Dear Ben,

Thank you for taking time to read my essay, although you did not have time to participate this year. Your previous edition essay was great, so I look forward to see you here next time!

Best regards,

Cristi

Hi Cristinel,

Does anybody know where the votes are going?

I plummeted many positions from last night when I had 68 ratings to this morning's 66.

Think it has happened a few times?

I've sent FQXi a message.

Best wishes,

Antony

Cristi,

Very nice work! I just rated it.

I found your essay while searching for something about Wheeler on Google. It led me to find FQXi website for the first time. Thank you!

Brian

    Dear Brian,

    Thank you for the visit, and for the attention given to my essay. I am glad my essay helped you find FQXi, since I just read your essay and I like it!

    Best regards,

    Cristi

    Cristi

    thank you for your kind comments on my essay! I read yours back in June and again, now. You have a wonderful, easy to read, informative and thought provoking essay, which I very much enjoyed.

    It's funny that we both make entomological analogies describing quantum experiments. Even though I have a little issue with yours. I think it should have been more fitting to have not either flies or dragonflies for quantum spiders to catch but an unusual for the macro world hybrid: depending on the type of the web the spider sets up to catch this weird thing, it may turn out either as a fly or a dragonfly, exhibiting an unnerving duality -- but it still is the same insect!

    Also, it was refreshing to read such a positive review of Wheeler's ideas. I saw various takes on his legacy, including the ones coming from the other end of the spectrum, where, far from a visionary, he was made to appear more like the 20th century physics troll. But I agree with you that we should be thankful for Wheeler's courage in presenting his provocative ideas, on which "the new generation of Einsteins grew up to change the face of modern physics".

    I see you pose a provocative question yourself:

    "If Wheeler was right that we decide the physical laws, by our very choices as observers of the universe, then, due to their important contributions to physics, he and his students are responsible for many preposterous features of our universe."

    Somehow, intuitively, perhaps and on a completely different level, there may be truth to it. I believe that it is not so much our thoughts but our deep-most feelings to which the universe responds. But, at the moment, this lies outside of physics studies.

    I do not quite share your idea that our universe is mathematical. Here I side with Leibniz who pointed out that only because one can always find a mathematical formula describing any random distribution, like in an ink blot, it does not prove that this distribution is governed by a 'mathematical law': "This means that there exists a law simpler than just listing all the facts, from which nevertheless all the facts can be derived." [I copied this Leibniz quote from one of the essays without keeping the reference, sorry] But this idea is very much in line with Wheeller's beautiful thought that a very simple principle may lie at the heart of reality, waiting to be discovered.

    I very much liked that in the end you brought up the ancient TaiJi symbol (those ancients knew and understood more about the world than many modern people care to admit, don't you think?) In TaiJi two opposites, 0 and 1, meet, interact and combine to generate the myriad of things.

    Well done :)

    -Marina

      Dear Jonathan,

      Thank you for visiting my essay again. I read your beautiful essay some time ago and I liked it. Good luck in the finals too!

      Best regards,

      Cristi

      Dear Marina,

      Thank you very much for the nice and detailed comments to my essay. If you liked mine half as much as I liked yours, that's fine! About the analogy with fly/dragonfly, I wanted to make it by using some shape-shifting entity, like larva/butterfly, but larvae couldn't fly! And most important, I didn't want it to be interpreted as if the shape-shift took place in contact with the spiderweb. Regarding the quote you mention, about Wheeler and his students being responsible for many preposterous features of our universe, I am not sure in what proportion it was a joke, or a serious statement, or something between: a metaphor describing the paradigm shifts initiated by them.

      You said "I do not quite share your idea that our universe is mathematical." That's fine, since, for example, I don't know if it matters whether a line is a line, or just a collection of points which happen to form a line! Important to me is that I expect an element of the collection to be on that line.

      Thanks again for re-reading my essay, and for delighting us with your beautiful one (which I hope it will go into the finals).

      Best regards,

      Cristi

      My congratulations Cristi.

      I'm glad you made the finals, and I think your essay will get high grades from the expert reviewers (after all, they are experts). I wish you luck but I don't think you'll need it, as you did an excellent job on your essay this year.

      All the Best,

      Jonathan

      Dear Jonathan,

      Thank you, and I am happy for you too! There are probably almost fifty finalists, (and many others interesting essays which are not in the finals), but I hope the expert reviewers will find the time to give them all the deserved attention. I wish you success with your essay!

      Best regards,

      Cristi

      Thank you Cristi for your sweet reply!

      And congrats on making the list. For my part, I'm there not on the merit of my entry but because the 'thumbs' were bombing their competition and so pushed many of the best essays bellow the cutoff point, while mine innocuous entry remained under their radar. I already asked for permission to swap my place with one of those unfairly slighted essays.

