past as information which can only be realized in the observing photons present.

 

[DevilsAvocado]

In our 3 dimensional space what really happens is not that the particle goes through two slit at the same time and it interferes with itself, it passes only one slit and doesn't interfere with anything, its just the possible paths that are limited for it, and it simply does not cover those places that are impossible for it to go through.

Okay, so what happens to your "3D probability grid" when we close one slit? And the particle goes thru the one left open? What "signaling system" will change the state of "the grid"? To produce the non-interference single-slit pattern?

 

[DevilsAvocado]

The little youtube movie is astonishingly misleading, although usually Lewin's lectures on YouTube are excellent. Lewin doesn't do a specifically quantum-theoretical experiment here (except in the sense that (nearly) everything "classical" is understood as an approximation to something that can be also described by quantum theory).

Besides Walter Lewin, professor emeritus of MIT, it looks like you are also on collision course with PF Mentor ZapperZ ...

= a very dangerous mission

In quantum theory the single-particle wave function however has a probabilistic meaning and does not describe some kind of smearing of the single particle it is describing.

Okay, so which slit is the single electron going through?

And what's you comment on papers like this:

(my bolding)

Two-photon interference in a standard Mach-Zehnder interferometer

A pair of light quanta with different colors (155.9-nm difference in center wavelength) generated from parametric down-conversion was injected collinearly into one input port of a Mach-Zehnder interferometer. Coincidence interference behavior was studied over a wide range of optical path differences of the interferometer. A measurement of 75% interference visibility with oscillation of the pump frequency for a large optical path difference of the interferometer (43 cm) is the signature of a quantum two-photon entangled state, which reflects both particle and wave nature of the light quanta in one experiment.

DOI: 10.1103/PhysRevA.49.4243

 

[DevilsAvocado]

That's why QM was invented in the 1920's and De-Broglies matter waves abandoned.

Stop! Someone need to hurry to NYC and tear down this faulty plaque!

And reclaim the 1937 Nobel Prize in Physics for the Davisson–Germer experiment, and to be absolute safe we should also reclaim the 1997 & 2001 Nobel Prize in Physics, since these are also closely related to the Bose–Einstein condensate, and the cranky non-existing "matter waves"!


P.S: Contemporary papers in Nature, like this; Coherent control of optical information with matter wave dynamics, should of course also be banned!


() <-- Three Wise Guys that matters!

 

[DevilsAvocado]

I was specifically referring to some specific frequencies needed for the operation of MRI scanners(I myself am alive because of existence of such MRI scanners).

Wow, thank god you're alive! :thumbs:

This is probably the best argument I've seen on PF in a long time, but as you see, it doesn't bite on the "Beholders of the Truth". Yes, you are alive, but still very wrong!

Sometimes I get tired... QM works prefect... mathematically... the seventeen (17!) interpretations seems not to do as well...

I like this picture:

The solid cylinder would be the mathematics of QM, the circle the deterministic complex waviness nature, and the rectangle the measurement of quantized probabilities. And people are fighting on what is, or isn't, if it's real, or not – still in the end, everybody get exactly the same results in experiments... and predictions.

Perhaps it's only one "thing"... who knows...

 

[bhobba]

I don't agree that wave-particle duality is wrong.

I don't want to get into a semantic discussion about it.

My view is simply as per the FAQ of this forum:
https://www.physicsforums.com/showthread.php?t=511178
'Secondly, in quantum mechanics, the description and properties of light has only ONE, single, consistent formulation, not two. This formulation (be it via the ordinary Schrodinger equation, or the more complex Quantum Electrodynamics or QED), describes ALL characteristics of light – both the wave-like behavior and the particle-like behavior. Unlike classical physics, quantum mechanics does not need to switch gears to describe the wave-like and particle-like observations. This is all accomplished by one consistent theory.

So there is no duality – at least not within quantum mechanics. We still use the “duality” description of light when we try to describe light to laymen because wave and particle are behavior most people are familiar with. However, it doesn't mean that in physics, or in the working of physicists, such a duality has any significance.'

