Dear Carlo

I enjoyed your lucid essay. You make it clear that particles somehow exchange information, but you provide no 'mechanism' by which such information is transmitted - what would be the equivelant of Shannon's information channels, say at the Planck scale?

My Beautiful Universe Theory also found here suggests precisely how the presumed dielectric nodes making up a lattice of the Universe transmit angular momentum (one can call it information about angular momentum!):locally, causally and linearly, and without the need for any sort of observer.

With best wishes,

Vladimir

Dear Professor Rovelli

Richard Feynman in his Nobel Acceptance Speech (http://www.nobelprize.org/nobel_prizes/physics/laureates/1965/feynman-lecture.html)

said: "It always seems odd to me that the fundamental laws of physics, when discovered, can appear in so many different forms that are not apparently identical at first, but with a little mathematical fiddling you can show the relationship. And example of this is the Schrodinger equation and the Heisenberg formulation of quantum mechanics. I don't know why that is - it remains a mystery, but it was something I learned from experience. There is always another way to say the same thing that doesn't look at all like the way you said it before. I don't know what the reason for this is. I think it is somehow a representation of the simplicity of nature."

I too believe in the simplicity of nature, and I am glad that Richard Feynman, a Nobel-winning famous physicist, also believe in the same thing I do, but I had come to my belief long before I knew about that particular statement.

The belief that "Nature is simple" is however being expressed differently in my essay "Analogical Engine" linked to http://fqxi.org/community/forum/topic/1865 .

Specifically though, I said "Planck constant is the Mother of All Dualities" and I put it schematically as: wave-particle ~ quantum-classical ~ gene-protein ~ analogy- reasoning ~ linear-nonlinear ~ connected-notconnected ~ computable-notcomputable ~ mind-body ~ Bit-It ~ variation-selection ~ freedom-determinism ... and so on.

Taken two at a time, it can be read as "what quantum is to classical" is similar to (~) "what wave is to particle." You can choose any two from among the multitudes that can be found in our discourses.

I could have put Schrodinger wave ontology-Heisenberg particle ontology duality in the list had it comes to my mind!

Since "Nature is Analogical", we are free to probe nature in so many different ways. And you have touched some corners of it.

With great regards,

Than Tin

Dear Carlo,

Sorry to trouble you. I am not a professional physicist but I have a question I will like to be enlightened about. I am taking advantage of this forum to ask an expert so I can be clear although this may not be the subject of your essay. Is it being implied by the relational view of space and as suggested by Mach's principle that what decides whether a centrifugal force would act between two bodies in *constant relation*, would not be the bodies themselves, since they are at fixed distance to each other, nor the space in which they are located since it is a nothing, but by a distant sub-atomic particle light-years away in one of the fixed stars in whose reference frame the *constantly related* bodies are in circular motion?

You can reply me here or on my blog. And please pardon my naive view of physics.

Accept my best regards,

Akinbo

    Hey C. Rovelli,

    Neat short essay! I Like here that entropy and information is dealt with as a tool.

    Dear Prof. Rovelli,

    A good and thought provoking essay. If I understand correctly the idea is first the primacy/importance of the macro variables in determining entropy (that the entropy is a function primarily/only of these marco variables like volume, temperature, pressure) and second the importance of the interaction of two systems and the degrees of freedoms that come into play in these interactions. For example, certainly ignoring interactions or back reaction in black hole evaporation is a bad idea at the end stages where a BH evaporates. But as well this is a difficult problem.

    I did have one open ended question -- many times for quantum systems one discusses "entanglement entropy"/von Neumann entropy/fine grained entropy which is defined as -Tr (p log p) with p being the density matrix of the system (I'm am just looking in detail at this so do not have very good intuition which is why I use formulas instead of words). This entanglement entropy has some odd feature in certain situation -- for example unlike usual thermal entropy it is not additive. So my question is "What can one say about entanglement entropy in the context of your arguments?" A quantum entangled system is "interacting" (sort of) but I'm not sure in the sense you mean interaction. In any case I am just beginning to look into this type of entropy and it has some (to me) odd features and it seems your arguments may have something to say in this regards.

    Best,

    Doug

      Dear Carlo,

      « Relative information at the foundation of physics »

      This title is revealing that information is the basis of our reality.

      If reality is made both wave and particle.

      Why not « Quantum and Wave Mechanics » ?

      And where is the binary « 0 » and « 1 », in nature.

      Accordingly to eDuality, see my essay which is less scholarly.

      I rated your essay accordingly to my appreciation.

      Respectfully, and good luck.

      Please visit My essay.

        Sorry for absence.

        I was at various conferences (Oxford on Quantum and Cosmology, Nottingham on Relativistic Quantum Information, GR20 in Warsaw, and LOOPS13 in Canada).

        Now I am back, and I read agin the posts.

        Carlo

        Hi Dough.

        Von Neumann entropy is quintessential "relative" information, of the kind I am talking. It is not just "entropy of a system": it is entropy to a system relative to another. I am trying to work out the precise relation in these days.

        Best, Carlo

        Careful, "Relative information at the foundation of physics" does NOT imply that physics is nothing else than relative information. Foundations are often large and rich. Information is one of the ingredients for better understanding the world. I do not think (nor know) if it is the only one...c

        "In a recent article you have, in effect, pronounced that the future of our world is already fixed and set in stone. Game over. In the face of the likelihood of catastrophic climate change, your's is an uninspiring position."

