Dear Professor D'Ariano,

In your view, as I understand it, the fundamental existents are neither particles nor fields. Even space-time is not ultimate. Instead, reality would seem to be a type of abstract mathematical structure. You emphasize, however, that the base of reality is a particular structure which follows precise and definite rules, as opposed to a generic structure.

This picture of things raises the following question: Is reality at bottom only a mathematical structure, or is reality a non-mathematical thing which exemplifies this structure? If reality is only a mathematical structure, then it is natural to wonder what distinguishes the one real structure from the infinitely many structures which are unreal. On the other hand, if reality is a thing-in-itself, or things-in-themselves, exemplifying these structures, then there is a different question, but still an important one. In this case, it would be reasonable to ask what else we could infer about the thing-in-itself, beyond the fact of its existence. Perhaps even the word "existence" would be too definite a term here. It would be uncomfortable, although perhaps unavoidable, to have to postulate something so unknowable. These questions are not really objections to your view, but they nonetheless would seem to be puzzling consequences.

Laurence Hitterdale

    Hi Mauro,

    > What you call the "explicate" order is the classical information that we can tap from the quantum automaton, whereas the "implicate" order is the secret quantum information precessed by the automaton.

    Yes exactly.

    > I also had a read of your essay, and I found it very clearly written and with interesting ideas inside (and I rated it high), though I'm not completely sure for the moment that I share the "Bit from Us" part of your thesis.

    I think the important thing for now is to show that the computational paradigm is feasible and has explanatory power. Once we have such a model for how the physical world arises, then we can see if it answers questions about what lies underneath the physical.

    Hugh

    "One can ask: what is the minimal field vector dimension s of a nontrivial automaton quasi-isometrically embeddable in R3 and isotropic?"

    Did you read about the part in the introduction that the essay should be interesting to the educated public along the lines of an article in Scientfic American? I'm MIT educated and that's total word salad to me. Am I supposed to know what "R3" is?

    These essays are to be rated according to relevancy and interest. I have plowed through several essays this evening hoping to find one which was relevant and had something to do with whether reality can be represented digitally or whether reality doesn't rely on digital bits. I have also been hoping to find one that was interesting enough that it would deserve more than a skim through. I have yet to find one. They are all like this essay - which seem to have something vaguely to do with "information", but nothing to address Wheelers dream of a completely digital representation of the world.

      Greetings Giacomo,

      I greatly enjoyed your essay. I find the notion of a quantum cellular automaton quite compelling, and your formulation shows great promise. Simple and elegant. I first heard the term "It from Qubit" attributed to Paola Zizzi (isn't she also at Pavia?) by Lloyd and Ng in a Scientific American article, and this certainly makes more sense than "It from Bit." Her work inspired me and she encouraged me to pursue my Physics studies, a number of years ago, and I'm wondering if she was one of your inspirations as well.

      I'll ask you the same question I asked Gerard 't Hooft about his CA based Quantum Gravity theory at FFP10 - as recounted in my essay - in your theory "What does the computing?" And based on what came out of that conversation I should also ask "Is your Quantum CA Lorentz invariant?" because Gerard said this is very difficult to achieve with CA based theories. In any case; I have rated your essay highly, and I wish you the best of luck.

      Have Fun,

      Jonathan

        Best of Luck for the Magnificent Eight !

        I am throught the 180 essays, all rated. For me 2/3 of them were poor and other 1/6 curious. The rest (1/6) have I rated over 4/10.

        You are among the authors of the top essays from my sight - alphabetically :

        Corda, D'Ariano, Maguire, Rogozhin, Singleton, Sreenath, Vaid, Vishwakarma,

        and I hope one of you will be the winner. (Please, don't rate my essay.)

        David

        Yuri

        I read your essay. Yes, I found your empirical law for masses interesting, but we need at least a rough reasonable motivation for it. Don't you think?

        My best regards

        Mauro

        Dear Dr. Laurence,

        thank you for your provoking post.

