Relative information at the foundation of physics by Carlo Rovelli

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

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

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

Dear Carlo,

Re your answer (28th July) to my post: doesn't your determinism mean that all future physical outcomes are already fixed and "set in stone"? (Obviously I'm not referring to the issue of complexity, which means that future physical outcomes in real life usually cant be predicted).

Cheers,

Lorraine

Dear Carlo,

Re your answer (28th July) to my post: doesn't your determinism mean that all future physical outcomes are already fixed and "set in stone"? (Obviously I'm not referring to the issue of complexity, which means that future physical outcomes in real life usually cant be predicted).

Cheers,

Lorraine Ford

Dear Prof Rovelli,

very interesting essay. I completely agree with you about the role of information in physics. It is the relation between the objects which counts.

Your two principles (leading to quantum mechanics) are not totally new. von Weizsäcker also discussed the abstract derivation of quantum mechanics from finite Hilbert spaces (like C^2). I discuss it partly in my essay.

Maybe one point of disagreement: In my opinion, the relation between the discrete structure of spacetime (like the area quantization of LQG) and the smooth spacetime is not well enough understand. Is it really necessary, that the spacetime itself is discrete? Using diffeomorphism invariance, the information contained in a smooth 4-manifold is discrete (as I explained in my essay). Also the substructures like surfaces are partly regid (see for instance a incompressible surface in a 3-manifold which can be a topological expression for area quantization). Do not misunderstand me, I'm not an oponent of the discrete spacetime but the relation between discrete and smooth is not really explored (in dimension 4 or lower any triangulation (or PL structure) is uniquely determed by a smooth structure and back).

Maybe you have time to look in my essay.

Best wishes

Torsten

Carlos,

Interesting. Can you explain what a 'virtual photon' is, or why Snell's Law fails at Maxwell's near'Far field transformation along with Fresnel's refraction? We have to call the unexplained non-linear effect 'Fraunhofer' radiation and slip it under the carpet to be rationalised later! Unless you can offer an explanation?

Do you not believe that understanding the underlying quantum mechanism to the transform will aid our comprehension, so remove the anomalies and paradoxes (including such as Kinetic Reverse Refraction, another well known effect from optical science with not consistent theoretical explanation).

A mathematical identity is of course not a true or even absolutely precise 'explanation' of natures uncertainties, just a good approximation, Yes?

So I am suggesting perhaps these are the things we DON'T yet fully understand, or do you truly believe we do?

Peter

Dear Carlo,

Thank you for a most illuminating essay, which deserves top marks.

You explained how "selected structures define finality". There is clearly a Lagrangian cast to this statement if the action is bound globally and is time symmetric. It appears that the relative information gained by one system (i.e., an observer) about another system (i.e., a quantum state) is reflexive. In other words, the act of measurement defines both systems. The observer erases the entanglement information which encodes the global interconnectedness of herself and the other system. Both she, as perceiver, and the measured state, as the perception, emerge as ontic entities. (See my essay "A Complex Conjugate Bit and It".)

This "infinite game of mirrors reflecting one another" brings to mind the image of Indra's net, with a jewel glittering at every node.

Best wishes,

Richard

Dear Professor Rovelli,

While you tell an enjoyable tale and make a good point; I found your essay a bit disappointing, playing as it does upon the common misconceptions about entropy, and the confusion that exists about the extent to which the different types of entropy are interchangeable. Of course; the Scientific American editors did it too, when they ran an article about non-linear entropy in the mesoscale regime by J. Miguel Rubi, by proclaiming on their cover that his studies show how nature breaks the 2nd law of thermodynamics. However; if you read Rubi's version, he carefully explains that thermodynamic entropy steadily increases while the system displays alternating regimes of chaotic and orderly forms - in apparent defiance of the 2nd law. Or at least that defiance is what appears true for those who equate entropy with disorder.

Personally; I prefer the spreading metaphor championed by Leff, for thermodynamic and mixing entropy. It seems that due to efforts by Lambert and others, the 'entropy is disorder' description is almost completely absent from Chemistry textbooks, as it brought confusion and was distracting from the thermodynamic aspects of Chemistry, but in Physics this idea of energy dispersal being associated with thermodynamic entropy was kind of skipped over as statistical models based on information entropy were broadly adopted or already in use. Still; it is arguable that the specific meaning defined by Clausius was already changed somewhat by Boltzmann, when he suggested that disorder's increase was associated with growing entropy, and that not all entropy is the same.

Also; I think it is often glossed over that there is a specific n involved, the number of molecules in molar volumes of gases, which has the effect to make the system under study quantum mechanical. When there is a discussion of microstates, it is in terms of equivalent microscopic state changes which are all equally possible because they yield the same macroscopic condition. It is as though nature is performing one mother of a path integral, while we are just reading the temperature and pressure on a gauge. I think nature's way of defining things is indeed through relative information, and you have done a wonderful job of conveying this. A constrained system could consist of cranks and pistons, but it could be a pair of entangled particles where one has been partially measured as well. So your essay was enjoyed, and it made me think; but confusion about entropy is a bugbear for me, and I think your conclusion stands just as well without confusing the issues.

All the Best,

Jonathan