@Don

I'm glad we have a common interest in making QM understandable. QM deals about elementary physical systems. So there are no simpler systems than quantum systems. Unhappily, this simplicity is often veiled by our classical physics spectacles. By the way, I quoted from your essay on my twitter page. I anticipated you were OK about that.

@Ian

1. Thanks for recommending Moore's Quantum volume "Six ideas that shaped physics". If I manage to get a copy under my eyes, I will jump right away to Schrödinger's equation.

2. I'm aware that I don't wipe away all the difficulties in teaching QM, but I believe that with my approach quantum physics may be taught at the same level as classical physics. Classical physics with billiard balls or bullets, quantum physics with rotating arrows. Feynman initiated this approach with his "All we do is draw little arrows on a piece of paper". It is of interest to extend this approach to "All we do is imagining little arrows in 3D space", because QM is fundamentally about objects that are described by vectors, i.e. arrows.

3. Indeed, there have always been attempts to describe reality in terms of waves (periodical behaviour) and particles. Huygens, but also Newton with his corpuscles that are pulsed by his vibrating aether. 17th century physicists already had the feeling for pilot-waves. Funny that, for more than three centuries, we didn't try to put this idea to the test with ordinary systems.

@Frank

In quantum field theories, forces are mediated by particles. The same for ordinary analogues of quantum field theories. I've not worked out any of these analogues to full extent, so I have only some guiding principles, like: the influence of an object decreases as the inverse of the square distance, two needles are weakly coupled if they glide on each other but are strongly coupled when three of them are aggregated, etc.

@Andreas

I totally agree with you that alternative theories have to be measured against the success of QFT. As you may have noticed in my essay, I don't propose an alternative theory. I try to explain QM (and consequently QFT) "as it stands". I don't think we need another theory. There is need for making sense of the theory "as it stands" (Smolin's Problem n°2 in "The Trouble with Physics").

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Arjen, of course I agree that you do not present a new theory but perhaps a new opinion. If I understand it correctly, your opinion would mean that, if we only pursue further in the future, in maybe five years from now we would have a classical mechanics equivalent of pair creation, and--if we try really hard--in ten years we may discover an "ordinary system" made perhaps of balls, sticks, or needles fully equivalent to non-commutative quantum gauge theory.

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Dear Arjen you promised:

@Eckard. I read your essay and will leave a comment on your forum page.

Do not hurry. For your convenience .

Yours sincerely,

Eckard

Andreas,

What you say is indeed close to my opinion, with the following 'important' reserve that there will be only analogues, never 'equivalents', because an ordinary object will never be equivalent to microscopic objects.

I am reticent also in using the qualifier 'classical mechanics' analogues. I prefer to say 'ordinary physics' analogues. Classical mechanics is not well suited to give approaching representations of quantum mechanics. In classical mechanics, one often pictures particles as points. Classical particles than interact with each other through 'mysterious' or 'weird' forces at distance (I say that intentionally to enforce my argument). I would call that classical mumbo jumbo. Quantum particles have a simpler way to interact . An electron goes from place A to B, couples at B with a photon, than travels from B to C, etc. Quantum interactions are better suited to be explained with the help of ordinary contact interactions.

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Dear Arjen Dijksman,

Do not confuse forces at distance with indeed spooky action at distance.

Eckard

Dear Eckard,

Well, I used the words 'mysterious' and 'weird' for classical forces on purpose. One should not forget the 18th century controversy about the cause of gravity, which forced Newton to write in the General Scholium of his Principia: 'I frame no hypotheses'. An 'intuitive' explanation for the cause of classical forces at distance has come with Quantum Field Theories, where forces are mediated by quantum particles. In a certain way, quantum physics has thus removed weirdness from ordinary physics.

For a discussion about the 'weird' entanglement effect brought by quantum physics, a.k.a. 'spooky action at a distance', please consider the above discussion with Matt Leifer.

Regards,

Arjen

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Arjen,

In your last reply to me you said: "As you said it and as I wrote it in the paragraph following my equation (7), Born's probability rule is necessary to reproduce quantum behavior. The evolution equations are not enough. For ordinary rotating needles, Born's rule follows from phase matching of the interacting needles with the pilot-wave."