This is the sense I mean its wrong, I am pretty sure its the sense Vanhees means its wrong; its a concept that is a hindrance once you learn the full quantum machinery - at best its a concept only useful as a motivation in explaining that machinery - and only in some treatments - it's not even mentioned in Ballentine - and I am pretty sure the above reason is why.

Thanks
Bill

 

[bhobba]

Perhaps wave function collapse can be identified as an unreal conceptual mathmatical response to what is, in fact, an observational collapse from the observing photons present, or reality, into the observing photons past, or unreality, whilst intuitatively understanding, if that is allowed on this forum, that at each ongoing, immeasureable discrete point in time of the collapse, the observing photons temporal position will adjust to be always in the present, or a state of awareness or conciousness, whilst the observed photon will adapt spatial positional change and create time as it moves into the observing photons past as information which can only be realized in the observing photons present.

Can't say I follow what you are saying.

But it needs to be pointed out if wavefunction collapse occurs at all is very interpretation dependent.

In many cases, the system being measured is destroyed in which case collapse is a non issue, and when it isn't destroyed you can look upon the observation as a filtering type measurement which is the same as a state preparation procedure - it was in some other state that you may have not even known and you have prepared it in another state - so it changed during that - nothing really to worry about especially if you associate a state with a preparation procedure - which is the modern view.

Thanks
Bill

 

[bhobba]

Besides Walter Lewin, professor emeritus of MIT, it looks like you are also on collision course with PF Mentor ZapperZ

I suspect not.

After all Zapper wrote the FAQ about the wave particle duality that I quoted.

Rest assured if I didn't think Zapper correct, I would have contacted him about his FAQ entry.

But he isn't, and in fact explains it so well I find myself linking to it.

Thanks
Bill

 

[bhobba]

Stop! Someone need to hurry to NYC and tear down this faulty plaque!

Why - its not inconsistent with anything I said.

De-Broglie came up with his matter wave theory about 1923. But things moved fast and it was abandoned when Matrix Mechanics, Dirac's Q numbers, and Schrodinger's wave mechanics (which is a generalization of the matter wave concept coming out of a question someone asked Schrodinger - if you have waves you need a wave equation - he found one) were discovered about 1925-1926. Of those Dirac's Q numbers were in fact more general than the other two. But things moved fast, exactly as that plaque said, and Dirac used his Q numbers to develop his transformation theory in about 1927, which is basically QM as we know it today. He showed the 3 formulations were really 3 different aspects of this one theory:
http://cerncourier.com/cws/article/cern/28693
'However, this general formulation allowed him to go much further. With it, he was able to develop his transformation theory, which showed explicitly (see P Dirac 1927 in Further reading) how it was possible to relate a range of different formulations of quantum mechanics, all of them equivalent in their physical consequences, such as Schrödinger's wave equation and Heisenberg's matrix mechanics. This was an astonishing achievement, which led to a deeper understanding of quantum mechanics and its use. This transformation theory was the pinnacle of Dirac's development of quantum mechanics since it unified all proposed versions of quantum mechanics, as well as giving rise to a continuum of other possible versions. In later life Dirac considered this transformation theory to be his own as no other quantum mechanician had found any hint of it. Altogether, Dirac's quantum mechanics takes a simple and beautiful form, with a structure showing elegance and economy of concept, and linked directly with the classical theory. It showed us a new aspect of our universe, both profound and perplexing in its new concepts, and certainly unexpected.'

Within a very short number of years De-Broglies matter waves was consigned to the dustbin of history and simply an interesting historical interlude.

Of course it does not mean it wasn't crucial to QM's development - and the confirmation of wave like aspects in experiments not worthy of a Nobel prize - it was - but in 1927 a much more general theory was developed that did away with this wave-particle duality stuff - exactly as Zapper explained in the FAQ's.

Of course Dirac got a Nobel prize for his magnificent accomplishment as well.

Thanks
Bill

 

[DevilsAvocado]

This is the sense I mean its wrong, I am pretty sure its the sense Vanhees means its wrong; its a concept that is a hindrance once you learn the full quantum machinery - at best its a concept only useful as a motivation in explaining that machinery - and only in some treatments - it's not even mentioned in Ballentine - and I am pretty sure the above reason is why.