      I returned here to further discuss your fly/dragonfly analogy. It is very clear to me now that we do not understand light. Neither do we interpret it right => hence paradoxes. Regarding my slight change of your analogy, won't you agree that with a single even if weird insect -- rather than 2 types of insects -- there is no paradoxes in either a plain double-slit nor a delayed choice experiment. I.e. we are observing the same phenomenon through different means and so we see its different aspects. But this means that nothing changes retroactively. Do you agree?

      Again, congratulations for making the list. Your essay is a good read for SA. Let's hope it gets there,

      -Marina

      PS Oh! and regarding your take on Wheeler's PAP -- every joke has some truth to it. I've seen people taking his PAP very seriously. I also see PhD's taking Copenhagen interpretations very seriously (as in 'this is IT' rather than just 'Bit' based on lack of better info). So, on the last day of the contest, having read so much that day, I could not longer be sure how you meant it. I thought you were joking when I read it the first time but must have lost my sense of humor by the time I read it again :)

      Dear Marina,

      Thank you for visiting my page even after the competition is ended, this is very kind. But of course nothing can be kinder than your proposal to swap your place with a less fortunate. Let me tell you that had you withdraw your essay after the votes ended, but before deciding the finalists, the finalists would have been the same (except yours). Because the tie at 4.3, the number of finalists exceeds 40. So I don't think that if you withdraw now, the position will be filled by the next essay, but you can try. Personally, I don't want to check now what is the next essay, but I would like yours to stay in the competition. And I think you deserved the good rates. See that only one FQXi member had to be added in the finalist's list, this shows that the community appreciated good essays, despite some attempts to self-promote by "the representants of the next revolution in physics", by downvoting "the defenders of the evil establishment".

      About complementarity. If you allow the particle to morph just before being detected, according to the property you measure, this doesn't quite resolve the weirdness. In the delayed choice experiment with the mirrors, one possibility is that the photon traveled both ways, and the other that it traveled along one of the paths. If we allow it to morph, then this means that it can teleport from one path to the other. So then, we have to admit teleportation of this sort (which is not the same as what goes by the name of "quantum teleportation"). For the sake of the argument, say we admit this too. Then, another problem appear. Let's think at the first mirror, the one doing the splitting. If the photon passes through, the mirror is not kicked. If it is reflected 100%, the mirror is kicked. If it is reflected 50%, the mirror is half-kicked. The delayed choice of whether to keep or remove the second beam splitter affects the existence of the kick in the first mirror. But the kick/not kick already hapened. So here is the mystery, that can't be removed just by allowing instant morphing. Also, how would the instant morphing explain EPR, without assumning the "spooky action at a distance"? All these are predicted by Schrodinger's equation, the mystery appears when we try to tell the story in a local manner.

      Best regards,

      Cristi

      5 days later

      Dear Cristinel,

      thank you for replying to my post, even though the competition is over. I appreciate your diplomatic way of putting "the representants of the next revolution in physics" vs "the defenders of the evil establishment." lol I'm afraid I'm not that diplomatic. I got the reply from the organizers that I may not substitute my entry for a 'better qualified essay'. I guessed this would be the answer when it was taking long to arrive. I see now that this could make some people question 'why this particular essay and not some other'. Now I hope that, looking for good entries, the judges would go down the list as far as 4.1.

      .

      Regarding light, I am afraid what I meant to say was that the whole paradigm with 'particle' vs 'wave' is in deep trouble. Especially the 'particle' part. The reason I liked your quantum spiders analogy so much (with my slight modification) was because it allowed to let go of old analogies and --even if for a moment-- take a fresh look at the old problem. And 'particles' is just another analogy (more on this later).

      Here is how Wheeler's delayed choice experiment could be translated into you modified by me model:

      Once upon a time, a weird quantum insect flew out of its nest and, having traveled for millions of years, was caught by a very hungry quantum spider, who had not eaten a thing since last week when it hatched. To catch its prey, the spider used a specific net designed to reveal a particular aspect of this weird thing; and the net could make it appear as if it was either a fly or a dragonfly, but, regardless of the type of net the spider used and how the thing turned out, it was still the same insect.

      See? There is no paradox.

      The paradox comes up when we speak of 'particles', which, to me, indicates that that the model does not quite work here. If we examine the history of how this particle idea came to occupy such a prominent place in quantum theory, ruffly: it began with Newton and, having proved to be very useful in several areas of physics, went through its ups and downs in importance until it was first revived and then promoted to the central role by quantum mechanics.

      So, when you say, "one possibility is that the photon traveled both ways, and the other that it traveled along one of the paths" -- what is this description based on? What if entirely something else is taking place that accounts for the observations?