        For me "reality" is definitely not a mathematical structure. You should specify better what you mean by reality: if reality is what you see (the shadows on the Plato's cave) or what you believe is out of there (the bodies projecting the shadows). In my essay I clearly stated that the main point in the scientific method is to clearly distinguish between theory and experiment. Such a distinction, far from being trivial as it may appear at first sight, is in my opinion the main reason for the stubborn attachment of many scientists to the view of space-time as "a stage where particles move"--a theoretical landscape that has been proved to be foundationally inconsistent, and it is the origin of the apparent paradox of the GR-QT conflict. We are taking about "theory" here, namely what we believe is out of the cave, the mechanisms by which we explain what we see. But what we believe is not what is "actually" out there (this is a nonsense: who is the Referee to assess reality of what we believe?) We shouldn't forget that we are the ones that build-up the "ontologies" as convenient tools for reasoning.

        Now, at this point, you should agree that what we are talking about is "theory". And theory is written in the language of mathematics. Therefore, it is not "reality" that is an abstract mathematical construction.

        Thank you again for the opportunity given to me by your post

        Mauro

        Franklin

        I am surprised that at MIT students don't know what is R^3. Even in Italy at high schools students know it! Besides, I clearly defined R^3 in my essay as "the usual Euclidean space", and I personally studied Euclidean spaces at a Literature high school. I have many friends at MIT since ages (and even got my PhD students having a postdoc there), and you do not seem a standard MIT-educated person. You are just kidding.

        Anyway, talking more seriously. I wrote an essay deliberately with many levels of reading, to satisfy all different kinds of audience. I devoted only one page to the technical level, and used the most standard notation and most elementary notions. (Every science-graduated should know notions as field, dimension, metric, isometry, isotropy. Maybe he is not required to know GR, but he definitely must know the basics of quantum theory.) Having in mind the possibility of a Scientific American publication, I also put the technical part between definite boundaries within the essay.

        If we want to talk about serious real physics here--not mere random speculations--at least, there must be a page giving the precise technical definitions. Not only this is allowed by the rules of the contest, but also it is logically mandatory. Otherwise, one can e.g. claim gravity as a force between dipoles, forgetting that it would not go as the inverse square law.

        Paradoxically, the Corda paper (which is not an essay, but a technical paper that needs a long list of references to be read) found the consensus of the Community. Therefore, it seems to me that not only you are not a standard MIT-educated person, but not even a standard member of this Community.

        I understand your frustration.

        Don't worry, be happy

        With my best regards

        Mauro

        Dear Jonathan,

        thank you for your beautiful compliments. I know Paola Zizzi, but I didn't know that she used the "It from Qubit" modification of J.A. Wheeler's paradigm: it has been so natural to me for years. Paola is not in Pavia, she is in Trieste. I also know Seth well, I will ask him. Seth inspired me a lot in these last years.

        It is interesting that Gerard 't Hooft said that Lorentz covariance " is very difficult to achieve with CA based theories". This makes my result stronger. The fact that I achieve Lorentz covariance is a tautology, since the quantum automaton leads to Dirac! And, the fact that the automaton has been derived without using SR makes indeed the result striking. But the point is that--as also explained shortly in my essay and proved in full extent in Ref. [7]--Dirac equation and Lorentz covariance are obtained in the relativistic limit of small wave-vectors (here small means compared to the Planck ones, namely huge!). For ultra relativistic and/or Planck regimes there are distortion of Lorentz covariance a la Smolin/Maguejo and Amelino-Camelia, and there is a full range of physics, from the Planck scale to the macro. The fact that Gerard cannot achieve Lorentz covariance is because his CA is classical! Right, you need quantum superpositions to recover continuous symmetries from the discrete. Paradoxically quantum theory is needed to recover SR! (I say paradoxically, in view of the GR-QT clash). So, in a sense you are right in your essay when you say that we have both discrete and continuum: discrete is in the denumerability of systems; continuum is in the set of joint states of the systems.

        You are also very close to my vision when you say in your essay:

        "Therefore; the dance of information with form is best seen as a constant interplay where not only do the dancers interact with each other, but there is a continual exchange between dancers and the dance, where each is featured in turn. General information and open possibilities lead to actualities, then specific conditions engender new possibilities - and this cycle repeats - without end."

        This is the perennial cycle of the quantum cellular automaton, and the dancers are the quantum cells.

        Thank you for your rating and your wishes. I also rated well your essay.