Well, actually it is, and maybe this explains some "interpretational disagreements"...

(my bolding)

The phenomenon of diffraction scattering is not peculiar to electrons, or even to elementary particles. It occurs also for atoms and molecules, and is a universal phenomenon (see Ch. 5 for further discussion). When first discovered, particle diffraction was a source of great puzzlement. Are “particles” really “waves”? In the early experiments, the diffraction patterns were detected holistically by means of a photographic plate, which could not detect individual particles. As a result, the notion grew that particle and wave properties were mutually incompatible, or complementary, in the sense that different measurement apparatuses would be required to observe them. That idea, however, was only an unfortunate generalization from a technological limitation. Today it is possible to detect the arrival of individual electrons, and to see the diffraction pattern emerge as a statistical pattern made up of many small spots (Tonomura et al., 1989).

As I understand Zz, he removes this incompatibility by clearly stating that; "in quantum mechanics, the description and properties of light has only ONE, single, consistent formulation, not two, [... which ...] describes ALL characteristics of light – both the wave-like behavior and the particle-like behavior".

Whilst Ballentine reduces the whole thing to 'statistics', i.e. there is no wave-like behavior in the single particle, but only in the ensemble.

To me, this is a huge difference, since now we are not talking formalism or foundation, but interpretations, which is a completely different enchilada.

(Do I need to say that Ballentine is a prominent advocate of the ensemble interpretation?)

Maybe he is right!?

Well, here we go...

"There are many difficulties with the idea, but the killer blow was struck when individual quantum entities such as photons were observed behaving in experiments in line with the quantum wave function description. The Ensemble interpretation is now only of historical interest." -- John Gribbin

"[...] the notion that probabilistic theories must be about ensembles implicitly assumes that probability is about ignorance. (The 'hidden variables' are whatever it is that we are ignorant of.) But in a non-deterministic world probability has nothing to do with incomplete knowledge, and ought not to require an ensemble of systems for its interpretation" -- David Mermin​

Question: What would happen if the world only was made of only "Ballentineists"? Would we have the electron microscope and neutron diffraction then? And would that be a better world??


P.S: If one would like to quote Zz in favor of "smearing" and simultaneous wave-like/particle-like behavior, that shouldn't be a problem either:

https://www.physicsforums.com/showthread.php?t=511179]It[/PLAIN] turns out that the picture of electrons moving in circular orbits around the nucleus isn’t correct either(*). The solution here is the implementation of Quantum Mechanics via the Schrödinger Equation and the concept of wavefunction. By applying such formalism, the “electron” occupies a volume of space simultaneously, so that it is “smeared” in a particular geometry around the nucleus.

 

[DevilsAvocado]

I suspect not.

There must be some misunderstanding...

http://physicsandphysicists.blogspot.com/2013/01/misconception-of-heisenberg-uncertainty.html]Misconception[/PLAIN] of the Heisenberg Uncertainty Principle - The Video

Back in 2006, I wrote an entry on the misconception of the Heisenberg Uncertainty Principle. I used light going through a single slit to illustrate what the HUP really is.

Now, I've found a video illustrating JUST THAT!

https://www.youtube.com/watch?v=a8FTr2qMutA

I hope that with the video, what I was trying to explain is even clearer than before.

Zz.

 

[DevilsAvocado]

Why - its not inconsistent with anything I said.

Maybe you are right, I'm sorry in that case, it’s just that it feels maybe a little bit 'awkward' to put empirically verified theories in the "dustbin of history"... and as you see the "abandoned matter waves" are still in use in today...

 

[bhobba]

Question: What would happen if the world only was made of only "Ballentineists"? Would we have the electron microscope and neutron diffraction then? And would that be a better world??

It would make no difference.

It makes exactly the same predictions.