And the corresponding essay text is the following:

"The projection of a needle on a given axis will evolve sinusoidally. This will affect scattering probabilities. Two needles will therefore collide with a probability proportional to the projection of the first needle times the projection of the second needle on the axis perpendicular to the line joining the centres of both needles."

This is factually incorrect. Suppose needle 1 rotates in a plane perpendicular on the axis between the two needles and suppose needle 2 rotates in a plane including the axis. Then the needles will collide with probability 1 if the distance between the center of the needles is smaller than the needle half length, and not zero as you state. The whole analysis of the probability of needle collision is much more complex than your statement seems to imply.

Obtaining Born's rule is critical of providing a genuine classical mechanics and this can be mathematically shown to be impossible. Here at FQXi, Enrico Prati shows that classical and quantum mechanics cannot be combined based on the GNS construction. Indirectly this means that quantum mechanics cannot be modeled from classical mechanics. Therefore any "modeling" of QM from classical mechanics is misleading.

Florin,

I thank you for your remark which has the advantage of considering the experimental facts and noticing an imprecision in my formulation. My statement "The projection of a needle on a given (fixed) axis will evolve sinusoidally" is correct but afterwards I switch to an undefined (and variable) axis perpendicular to another axis. I should have mentioned that we must consider averages. I beg your pardon for that imprecision. As you wrote, "the whole analysis of the probability of needle collision is much more complex than (my) statement seems to imply". I have not yet found a general statement in terms of scattering cross sections and projection axes. I've worked out some simple analogues where you may retrieve Born's probability rule (see for example my video Quantum probabilities with ordinary objects).

I don't see how the scattering probability of your counterexample gives "1", except for the special cases where the 2 needles' relative translational velocity is extremely slow with respect to their rotational velocity or where the line joining the needles' centres is collinear with both translational velocities.

I completely agree that quantum mechanics cannot be modeled using classical mechanics. In classical mechanics, there is a one to one mapping between the state of the object and the detection result (i.e. location). As you may have verified with your needles counterexample, this classical one-to-one mapping doesn't pertain to spatially extended objects analogies using contact interactions. For one state of the needle, there is a whole set of statistically distributed possible measurement results spreading over the spinning volume of the needle. Commutative algebra doesn't apply to such analogies.

Dear Arjen,

Your quote '.. impossible, to explain in any classical way (..) quantum mechanics' is exactly to the point. Quantummechanics indeed is impossible for classical physics to explain as it is a causal, religious kind of physics, the kind which creates artificial problems which never can be solved as they are brewed out of unfounded assumptions and an outdated notion of reality. As long as we cling to the idea of a particle as some tiny pellet acting as the source, the cause of its wavelike behaviour, we will never comprehend quantummechanics. If particles create and preserve each other by alternately borrowing and lending each other the energy to exist and by this continuous exchange at the same time express their properties, then they are as much the product as the source of their interactions, so there is no need for a pebble at the mass center of the particle to act as a source of gravity. (For the mechanism how particles keep existing even outside the particle cluster they forged each other in, see my reply dd 17 oct to your comment on my essay). To me there is no pebble at its center which can act as a source, no interaction-independent something. Though the De Broglie waves then must refer to the energy exchange between particles and their environment and can guide them, these waves have no pellet-like source at their center. If what we call a particle is an oscillating piece of spacetime, a pure wave phenomenon, it can, of course, behave like a tangible, pellet-like thing: as time passes slower where the field is stronger, nearer its mass center, it offers an increasing opposition to a probe trying to penetrate the field. So if with very tiny fingers we would try to pinch the particle/field, we would feel spacetime become more viscous, more frozen in time, offering a stronger opposition as we increase the pressure, so it would feel like a tiny pea. The harder we pinch, the nearer to its mass center we get, the more violent its energy exchange is expressed as a counterforce to our pinching.

As there's nothing special to find at its mass center and these pilot waves are involved in the continuous energy exchange with its environment to keep existing, and even are part of what we call a particle, this two-way traffic is subject to manipulation. As the setup of the screen with the two slits and the machine gun in the experiment affects the directions of the energy exchange of the bullets (electrons) with their environment, interference effects are to be expected as this exchange is instantaneous, so in this view there's nothing in quantummechanics to get excited about. If the indefiniteness in the position of an electron depends on the distance it is observed from, by an observing particle exchanging energy with the electron, then to a distant observer the indefiniteness in the position of the electron is so large that it contains the experimental setup, so the electron is already partly behind the screen with the slits, the position of the particles of the screen and the slit edges being similarly indefinite. Hence Schrodingers cat, hence the entanglement of particles.