        Best wishes to you

        Mauro

        David

        I thank you very much for your high opinion of my essay.

        I share your statistics about the contest. I share also many of your points in your essay (which I've not rated it, as you asked). What I do not agree with is your point:

        "Quantum entanglement opens the window for locally noncausal phenomena. We have to think wholly and incorporate global informational field - web of BITs - with links embedded in the quantum field."

        Causality is perfectly respected by entanglement. Indeed causality is the first of the six Pavia axioms (see my Ref. [3]). Nonlocal correlations are non causal, exactly in the sense that cannot be used to transmit information (Einsten's sense). They can be used to do teleportation and many other nice things, but not for communication.

        Thank you again,

        My best regards

        Mauro

        Beautiful professore :)

        thank you so much for answering my questions. I'm about to leave a reply above. Yes, I'd like to establish a new career as a writer with a goal to fascinate wide audiences -- and what can be more fascinating than novel ideas? To me, ideas themselves are more interesting than whoever claims their authorship. Very interesting ideas expressed in a lucid form reveal a beautiful mind behind them and that in turn leads to fascination with the person. But, as in it from bit, ideas always come first.

        Thank you again,

        -Marina

        Giacomo - I rated this yesterday but forgot to add a comment...

        I found your essay outstanding. I may not agree with the conclusion, but your description, logic and presentation were impeccable. The part I enjoyed most was your description of lattices in the quantum cellular automata.

        I wonder if you might find some synergy with the approach I have taken. I begin with the question of EPR, assume the constancy of speed of light, but question our ability to measure intervals in "time". I introduce the concept of a reversible subtime in order to overcome the Bell correlations, and show (at least in descriptive form) that it is possible to understand the results of these experiments without sacrificing locality.

        My conclusion: the photon is the carrier of time and the universe is a network automata.

        I will be honored to hear your thoughts after reading it.

        http://fqxi.org/data/forum-attachments/Borrill-TimeOne-V1.1a.pdf

        (sorry if the fqxi web site splits this url up, I haven't figured out a way to not make it do that).

        Lets connect when the contest is over.

        Kind regards, Paul

        paul at borrill dot com

          Dear Prof. D'Ariano,

          thank you for your detailed reply! I must say that your notion of energy is highly abstract and very difficult for a non-specialist to grasp. I wonder how this could be translated into the language everyone can understand. Could you give a more accessible version, as if in an interview for a general readership magazine?

          You wrote, "Being the imaginary logarithm of a unit-modulus eigenvalue, and being defined on the Brillouin zone, one still have some ambiguity in the interpretation as an energy..." -- no kidding! Your description gives me no core which I could dress with my imagination. I only managed to discern something akin to a vibration in "two opposite values (corresponding to particle/antiparticle), each with degeneracy two (corresponding to the spin degree of freedom)."

          Surely you have a crispier description of what is energy in your beautiful mind :)

          Sincerely,

          -Marina

          Beautiful Marina,

          I am very curious about your future books. I have a huge collection of books in physics, many of them nontechnical. Consider me available for feedback and editorial referee, if the ideas that you are considering are within physics. You just send an email to me. I've seen on Amazon you have two recent kindles with Dmitrii Suslin, unfortunately in Russian. I've also recently started a book-writing parallel life, and I will come out with a couple of books soon.

          Looking forward to reading your first book

          My best

          Mauro

          Paul,

          thank you for your compliments.

          I think that our points of view look similar, but instead they are quite different.

          I don't have atoms in interaction, and your networks have dynamical connections. Besides, the quantum cellular automaton is not just an idea, it is already a thorough theoretical framework. You should read my Ref. [7].

          Thank you again.

          My best regards

          Mauro

          Thank you for your reply. I have no technical papers on this, that is my next goal. What is meant by a quantum system is where we may differ, I see it as energy which can transfer information, and if I understand correctly you are saying a quantum is information that can transfer energy. Perhaps this is not significant but I suppose I am still trying to find something real to define a quantum system by.

          Carolyn

          Thank you :) I may take up your offer of a referee. As for Suslin's book on amazon, that's another MV, not me. It's a common name in Russia.

          All the best,

          -Marina

          PS I did not get your clearer reply to what is your notion of energy above. Pretty please?

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