Thanks
Bill

 

[probert84]

So many things have been said here, unfortunately I still have not had time to read them completely, but I think some of you have not completely understood what my original assumption was. I can't really explain it better, I'd rather show something similar to it:


so I supposed that the mater (or rather energy) may look like this swarm, and the 'shape' of it is determined by a field of probability. The different behavior we experience may come from the different properties of the structure of the examined object, I mean that there are areas where the energy is more dense (like the birds or thee quanta) and this makes energy appear as a particle, but how these 'densities' move together and their path is determined by a constraint on a larger scale (swarm) which results in wave phenomena. You can't look at them at the same time and 'merge' your viewpoints, because these are two different pieces of the puzzle and put one over another because then one will overlie the other, but you have to put them next to each other along the line where they fit.

 

[atyy]

So many things have been said here, unfortunately I still have not had time to read them completely, but I think some of you have not completely understood what my original assumption was. I can't really explain it better, I'd rather show something similar to it:





so I supposed that the mater (or rather energy) may look like this swarm, and the 'shape' of it is determined by a field of probability. The different behavior we experience may come from the different properties of the structure of the examined object, I mean that there are areas where the energy is more dense (like the birds or thee quanta) and this makes energy appear as a particle, but how these 'densities' move together and their path is determined by a constraint on a larger scale (swarm) which results in wave phenomena. You can't look at them at the same time and 'merge' your viewpoints, because these are two different pieces of the puzzle and put one over another because then one will overlie the other, but you have to put them next to each other along the line where they fit.

Yes, there is an interpretation of non-relativistic quantum mechanics called de Broglie-Bohm theory in which each individual particle has a definite trajectory, but the trajectory is guided by a nonlocal wave. In addition to the dynamics of the wave, and how the wave guides a particle, an important point for reproducing quantum mechanics is a postulate about the initial density or distribution of particles. However, the analogy to the swarm is only partial, so take a look at de Broglie-Bohm theory itself.

Although not exactly the same as de Broglie-Bohm theory, this video of droplets guided by a wave is similar in many respects, and can give some intuition for de Broglie-Bohm theory (I learned about this from Bohm2 who posted it on another thread here). http://web.mit.edu/newsoffice/2013/when-fluid-dynamics-mimic-quantum-mechanics-0729.html

 

[Zag]

Well, the Schroedinger equation is precisely a Diffusion equation with a imaginary/complex diffusion constant. Having said thay, try not to push the analogy too far because, after all, analogies always fail at some point.

 

[Jilang]

Well, the Schroedinger equation is precisely a Diffusion equation with a imaginary/complex diffusion constant. Having said thay, try not to push the analogy too far because, after all, analogies always fail at some point.

Yes Zag, it's intriguing! It's also a diffusion equation with real time replaced with imaginary time depending on how you look at it!

 

[probert84]

@atyy :

Yeah this is exactly what I thought. Nevertheless I claimed that this is the consequence of HUP. Because when you launch a 'particle' (a pack of energy), you know (more precisely) where it is, so it must be uncertain that which one of the slits it goes through, because you must know its momentum to be able to predict that. And the same applies to the particles past, not only to its the future, when the particle has already hit the detector screen, we know its place, therefore we shouldn't be able to know where it came from, and the consequence of this: it must have passed both slits by some chance.

 

[DevilsAvocado]

It would make no difference.

I don't agree bhobba, and the paper l quoted in #42 is just one example of experiments that most probably would not have been made if everybody, in their bones, believed that the ensemble interpretation is the "final truth".

 

[DevilsAvocado]

[...] but how these 'densities' move together and their path is determined by a constraint on a larger scale (swarm) which results in wave phenomena. You can't look at them at the same time and 'merge' your viewpoints,

I'm afraid the "scale factor" has nothing to do with QM, neither has any clustering of particles. To understand how far your swarms of birds are from QM, consider this:

You could send one electron for, let's say, every decade, and continue this experiment for ten thousand years, and then gather all the data, and you will still get the interference pattern. Or, you could set up the double-slit experiment in a thousand different laboratories around the globe, to fire one single electron, and then gather all the data = same interference pattern.

Or if we had the technology – we could perform "The One Single Electron Double-Slit Experiment" in different galaxies, and then gather all the data in one place = same interference pattern!