What is surprising is that so long after the discovery of the quantum nature of our world we still cannot let go of the antique particle idea which implicitly refers to objects having an absolute kind of reality, an existence outside interactions, as if they are created by some creator outside the universe and thus exist even without interacting to their creator. By clinging to classical, causal physics, by thinking about particles as pellets, we require something of them which they simply don't posess: an autonomous, interaction-independent existence, an individual nature of their own. This is why particles of the same kind are identical, so they the nature they have they owe to, maintain by mutually exchanging energy, their exchange with other kinds of particles proceeding in a different way -the how being the main question in particle physics. The pellet idea is related to the similarly naïve idea of spacetime as something which comes for free, as if, though deformable, it doesn't have properties of its own and doesn't need any work to keep existing. Though we're aware that spacetime is filled with virtual particles, spacetime to us is still too obvious a quantity to be able to concede that it is the product as well as the source of all particles that inhabit it, so we still tend think about spacetime as something which exists only to accommodate particles.

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Dear Arjen, dear Anton,

I hope, Anton is able to explain why the measurement by Gompf et al. with single photon counting is obviously wrong. You will find some further details in a corrected reply to Arjen at my thread 527.

Curious,

Eckard

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Hello Arjen,

1. Please quote me all you like.

2. When I said you were like Galileo, I wanted to indicate that the viewpoint taken on QM will determine if the model is understandable. The solar system is easily understood looking from the sun, it is difficult looking from the earth.

3. Your "Principles of Quantum Mechanics" wiki site and the animation of the vectors increased my knowledge of standard QM quite a bit. And it helped me understand how my work "Digital Wave Theory" differs from QM as it stands.

My concept of observables (for lambda-hopping particles) may be of interest to you. I mention it here because your reference caused me to notice it.

a. A particle can have both a position and time (from a local clock) as observables. However, velocity (translational and rotational) along with momentum and energy can never be observables because they can never be observed they can only be calculated by invoking measurements made in the past [Velocity = (X2-X1)/(T2-T1)]. Where X2 and T2 are the current position and time, and X1 and T1 are the previous position and time. Thus for me those Feynman spinning vectors may need to contain a little microprocessor and some memory:)

b. I am also thinking that this may explain the arrow of time? To get a velocity we have to reference the past from memory and thus time only moves forward.

I am always interested in what you think.

Thanks,

Don L.

5 days later
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It is daring for me to budge in a discussion between theoreticians of high order. Being an experimentalist and a low level empirical physicist, i find that it is we who make nature complex by the way we deal with it in bit and pieces. To me a particle's fuzziness in quantum physics and the wave packet analogy are not two different pictures. Classical analogs for quantum pictures need not describe reality, as Physics just deals with relative reality and not the absoluteness of truth. Uncertainity is the way of life as we live and it should be taken normally in Physics too. Once we understand the physics phenomena much more comprehensively, the theory will get simplified and unitarity will result out of duality/multiplicity. In fact the creation and evolution of the universe contains all the facets of Physics. Present day Physics was evolved without any study of the early universe and that is why we have ended with so many mysteries there by way of dark matter/energy, black holes and what not. Physics as evolved is literally not valid for the early universe of about first billion year starting with birth, which too is anamolous as per the Big bang approach. We are unable to say anything about what existed prior to it!

Thus, issues of classical and quantum Physics and their correspondence and reconcialiation are beyond us till we evolve an intermediate physics, such as has been proposed by Tejinder in this very forum as mesomorphic region where the planck constant can not be treated either as zero or its full estimated value. To put emphasis to this view, i refer to some isolated measurements done on the light signals coming from distant galaxies/stars , estimated to be 12 billion years away. The velocity of light has been measured to be distinctively higher than the accepted value of c. Similarly, the rato e/m has also been observed to be different. Thus, as we approach still closer to the birth of the universe, one may find further escalation in the magnitude values of such ' constants'. In fact, i conjecture that the value of Planck's constant itself may come out to be lower in the early universe. In short the physics of the early universe holds the keys to solving the riddles of present day physics as well in resolving the mysteries of the early universe. May i humbly indicate my essay in this forum as well as last year forum that indicate such possibilities and perspectives!