      The trouble with 'particles' is that they are dimensionless points in empty space, while the real phenomenon appears to be some dynamic configuration of the medium we call space (in other words, you cannot extract it from the medium it is in). We do not quite understand this dynamic configuration; and this causes us to come up with strange ideas, which, in turn, lead to paradoxes. The famous Feynman's phrase about the quantum weirdness notwithstanding, the paradoxes are the symptom of the model not being right -- as in not right for a the application at hand. And I understand that people get attached to a model -- unduly so, if they have invested a lot of time and effort into it. Still, I don't see how the quantum theory can advance with this old, riddled with paradoxes particle model in place.

      In my understanding of these experiments (and I hope it's right, else please correct) photons do not interact with each other, but only with electron clouds of the 'material things' represented by the mirrors, or the screen with slits, or the detection screen, or the array of snooping devices aimed to detect which path a 'particle' took, etc. The important thing here is to remember that observation of a 'particle' constitutes placing some 'material' obstacle on its path, (which, naturally, affects it).

      Again, when you wrote, "If you allow the particle to morph just before being detected" -- who said anything about morphing? That too is an assumption presumably based on the Copenhagen interpretation. That too is just another analogy.

      I sincerely hope you would answer my questions, because.. ..cause I really would like to know :)

      Thank you,

      -Marina

      Dear Marina,

      I fully agree that particles are not points. They are wavefunction, state vectors in the Hilbert space. It may happen that the wavefunction is concentrated at a point, but this can be only for an instant. So the point particle representation wouldn't help here. When we measure some properties, only some of the possible states have that property. So you are right to say that, no matter whether we measure flies or dragonflies, it is the same insect. Because a wavefunction which has the property named position well defined, can morph into one that has the momentum well defined, although these are complementary properties. So, from this viewpoint, I agree that there is one insect, which can turn out to be of one kind or another. On the other hand, there is a reason why I emphasized the distinction between flies and dragonflies: I think that the delayed choice experiment shows that the photon already was either in a "both-ways" or a "which-way" state, when it reached the first half-silvered mirror. If this is not convincing, think at another version, called the quantum delayed choice experiment. In this experiment, we can delay even the decision of whether the second half-silveerd mirror is present, and maintain this choice in a superposition for an undetermined time.

      My point of discussing the delayed choice experiment was that its conclusion is, in my opinion, different than Wheeler's, which is that "it" doesn't exist except through the "bit" we observe. My proposal is that the wavefunctions are real (ontological, not only epistemic), unitary evolution describing their evolution is not broken, but the initial conditions are not fixed yet completely (delayed initial conditions). But each measurement fixes them more and more. Nonlocality and the apparent backward causality exhibited by some experiments show in fact that Nature reserves the freedom to choose the initial condition at a later time, and does this partially with each new measurement. While this may seem strange, in my opinion explains the weirdness of quantum mechanics. Moreover, it become less strange, if we think in terms of the 4D block world, as in relativity, and we realize that global consistency principle has to hold.

      Now, I think that various interpretations can tell the same story in different ways. The one I propose makes more sense to me, but I would not exclude the possibility that for others, other interpretations make more sense. And maybe one interpretation is more helpful than another, for a particular problem. For instance, I am most interested in having an ontological interpretation which doesn't violate unitary evolution, and in the relation between relativity and the quantum.

      Best regards,

      Cristi

      Thank you Cristi for your elucidating reply!

      The arXiv paper you linked makes a wonderful illustration, even though they too say a photon 'morphs' between "particle" and "wave" depending on how we 'look' at it. But why would it morph rather than perhaps being already something in-between or both?

      See, I'm trying to look at a photon as a disturbance propagating through space, and, doing so, I look at the experimental area as a whole from the POV of the dynamic structure of space that 'wants to be empty' locally. Then whatever disturbance enters a locality is expelled into the direction that gives. 'Measuring' or 'looking' introduces another disturbance into this setup area, which affects how the preexisting disturbance behaves.

      I am only trying to understand this mysterious thing we call space ..and light. I am perplexed trying to explain the most mundane experience of seeing within the current scientific framework. ..and to me it appears that neither 'wave' nor 'particle' are appropriate models for light. Here is why:

      When I look at the world, what I see are the photons registered on the retina of my eyes. Back in the XV century Renaissance artists realized that straight streams of light converging on a point of view were responsible for the appearance of the perspective and the illusion of depth on a flat canvas -- it's all pure geometry. But. In reality, the same streams of photons are coming from everywhere, from all directions at once. If photons are particles, why would not they bounce off each other and scatter? And if they are waves, why would not they interfere and thus change their form before reaching my eyes? In other words, how come I get to see such a clear picture? I know that, within the current scientific framework, photons do not interact with each other and that should be enough to 'explain' this. But... somehow this does not explain it, really. Something crucial seems missing -?