This has nothing to do with 'swarms' or 'scale' (except it's extremely hard to do with bigger objects).

Your birds would be completely lost if they where to perform those beautiful patterns, one by one (in different galaxies! ).


P.S: Entanglement has absolutely nothing to do with.

 

[bhobba]

I don't agree bhobba, and the paper l quoted in #42 is just one example of experiments that most probably would not have been made if everybody, in their bones, believed that the ensemble interpretation is the "final truth".

The reason its called an interpretation is because there is no way to tell the difference from any other interpretation.

I think questions like you pose are best taken up with historians of science - its really got nothing to do with the actual science - merely how it actually came about. That's an interesting thing in its own right, but not really germane to the question asked by the OP.

Thanks
Bill

 

[probert84]

@DevilsAvocado

You still don't understand it. You think that I say that the other electrons affect the trajectory but I don't. The electron has nothing to do with the interference, therefore it doesn't matter how much time or space is between each launch of the particles, and this is why you get the same interference pattern each time.
The swarm means all the paths what a single electron can take. The swarm is not the electron itself, its just the part of it. Just like when it appears as a particle. It is not a particle, but a particle is a manifestation, a realization of that energy, and basically when you are detecting it as a particle you are realizing that manifestation by localizing it. I would say if you localize any kind of energy, it should appear similar to a particle. Otherwise how could it be localized ? The reason why it appears to be a 'solid' object is because you narrowed its possibilities down, while when you do the opposite it looks more like a wave. So its appearance is rather the end result of your process of examination than the real (or so thought) properties of the energy.

And I meant 'scale' in this interpretation, by larger scale (like local vs global scale) I mean more possibility, more options, more values for the same variable, and I was not referring to it in a meaning of a difference in the size of objects.

I think that energy has no form or 'shape' by itself, it is not determined, until you determine it by your own choice.

Think on it as kinetic energy vs potential energy, for ex imagine a spring dropped down and hitting the ground and squeezing together, now would you say that the energy that the spring carries consists of two different energies (the moving and squeezed one), or its the same energy with two appearances ?

The same is true for the electron or whatever particle. When you are localizing the particle you are narrowing your viewpoint from the energy distribution that is behind the object to a particle, and in the moment when you detect it with a detector it turns into a particle. Its like when the spring hits the ground and gets into a squeezed state. So both the particle and the wave are a form of the same energy, an image, and not the object itself.

 

[bohm2]

You could send one electron for, let's say, every decade, and continue this experiment for ten thousand years, and then gather all the data, and you will still get the interference pattern. Or, you could set up the double-slit experiment in a thousand different laboratories around the globe, to fire one single electron, and then gather all the data = same interference pattern.

I haven't looked at the paper referenced in this paper but how would one interpret these results:

In one experiment, Kim et al. controlled the exact interval between independent signal photons emitted in pairs [12]. As the time delay between photons was increased, first-order interference gradually vanished.

Interpreting Negative Probabilities in the Context of Double-Slit Interferometry
http://arxiv.org/pdf/physics/0611043v1.pdf

 

[bhobba]

I think that energy has no form or 'shape' by itself, it is not determined, until you determine it by your own choice.

I think you need to understand what energy is:
http://physwiki.ucdavis.edu/Classic..._Mass_and_Energy/Noether's_Theorem_for_Energy

Thanks
Bill

 

[atyy]

@atyy :

Yeah this is exactly what I thought. Nevertheless I claimed that this is the consequence of HUP. Because when you launch a 'particle' (a pack of energy), you know (more precisely) where it is, so it must be uncertain that which one of the slits it goes through, because you must know its momentum to be able to predict that. And the same applies to the particles past, not only to its the future, when the particle has already hit the detector screen, we know its place, therefore we shouldn't be able to know where it came from, and the consequence of this: it must have passed both slits by some chance.

