Dear Inger,

No, it is only the mass. If you take a look at some of the recent publications on molecule interferometry (Gerlich2011, Nat. Comm. 2, 263), then you can find that the molecules are already very complex. However one finds always the maximum predicted quantum visibility in interferometry experiments. So why is that so? First, what we observe is single particle interferometry otherwise it would hardly be a quantum experiment. Roughly speaking this means every particle interferes only with itself and this is per definition identical - that is what we mean when we say we probe quantum superposition.

So then you could argue that other properties of the molecule play a role: internal states such as rotation, vibration or the conformation of the molecules, but again we don't see any indication in the experiments that those properties influence the centre of mass motion. These internal molecular properties are simply not coupled to the motion of the particles. This means in matter-wave experiments only the mass of the particle and they propagation speed is important. Both speed and mass define the de Broglie wavelength of the particle.

There is of course a dependency on particle mass distribution and that comes from the fact that you have to sum many single particle interferometry event to observe a nice interference pattern as for instance in Juffmann2012 [Nature Nanoscience, 2012]. As the interferometer is sensitive to a narrow band of particle de Broglie wavelengths one needs particles of almost the same mass to collect a nice interference pattern. This is taken care of by chemical purification of the molecules after synthesis and also by mass-selective detection with a mass spectrometer in the present experiment. But again this mass dispersion is not a fundamental limitation for molecule interference experiments; it is a technical issue. The question we ask with such experiments is if there is a fundamental reason for the quantum to classical transition - something we cannot overcome by technology.

Regards,

Authors

Dear Dr. Kadin,

Thank you for your comments and for your intriguing essay. Experiments which perform matter-wave interferometry with atoms and molecules as large as fullerenes already establish their wave nature and the validity of superposition for them [e.g. please see arXiv:1204.4325]. We wonder how your proposal can be made consistent with these experimental results?

Regards,

Authors

Dear Armin,

Thank you for your comments, and good to see your essay here.

Regards,

Authors

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Hi Tejinder,

Can you point me to information on testing particles for interference (that I would understand)?

In the essay (http://www.fqxi.org/community/forum/topic/1403) I logically derive the Planck mass (via two methods) as the ultimate mass for a particle. This does not mean there are any particles in nature that can make it to this mass. I define particle as an object with mass that shows the property of interference. It does not surprise me that real particles never get close to the Planck mass.

This is why I was interested in diamonds. They are peculiar because they are hard crystals that are thought to be quantum mechanical at all sizes. I think they have a chance of getting close to the Planck mass.

Let me know what you think,

Thanks,

Don L.

Dear Authors,

Thank you for an interesting essay.

Maybe I am missing something, but, on the face of it, there may be some contradiction between the following statements in your essay:

1). "When one considers doing such an interference experiment for bigger objects such as a beam of large molecules the technological challenges become enormous."

2)."However when we look at the day to day world around us linear superposition does not seem to hold! A table for instance is never found to be `here' and `there' at the same time. In other words, superposition of position states does not seem to hold for macroscopic objects. In fact already at the level of a dust grain, which we can easily see with the bare eye, and which has some 1018 nucleons, the principle breaks down."

So if technological challenges are enormous for large molecules, one would think they are downright prohibitive for dust grains or tables, so the principle does not break down, but we just cannot solve the technological challenges to demonstrate it for such objects? The following analogy may be appropriate: we cannot demonstrate reversibility for large objects (e.g., when we break a vase), furthermore, thermodynamics is based on irreversibility, but that does not mean that reversibility fails for large objects.

Another remark. For what it's worth, I expect interference to exist for arbitrarily large objects. My reasoning is based on the following almost forgotten ideas of Duane (W. Duane, Proc. Natl. Acad. Science 9, 158 (1923)) and Lande (A. Lande, British Journal for the Philosophy of Science 15, 307 (1965)): the direction of motion of electron in the interference experiment is determined by the momentum transferred to the screen, and this momentum corresponds to quanta (e.g. phonons) with spatial frequencies from the spatial Fourier transform of matter distribution of the screen. So I tend to make the following conclusion: when the mass of the incident particle increases, the momentum transferred to the screen remains the same, but the angle of deflection of the incident particle becomes smaller, as its momentum is greater. So the mass of the incident particle is in some sense an "external" parameter for the interference experiment.

Thank you

Best regards

Andrey Akhmeteli

    Dear Andrey,

    Thank you for your comments.

    There is no contradiction actually. When doing an interference experiment with a large molecule, one overcomes the technological challenges to prepare an initial superposed state, and then essentially one waits and watches. If quantum theory is right, the superposition will last forever, an interference pattern will be seen, and indeed it will have been shown that the observed absence of superpositions in daily life is because of practical limitations. On the other hand, if CSL is right, then the superposed state which one has prepared after overcoming the technological challenges will not last forever, and interference will not be seen. This would mean that the absence of macroscopic superpositions is not because of technological challenges, but because of new fundamental physics to which quantum theory is an approximation.

    With regards,

    Authors

    Dear Don,

    Please have a look at this review:

    http://in.arxiv.org/abs/1109.5937

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    Hi, Post above was by Don Limuti, and not anonymous. Time-out got me.

