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Octononionic gravitation?

  1. Feb 15, 2015 #1
    The existence of the graviton is repeatedly questioned and surrounded with deep doubts. This affirmation is supported by several elements:

    • The demonstration itself; one get the presumption of that existence via a simplification of the équations of the (generalized) theory of relativity (A. Einstein).

    • Numerous experimental unsuccessful attempts devoted to the detection of flows of gravitational waves proving the existence of quanta of gravitation; and the reader may find very interesting documents here on the PF explaining why it is difficult to discover these quanta.

    • Repetitive questions and answers formulated on PF.


      My two questions:

      1°) “To the repetitive question: “Why can we not detect gravitons?” can we propose the following answer: “They don’t exist!”?”


      2°) In the same vein: “What do you think about the actual research which could be called “the octonionic path” proposing a link between quarks, gluons and gravity at Planck scale?”


      For my self-defense I must say that I am not a professional teacher in physics but just an amateur with a passion for physics. My own approach is pushing me into the direction evocated in my second question and I am happy to state that my intuition seems to be in harmony with some professional essays. Following the rule here, I may propose the references (ignoring if it has been published and confirmed):


      F. D. (Tony) Smith Jr.: Calculation of 130 GeV mass for t-quark: arXiv: hep-ph/9301210v3 15 January 1993.

      C. White: New insights into soft gluons and gravitons, ICHEP 2012; University of Glasgow.

      R.S. Isermann: Of gluons and gravitons: exploring color-kinematics duality (Doctor Thesis, Germany 2013).

     
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  3. Feb 15, 2015 #2

    mfb

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    No. For example, until 1990, no planets around other stars were found - but the conclusion that they do not exist would have been completely wrong (now we know about 1900 of those exoplanets). The experiments were just not sensitive enough to detect them.
    The same is true for gravitons: most approaches of quantum theories of gravity predict them, but the same theories also predict that we cannot see them with current experiments. There could be heavier versions of gravitons and experiments look for them, but they do not have to exist or they could be out of range of current experiments.

    Gravitational waves are different, and there are multiple indirect observations of them. A direct observation should follow within the next years, if the experiments reach their predicted sensitivity.

    It is a mathematical analogy, not a physical one.
     
  4. Feb 15, 2015 #3
    Thanks.

    Concerning the second question:

    What do you exactly mean with this? Are you referring to the diverse cross sections calculations? Do you mean a new technic of calculation (example given: the “amplituhedron” cited on other pages on PF) is just proving that the superposition of, say, two gluons is mimicking the mathematical behavior of a graviton? Consequently: is inducing the idea of a similarity “two gluons = one graviton” and suggesting the non-existence of the graviton as “elementary quantum of gravitation”? Instead of that: suggesting that, at that scale, the gravitation is nothing else but a strong interaction between quarks?

    So my new questions:

    3°) what would be sufficient to prove that that mathematical similitude has a physical origin? (If these calculations are not sufficient);

    4°) if the graviton doesn’t exist per se but is fundamentally a superposition of two energetic states what is quantized at this scale (intra-nuclear)? The energy of course; but what else which would be the substitution for the non-existing quanta of gravitation? The area delimited by the positions of the quarks as predicted by the loop quantum gravity (LQG)?
     
  5. Feb 15, 2015 #4

    mfb

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    No. It is suggesting nothing.
    I can find the time an apple needs to fall down from a tree and the time a car needs to stop on a road with similar mathematical tools, that does not suggest an apple would have anything in common with a car, apart from being a moving object. And it certainly does not suggest cars grow on trees or apples would not exist.

    Mathematical tools never represent physical objects. Physical objects are represented in mathematics but the other direction does not work (see the car/apple example, based on the calculations alone you cannot tell which object was considered).

    Question 4 does not make sense at all.
     
  6. Feb 20, 2015 #5
    Thanks so much for the answers.

    The fourth question was perhaps not clearly exposed. I have recently discovered an old German book “Quarks (the stuff of our world)” dating from 1984 and explaining the story of the construction of the actual standard model. One of the central questions after the proposition of the existence of quarks (1964) was the one of the repartition of the electrical charge inside a proton. Experiments (SLAC) have proved that the inner charge of the nucleon was not homogeneously dispersed but concentrated in three sub-particles: the quarks.

    So I rephrase my fourth question. The theoretical part of LQG has predicted a quantization of areas (I think there are sufficient references exposed on PF). Quarks are confined inside of the nucleon. From which it could be inferred -with a mechanical viewpoint- that the three points permanently behaves as if they were moving inside a quasi-spherical envelop (like a triangle inside a sphere). Can we seriously go further on that way of thinking and imagine that the moving fictive triangular surface inside the nucleon is not anyone but in fact quantized as predicted by the LQG; that surface being constrained to have edges with dimensions depending on the energetic state of the nucleon (Depending on multiple influences; e. g.: any nucleon is surrounded with about one billions of photons as basic considerations arising from the cosmology teaches us)? With other words: “Does the predictions of the LQG apply at this scale?”

    Or is all this just a beautiful poetry arising from my imagination?


    I hope it was better formulated, even if it is wrong!
     
  7. Feb 20, 2015 #6

    mfb

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    Imagining quantum-mechanical objects as classical point-particles moving around rarely works. There is nothing triangular about/in a proton.
    Gravity has nothing to do with this, we can stay at normal quantum field theory (every unified theory has to have QFT as low-energy limit).
    What does "energetic state of the nucleon" mean? A nucleon has a fixed energy.
    That does not make sense.
    The low-energy limit, sure, but there nothing new appears.
     
  8. Feb 22, 2015 #7
    "...any nucleon is surrounded with about one billions of photons as basic considerations arising from the cosmology teaches us..." and "...What does "energetic state of the nucleon" mean? A nucleon has a fixed energy..."

    I got this information in reading another German book concerning the cosmology (Kosmologie; Die Wissenschaft vom Universum - E.R. Harrison). The question was about the number of photons in our universum and that was the given answer. If it is not correct or if doesn't apply here, I could have made a similar remark in involving the ocean of temporary particles and/or the influence of neutrinos passing through the region where the nucleon lives. I just was trying to say that the environment of a nucleon may have influence on its energetic level exactly as the impact of photons on an atom has an influence on the energetic level of the surrounding electrons (It was a kind of comparison; certainly a bad one, but it's difficult to phrase these phenomenon).

    "...Imagining quantum-mechanical objects as classical point-particles moving around rarely works. There is nothing triangular about/in a proton..."
    I agree with the first sentence - not with the second one... SU(3), 3 colores, 3 flavors... But it doen't matter.

    Thanks again for your patience.
     
  9. Feb 22, 2015 #8

    mfb

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    I guess this is the ratio of the number of nucleons to the number of photons in the observable universe. This does not mean there would be some correspondence. There are millions of ants for every human on earth, but you do not have to take care of ants if you want to understand a human.
    In a nucleus and in quark gluon plasmas, yes, otherwise not in any relevant way.
    This is as much a triangle as writing 3 posts.
     
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