@DevilsAvocado

You still don't understand it. You think that I say that the other electrons affect the trajectory but I don't. The electron has nothing to do with the interference, therefore it doesn't matter how much time or space is between each launch of the particles, and this is why you get the same interference pattern each time.
The swarm means all the paths what a single electron can take. The swarm is not the electron itself, its just the part of it. Just like when it appears as a particle. It is not a particle, but a particle is a manifestation, a realization of that energy, and basically when you are detecting it as a particle you are realizing that manifestation by localizing it. I would say if you localize any kind of energy, it should appear similar to a particle. Otherwise how could it be localized ? The reason why it appears to be a 'solid' object is because you narrowed its possibilities down, while when you do the opposite it looks more like a wave. So its appearance is rather the end result of your process of examination than the real (or so thought) properties of the energy.

And I meant 'scale' in this interpretation, by larger scale (like local vs global scale) I mean more possibility, more options, more values for the same variable, and I was not referring to it in a meaning of a difference in the size of objects.

I think that energy has no form or 'shape' by itself, it is not determined, until you determine it by your own choice.

Think on it as kinetic energy vs potential energy, for ex imagine a spring dropped down and hitting the ground and squeezing together, now would you say that the energy that the spring carries consists of two different energies (the moving and squeezed one), or its the same energy with two appearances ?

The same is true for the electron or whatever particle. When you are localizing the particle you are narrowing your viewpoint from the energy distribution that is behind the object to a particle, and in the moment when you detect it with a detector it turns into a particle. Its like when the spring hits the ground and gets into a squeezed state. So both the particle and the wave are a form of the same energy, an image, and not the object itself.

Actually, the picture you paint here is not so much like that of de Broglie-Bohm theory. It is more like the standard textbook picture. Both de Broglie-Bohm theory and the standard textbook picture give the same predictions for non-relativistic quantum mechanics, so they are essentially different methods of calculating the same predictions of non-relativistic quantum mechanics.

In the standard textbook picture, the electron is a wave or a field. Since a wave or field is in general spread out over all space, it does not have a definite trajectory. However, if it happens to be very localized, then we say that it has a definite position in space. In contrast, in quantum mechanics, to have a definite momentum means having a well defined sinusoidal wavelength. A wave which has a well defined sinusoidal wavelength is by definition spread out over all space, and so does not have a definite position. This is the essence of the uncertainty principle. And yes, it is correct that when you measure the position of an electron, you force it to become a well-localized field, which indeed does not have a well defined sinusoidal wavelength, and therefore does not have a well defined momentum.

So the uncertainty principle basically comes about because
(1) the electron is a wave
(2) position is position
(3) momentum is related to wavelength

 

[probert84]

Well I think I paint the same picture because in the de Broglie-Bohm theory there is a carrying wave which defines the possible trajectories of the particle and I found this similar to the swarm which defines the trajectory of a bird in it. I think on this as sort of a random path dispatching algorithm.

Let the slits be dices. Each throw of the dice represents a chosen direction from 1-6 for a signal we want to send. If we throw two dices(two open slits = two possibilities) at the same time, we have 21 options, and these are:

11 22 33 44 55 66
12 23 34 45 56
13 24 35 46
14 25 36
15 26
16

Say we throw '25' then x % of the signal will go towards direction #2 and 100-x % towards #5. When we throw the same direction with both dices (for ex '11'), we must throw again, because otherwise 100% of the signal would go in the same direction and this means 100% accuracy, which we assume to be impossible (and this is where HUP comes in). Hence 11,22,33,44,55,66 fall out. Let this signal be light and what do you see in these directions ? Black lines, and the overall picture is an interference.

 

[DevilsAvocado]

The reason its called an interpretation is because there is no way to tell the difference from any other interpretation.

It's good that we agree on the "interpretational status", since earlier in this thread there were a lot of talk about "formalism" and "bog standard", which of course the ensemble interpretation is nothing like.

I think questions like you pose are best taken up with historians of science - its really got nothing to do with the actual science - merely how it actually came about. That's an interesting thing in its own right, but not really germane to the question asked by the OP.

That would make the "Shut up and calculate!" physicist David Mermin a "historian", which we both know is not true.