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Dear Arjen,

I feel a bit dense because you are claiming to make your, as I understood, dipole-like alias doublet-like needles understandable to a six year old child or a bar maid and I am not even in position to imagine what you meant by a dense field of other needles.

You certainly know: A doublet is the formal derivative of the Dirac impulse.

Since you used j instead of i, I guess you are familiar with the decrease of an electric field with increasing distance. Why do you favor the coexistence of both a local needle and a guiding wave standing or propagating (?) in 3D? What is wrong with the layman's guess outlined in my essay and M291 that wave and particle are the same merely seen from different perspectives as are for instance function of time and corresponding function of frequency? The latter would presumably be understandably to my grandmother when she was still alive.

Regars,

Eckard

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Author may consider the comments of Eckard and myself above and indicate his own response to the same. truth of physics is still beyond us all and only a widely open mind can provide us greater insights!

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I guess nn means Narendra Nath. I slightly disagree. I mentioned Galilei, Gold, and Ren. The latter is unfortunately not yet known to average physicists.

Eckard

5 days later
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Arjin,

1. The updated arrow animations on the wiki site are much improved.

2. It struck me that that Huygens wavefront propagation diagrams are very similar to the spinning arrows diagram of Feynman. It has a benefit? in that it actually shows the wave spread out in space. The arrow diagrams make it look like the arrows are in a straight line which are easier to sketch but hide some action.

Do you have any thoughts on Huygens vs. Feynman.

3. Your Blog is great promotion for FQXi and this contest.

Thanks,

Don L.

Arjen

I greatly appreciate your excellent work and approach, but have you yet visually transposed the mechanism to compound longitudinal pressure waves. I believe that will be the key.

Consider; The 'lateral wave' is just a mathematical construct, and representation on an oscilloscope, but not a 'real thing' in nature. It was forced upon us when the ether had to be removed. Now we know there IS a quantum field, and another possible answer NOT needing it to have no properties, we don't need to be tied by it any more and can look to reality.

Have you properly checked out the Discrete Field Model yet?

Best wishes

Peter

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Arjen,

I just saw your new document. Thank you for it. But here, I have a challenge for you. Reading this essay: http://www.fqxi.org/community/forum/topic/555 and their additional papers, I came in contact with a QM experiment, the so-called Hardy's paradox: http://en.wikipedia.org/wiki/Hardy's_paradox

Here is how it goes:

1. take an electron source, pass the beam through a 50/50 beam splitter, and recombine the beams with another 50/50 beam splitter with 2 outputs C and D.

2. adjust the arms of the interferometer in such a way that the intensity of C is 100 and at D 0% (C=constructive interference, D=destructive interference)

3. repeat steps 1 and 2 with a positron source

4. put the two interferometers close to each other in such a way that the right arm from the electron interferometer (R_e) touches the left arm from the positron interferometer (L_p).

Now here is the problem.

Consider the case where an electron and a positron are launched at the same time.

If the electron tales L_e branch and the positron the L_p branch, the positron will destroy with the interference pattern of the electron causing its detection at D_e. Similarly if the electron travels on branch R_e, and the positron on the R_p branch, the positron will be detected at D_p because the electron blocked the L_p and R_p interference causing a D_p click. Moreover, if the electron is traveling on R_e and the positron on L_p, the two particles will collide and generate gamma radiation with no clicks at any C or D detectors.

Finally, here is the paradox. Is it possible to have simultaneous detections of the electron at D_e and positron at D_p? QM says yes, classical mechanics says no. Any classical mechanics modeling would require for the D clicks that the opposite particle travels inside the inner arms of the interferometers. But when both particles travel on the inner arms, the particles annihilate each other and therefore simultaneous D clicks are impossible in CM.

Just like GHZ, this is also impossible to be modeled by classical mechanics. Ergo, QM cannot be modeled by CM.

Florin

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Arjen,

Sorry, I want to clarify something wrong in my earlier posting. If a blocking particle is in the inner arm, the other particle has 50/50% chances to be detected at C or D, not always 100% at D. But if the electron is detected at D_e and we introduce which path detection for the positron, then every single time we find the positron to be located in its inner branch. Same for the other way around.

Florin