      In this regard, I was wondering if you knew about the experiments that involve 3 streams of photons along the x, y, z directions, focused at one point, and, after crossing this point, made to go each through their own screen with slits -?

      Thank you very much for your reply and I am still trying to understand what exactly you mean by wavefunctions being real ontologically and not just epistemically. The best I can do is to imagine them as underlying quantum processes that govern the dynamic structure of space -?

      Thanks a lot,

      -Marina

      Dear Marina,

      We agree in several points. As you observed, photons are not point particles, and they don't bounce, they pass through one another, without interacting, indeed. I am not aware about the experiment you mention, but I think that the three streams of photons don't "see" each other. The fact that photons pass through each other undisturbed doesn't contradict interference, in fact interference wouldn't be possible without this. The problem is that, if after interference, you detect the photons, they are found in positions distributed according to the Born probability obtained from the wavefunction which resulted from interference. It is as if the wave, initially widely spread, concentrates at the point where it is found. As I said earlier, when you measure position, you find the photon localized around a point, but this doesn't mean it is point particle, but just a localized wave. So, the wavefunction before observation is epistemic, it gives the probabilities, and after the measurement, it is ontological, it is what you find. There are more ways to consider the wave to always be ontological. The most direct way is to consider that, just before being measured, it changes its shape, to become an eigenstate of the measured observable. This picture is like this: (1) The wave is ontological. (2) It evolves unitarily between measurements. (3) At measurement it is projected, according to the projection postulate (and Born's probability). This is probably close to your idea of shape shifting. It explains some features, and if this answers all of your questions, it may be what you want. It is not very good when you try to think how this applies in spacetime, especially when entanglement is involved, but it challenges one's intuition even for only one particle (by particle I don't mean point particle). For some, this picture may be sufficient, for me is not. It may be just a matter of preference after all. I explained 5 years ago some of my reasons why I am not happy with it, and what I proposed in place, in this video, and this article. I hope this will help.

      Best regards,

      Cristi

      Dear Cristi,

      thank you for your reply! I watched the video and looked at your paper. You have a beautiful voice :) even though some whistles were introduced by the loss of resolution.

      I really appreciate your feedback on my thoughts. You wrote: "The fact that photons pass through each other undisturbed doesn't contradict interference, in fact interference wouldn't be possible without this."

      But.. in the double-slit experiments, the interference is the result of diffraction of light streaming through the slit -- the photons bounce off the electron clouds (or weak magnetic field) of the screen material. And it seems that a weak polarization also takes place -? That's why a precise setup is required between the wavelength, the width of the slits, the separation between them, and the distance to the detection screen, on which the interference itself is produced.

      Artists have long noticed this weak diffraction/polarization of light along the edges of the objects. Being mindful of it is what makes an object in a still life appear voluminous and integrates into its surrounding rather than appearing flat against background.

      So, in my understanding, there is no interference between the photons themselves. There is interference between the photons and the weak magnetic fields (electrons) of the material objects. Otherwise, if photons, streaming from all directions, interfered before reaching my eyes, then the forms of their waves would be modified; and a modified light wave implies at least a different color or its intensity -- but nothing of the sort happens, nothing undulates or shimmers, and I see clearly -?

      Again, in my understanding, the waves of the same kind and frequencies do interact with each other, don't they? But light in empty space does not seem to (at least, not until it reaches the detection screen).

      Thank you very much on your feedback, I value it a lot,

      -Marina

      Dear Marina,

      Yes, in the double slit experiment, diffraction is required. Diffraction is just light moving around obstacles, and this can be understood by Huygens's principle (every point on a wavefront is a source of a new wavelet, and all wavelets combined give the wave), and not by bouncing. According to this principle, wavelets travels along various paths, most of them curved, although when we add them, we obtain that light travels in straight lines. Diffraction appears when in the sum of the wavelets part of them are missing (when obstacles are present), this is why in diffraction light doesn't go straight.

      On the other hand, interference is just the superposition (addition) of the waves. When two waves interfere, we add the amplitudes at each point, taking into account the relative phase. This is why I said interference is not interaction. Waves combine their strength at each point, but they don't interact. So, when you say "So, in my understanding, there is no interference between the photons themselves. There is interference between the photons and the weak magnetic fields (electrons) of the material objects", you surely mean "there is no interaction between the photons themselves". Also, you say "Again, in my understanding, the waves of the same kind and frequencies do interact with each other, don't they?". They don't interact. The fringes observed in the experiment are not due to interaction, but to superposing the two waves.

      Best regards,

      Cristi