"[...] the notion that probabilistic theories must be about ensembles implicitly assumes that probability is about ignorance. (The 'hidden variables' are whatever it is that we are ignorant of.) But in a non-deterministic world probability has nothing to do with incomplete knowledge, and ought not to require an ensemble of systems for its interpretation" -- David Mermin​

I don't think we will get any further on this issue, except to agree on disagreement – you did/do claim the statistical ensemble interpretation to represent the bog standard of QM, fait accompli.

I, in company with prominent physicists, do not agree. Let's move on.

 

[Jilang]

It seems to me that we have the maths to describe the physical process, but no real idea do that that physical process is. Any questions raised about what might be the physical process are classed as "interpretation". This appears to be regarded as a type of mysticism or witchcraft. So it's off to the ducking stool, the thread is closed, deleted if you are less lucky. Either way we die.

 

[DevilsAvocado]

The same is true for the electron or whatever particle. When you are localizing the particle you are narrowing your viewpoint from the energy distribution that is behind the object to a particle, and in the moment when you detect it with a detector it turns into a particle. Its like when the spring hits the ground and gets into a squeezed state. So both the particle and the wave are a form of the same energy, an image, and not the object itself.

It's good that you try to visualize and make pictures of the problem (it's basically what I do all the time... ), but you have to realize that QM is nothing like our classical "everyday experience", and sometimes (mostly) – pictures don't make it all the way.

How come??

Well, to begin with, you must have some basic understanding about the mathematics, which is the only foundation of QM. It requires an understanding of complex numbers (and partial differential equations). In our everyday life we use real numbers:

Adding the imaginary unit to a real number forms a complex number:

To make it even 'weirder', the wavefunction does not give any information about the QM particle per se, but only provide the probability of finding the QM particle at a given position:

Left: The real part (blue) and imaginary part (red) of the wavefunction.
Right: The probability distribution of finding the particle with this wavefunction at a given position.
The top two rows are examples of stationary states, which correspond to standing waves.
The bottom row an example of a state which is not a stationary state.

As you see, there are 'imaginary processes' in the calculation of the wavefunction, to make it possible to get the probabilities of a 'real output' in the other end. That is weird!

Therefore, to translate your picture of "energy distribution", we must be able to calculate the energy with complex numbers (i.e. $\sqrt{-1}$), which don't make a happy end for the resolution of the "energy distribution", i.e. it don't work.

To give you some comfort, Erwin Schrödinger – the genius who formulated the Schrödinger wave equation – did not know what it represented at first. He tried to interpret his wavefunction as "the density" of the stuff of which the world is made. He tried to think of an electron as represented by a wavepacket. But wavepackets diffuse, and become indefinitely extended, but how ever far the wavefunction extends; the detection of an electron remains 'spotty', i.e. localized. Hence Schrödinger's 'realistic' interpretation of his wavefunction did not survive.

Then Born came and said that the wavefunction does not represent "the density of stuff", but gives the density of probability (modulus squared).

And this is the theory we have today.

 

[DevilsAvocado]

I haven't looked at the paper referenced in this paper but how would one interpret these results:

In one experiment, Kim et al. controlled the exact interval between independent signal photons emitted in pairs [12]. As the time delay between photons was increased, first-order interference gradually vanished.

Woowa!

If this is true... that would mean that bhobba is right after all!? ()

Must check it out...

 

[bhobba]

you did/do claim the statistical ensemble interpretation to represent the bog standard of QM, fait accompli.

I never claimed that, and its obviously not true.

I claim the ensemble interpretation was related to the frequentest interpretation of probability, Copenhagen the Baysian view.

QM formalism simply speaks of probability without interpretation, as do most areas of applied math. To be specific probabilities enters into it via Born Rule which says the expected value of an observation O of a system in state P is Trace(OP). Nothing about ensembles there. That comes when you try and give meaning to expected value. Most applied mathematicians do that via Kolmogorov's axioms and a reasonable mapping without actually worrying about specifics. But some want to go further and say it applies to statistical ensembles, while others say it applies to a level of belief which is Copenhagen. But really it doesn't make much difference.

Thanks
Bill