        Oh no! If this is what you read in my article, I really have not been able to explain my ideas !!

        carlo

        No, I do not. Shannon has provided a very strait-forward and well defined way to understand the meaning of "the same information". c

        Carlo,

        please help me to understand: does ANYTHING change future outcomes? What DOES change future outcomes?

        (Obviously I'm not referring to the issue of complexity, which means that future outcomes in real life usually cant be predicted)

        Lorraine

        Thanks so much Carlo for replying. Your reply suggests then that what determines whether two constantly related bodies will experience centrifugal force is in their local environment? If so, since it cannot be the bodies themselves it must be in space even if you may want to call this a field.

        Following additional insights I have gained from interacting with FQXi community members, including your respected self (on Jun 26 and other days), perhaps you will like to view the judgement in the case of Atomistic Enterprises Inc. vs. Plato & Ors delivered on Jul. 28, 2013 @ 11:39 GMT. Thanks

        I wish I had full access to the Wheeler article I mentioned before. I understand he compared his elementary quantum phenomenon to monads.

        All the best, sir

        Akinbo

        Dear Carlo,

        I thank you for your excellent analysis making a fascinating essay. But I find an apparent contradiction I wish to resolve.

        The finiteness at the Planck length I can agree as wavelength gamma, then you seem to assume this is equivalent to the binary 0,1 of Shannon. But then you also find, (agreeably) that; "it is always possible to acquire new information about a system." Leaving the apparent dichotomy. As the signals we use as far from gamma, might it be that all that new information is coded in the 'noise' limiting the channel capacity?

        I very much liked your comment; "The interactions between spacetime regions are exchanges of informations across spacial regions. These are quantized and discrete. The quantum discreetness, united to the fact that the geometry of spacetime is dynamical, and therefore quantized, leads immediately to the discretization of space," Which I've considered in a more realist and mechanistic way for the last two years

        I hope you may be able to advise me on the veracity of my related proposal this year, of an underlying mechanism giving the the 'missing element' you identify, by decoding that 'noise as distributions 'between' cardinals, so 'curved' not linear, (and 3D+t not 2D+t waves). Still finite but filling a massive gap with that 'new information' which I suggest how we may "acquire".

        I love the Democritus quote, but suggest more. Do you know of any observable physical entities entirely identical? I propose A=A is fine for maths but that the = sign is metaphysical, so in reality we can't have Aristotle=Aristotle as there is only one real Aristotle. Are even stem cells really identical? And do particles really have zero complex structure as QM assumes?

        I hope you may also comment on my finding explaining of the anomalies in Alain Aspects data, offering an EPR resolution without FTL. fqxi; The Intelligent Bit.

        Very best wishes.

        Peter

          Dear Carlo,

          You have written an entertaining essay but I think that things could be greatly simplified if theoretical physicists would be a bit more adventurous with subversive ideas.

          For example, Hawking and Bekenstein showed that the entropy of a black hole is proportional to the area of its event horizon. t'Hooft and Susskind then came up with the Holographic principal but can't find a proper working scenario for it. The "divided by 4" in the BH entropy formula is giving us a clue.

          I believe that a black hole is in fact a plain circle and its entropy is proportional to the area of the circle (there goes the "divided by 4").

          Why don't you try to use your LQG in the context of successive 2D frames ?

          (each 2D frame representing the "present" information for an internal observer in the frame, each frame being a scaled up version of the previous one and the "present" information is moving through the frames at the speed of light).

          I have done this in my simple theory and I got some great results. I am only an amateur physicist, so I am sure that you would discover a lot more if you tried that approach.

          For example, I have discovered (and I can show) that the proton's diameter is just a scaled up version of the Planck Length and that the proton's mass is just a scaled down version of the Planck mass.

          By using this simple "holographic" principle and a simple scaling rule, I concluded that Dirac was correct when he came up with his Large Numbers Hypothesis, unfortunately not many current physicists want to even consider that he was right.

          I know that you like to question the fundamentals (that's why I am one of your fans), so, please be even more adventurous and at least consider some of my ideas even if I am a nobody.

          Best regards,

          Patrick

            • [deleted]

            Yes,

            http://intranet.catie.ac.cr/intranet/posgrado/Agrof-Cult-AyP/

            Curso%20SAF%20A%20y%20P%202011/Propedeutico%20Agroforestal/Lecturas%20optativas/The

            %20Measurement%20of%20Species%20Diversity.pdf

            Annual Reviews is cooperating with http://www.jstor.org

            Eckard

            The reason it is always possible to acquire new information is quantum mechanics. It is the same reason for which after you have measured the z-component of angular momentum you can still get new information by measuring its x-component. In doing so, the information about the z-component becomes irrelevant, therefore the new information is acquired without increasing the total amount of information available.

            This I think characterizes quantum theory. I do not think that we learn more by trying to connect this to some underlying quantum fluctuation. Like we did not learn more about the Maxwell equations by trying to guess some underlying mechanical explanation of these equations. We learnt more about them by realizing that they were simply describing some simple fact about nature, which we had discovered.

            c

            Hi Patrick.

            Nobody is "a nobody" in science. Remember the patent office clerk... I looked at your UB's and CBU's. Quite surprising indeed your numbers! Id didn't check out the arithmetic. Does it really give that? It should not have been easy to find these formulas... I'll try to see if there is something I can use... Best! carlo

            Hi Carlo,

            Thank you for your reply.

            Yes, the arithmetic is correct.

            No, it was fairly easy to find these formulas, it is all simple logic.

            Have you checked out the proton's diameter and the proton's mass formulas?

            If I am correct, wouldn't this give us a big clue about the current proton's radius measurement problem ?

            A

            Patrick