    • [deleted]

    Hi Tejinder,

    Thank you. http://in.arxiv.org/abs/1109.5937 was very good. There is a lot of "art" and science in these measurements.

    Here is conclusion of my essay:

    Particles can never be accelerated to "c" because they hit their respective Vmax values first and can not be accelerated further. This is because particles are characterized by their Compton wavelength and at Vmax the Compton wavelength has shrunk to the Planck length, as short as anything can get. The Lorentz contraction (1-v2/c2)0.5 seems to indicate that that the velocity of a particle v can be taken to c but as shown in this essay it can only be taken to Vmax just short of c. Say goodbye to the elephant.

    At Vmax all particles:

    a. Have the same Compton wavelength which is the Planck length.

    b. Have the same mass which is the Planck mass.

    c. Have a Lorentz contraction that is equal to m0/Pm

    d. Have a Schwarzschild radius that is two Planck lengths.

    My contention is that quantum mechanics ends at the Planck mass. This does not mean we can find particles that have this super mass. This is why I am interested in diamonds and your essay which explores this most interesting mass zone from the Buckyball to the Planck mass. I suspect that a diamond with a mass below the Planck mass will show interference and a diamond above the Planck mass will not show interference.

    Check out the logic for yourself: http://www.fqxi.org/community/forum/topic/1403

    Thanks again,

    Don L.

    Very interesting and clear. Your proposal seems to solve many very difficult problems at the foundation of quantum theory. I wish you luck in the contest, and above all, in the development of your research programme.

    Best Regards

    Daniel

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      Dear Authors:

      Thank you for responding to my comment, but you have missed the key point which is at the heart of the quantum paradoxes. The quantum diffraction experiments (all referenced in my essay) are obviously correct, but their interpretation is based on an assumption that is incorrect. As described in my essay, and referenced to the work of Van Vliet, the scattering of a neutron requires a quantum transition of the crystal, which in turn requires a quantized momentum transfer to a degenerate phonon with momentum hG, where G is a reciprocal lattice vector. This gives rise to the classical wave diffraction result, but does NOT require an incident coherent wave. The same is true for an atom, molecule, or buckyball. They are all localized particles, not extended phase-coherent waves. (This is in contrast to electron and photon waves, which really are extended coherent waves with linear superposition.) I realize that this is heresy, but that is exactly the point of this FQXi essay contest - to question assumptions that no one ever questions. Please read my essay more carefully. I have taken great pains to explain everything clearly and consistently. I would be happy to discuss this offline, if that would be appropriate. My email is given in my bio.

      Alan M. Kadin, Ph.D.

      • [deleted]

      Dear Alan Kadin,

      "The FQXi contest would seem to be an ideal venue to explore such concepts, but this has drawn relatively little attention."

      Perhaps you meant the attention to your essay rather than to the contest. Be sure you explained your remarkable result clearly, consistently, and understandably enough as to persuade any unbiased reader. Your essay was the only one that I called more convincing than quantum logics while everybody so far called my essay overly critical.

      I hope, those who read uncommon or even heretical ideas will memorize them and eventually be in position to judge independent of the crowd.

      Concerning the discrete vs. analog or linear vs. non-linear issue I would like to iterate what I tied to make aware of in the previous contest where it got unnoticed among more than 400 posts:

      Cosine or Fourier transformations are non-linear integral transformations that render a continuous function of (elapsed or anticipated as elapsed) time into a discrete function of (likewise positive) frequency and vice versa.

      Regards,

      Eckard

      Please:

      I show by experiment in this essay contest how quantum theory is an approximation. My experiments refute the Born rule. A singly emitted gamma-ray should go one way or another at a beam splitter, but I show coincident detection exceeding chance. Similarly for an alpha-ray. This supports the Loading Theory, which was misrepresented and misunderstood for ~70 years, which is why no one considers it. There are two problems:

      (1) There are accepted experiments that may be adjusting things to favor QM, and also that researchers have not looked for certain artifacts. A good example is macromolecule diffraction. I do not expect a macromolecule could load up. My experiments and analysis indicate the universe is not crazy and that macromolecules are real particles. But atoms can take on either a wave state or a particle state. My enhanced version of the Loading Theory can explain wave-particle duality up to at least atoms. Physicists may think a macromolecule is neutral, but it is easily charged. It is very likely that many experiments are looking at field deflection effects. To further back my claims, I analyzed one of the Vienna experiments in my essay, and cite several anomalies that do not fit diffraction theory.

      (2) The other problem is that my work is so sensational that you are not likely to take it seriously unless other physicists examine it. I have been offering to demonstrate to physicists for 10 years and have performed public demonstration of the gamma-split experiment with little recognition. What I have is for-real and I go with full confidence to face any scrutiny. I made an offer to demonstrate to FQXI people in Brendan Foster's blog on the essay contest.

      Please be careful: I do not need to be the one to say bad things about physicists who embrace quantum weirdness because they are invested in it. Now we have a good experimental reason to resolve the paradox instead of embracing it. The history that has misled generations of physicists is in my essay. We no longer need acts of desperation, like superluminal magical collapse of the wave function, etc.

      Please see A Challenge to Quantized Absorption by Experiment and Theory. Also please see Ragazas' paper that supports the Loading Theory.

      Thank you, Eric Reiter, September 12, 2012.

        Dear Angelo, Tejinder, and Hendrik,

        You present a very good idea, all the more so because of the very realistic possibility of experimental verification in the near future. I don't know if it's right, but the case you present for pursuing this direction is quite convincing. Indeed, I hope it's wrong, because it would wreck some of my own ideas about quantum gravity! The universe is oblivious to such considerations, however. A few questions and comments:

        1. Presumably this provides an arrow of time, since collapse is irreversible, but perhaps time in this sense fades out of the picture on the fundamental scale where the superposition lifetime becomes infinite?

        2. I'm sure this has been addressed, but it seems that there might be some issues involving things like locality and "microscopic constituents" of "macroscopic systems." Roughly speaking, how does a microscopic system "know" if it is supposed to preserve its own superposition or recognize that it is part of a larger system, which must collapse? One of the main points of the decoherence explanation of the measurement problem is that one must consider microstate, apparatus, and environment simultaneously. I am wondering how this all fits together.

        3. You mention Adler's view that it's the wrong approach to quantize classical dynamics. This may be correct, but it seems to me that it is simply a choice of assumptions: does one start with the correspondence principle, in which case classical physics is viewed as a limit of quantum theory, or does one start with the superposition principle, in which case quantum theory is built up from classical alternatives? Perhaps the experiments you mention will settle this one way or the other.

        4. I will have to look at your reference by Oreshkov et al., to see exactly what they mean by "order." Again, this might wreck my own ideas if it is right.

        5. I don't expect that you will agree much with my own approach, but if you're interested to see the motivation for my questions, my submission is here: On the Foundational Assumptions of Modern Physics.

        Thanks for the interesting read. Take care,

        Ben Dribus

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          Dear Dr. T P Singh,

          Thanks for your beautifully written enchanting essay. It contains up to date information on QM and its various versions. I, too, have my own version of QM and to know this,please, go through my essay (http://fqxi.org/community/forum/topic/1543--Sreenath) and express your comments on it in my forum. It is continuation of my last year's essay.

          In your essay, you have expressed your views with crystal clarity and also proposed an experiment to verify it. However, I feel that, currently there is lot of confusion in distiguishing between the classical world and the quantum one. This confusion,it appears,has arisen as a result of the failure to realise the seperate fundamental traits laying behind both worlds. If we realise this dichotomy then the results of your experiment become obvious before conducting it.

          Best regards and good luck in the essay contest.

          Sreenath

            Dear Tejinder Singh and collaborators

            Thank you for your essay, which presents a lot of material completely new to me. We seem to be thinking on the same lines.

            I tried to describe a possible form for the kind of nonlinear theory which you suggest. It starts from the notions that

            - space-time may have an asymmetric metric $g$ and an asymmetric connection $\nabla$.

            From the metric, one can derive (at least) two interesting algebraic features. One is a model of the complex numbers, so $i^2 = -1$. The other is an element $R$ of a Hopf algebra discovered by Dubois-Violette and Launer. $R$ satisfies the "Quantum Yang-Baxter" equation.

            $g$ and $\nabla$ are constrained by insisting that

            - $\nabla i = 0$ and $\nabla R = 0$.

            A solution is a pair $(g, \nabla)$ for which

            - the Yang-Mills functional is stationary under all small variations of $g$ and $\nabla$ for which $\nabla i$ and $\nabla R$ are stationary.

            There are other variants of this model.

            A "particle" is a basic solution, an eddy in the geometry of space-time.

            I have no evidence that real physics is like this, but it seems to offer all the apparatus one would expect: variational calculus, Hopf algebras. It fits naturally with general relativity. Solutions $(g, \nabla)$ may form a smooth manifold whose tangent spaces are the Hilbert spaces of quantum mechanics. If so, it seems likely that superpositions of states are unstable, as you suggest.

            I would be glad to hear any views you may have on all this.

            Best wishes

            Alan H.

              Angelo et al.

              Fascinating essay. I disagree with proofs of Bells inequalities but that does no affect the substance, and I agree Optomechanics and Trace Dynamics, both consistent with my own fully mechanistic approach to causal unification, using a " radical rethink of how we comprehend quantum theory, and the structure of spacetime."

              I suggest matter can be superposed in terms of additivity, i.e. fluids. Fine sawdust is additive, and at a larger scale 3 billion tables may be equally additive.

              Have you considered superposition as long term macroscopic evolution subject to binding energy, so rigidity (viscosity) is the key variable?

              And ref the twin slit molecular results; Have considered that molecules may propagate photons on surface interaction at the dense surface electron fine structure slit edges?

              I've been discussing a simple causal re-interpretation of the measurement problem and the Copenhagen interpretation based on the mechanism of detection as 'sampling' and modulation discussed in my essay. I hope you'll get a change to read and discuss.

              Best wishes

              Peter

                Thank you Eric for your remarks. We are trying to understand your essay and the one by Ragazas.

                Regards,

                Authors