Spacetime weave - Bit as the connection between Its or the informational content of spacetime by Torsten Asselmeyer-Maluga

Dear Torsten,

I enjoyed your essay, although topology is not my strong suit. You speak of changes of state caused by an interaction in which it implies bit. I agree with this view.

You then analyze experiments in terms of closed curves in a manifold and ask whether the fundamental groups are isomorphic. You say there is no algorithm for a decision: "for two data sets of the space-time, there is no algorithm to compare the two sets. The result of an experiment is undecidable." In your Stern-Gerlach example, you point out that the knowledge of a measurement requires a coordinate system, and, if I understand you correctly, imply that the "set of space-time points therefore containing all information about coordinates, [and] in principle also all measurement results" imply that space-time is the bit.

I'm not sure how you envision "data sets". A primitive experiment can be based on counters generating numbers, and these numbers constitute the data. The question is what to do with the numbers, and how to 'model' reality with the set of numbers. I discuss the relevant algorithm for handling such data sets in my essay. I believe it might be relevant to your approach. I hope you find it interesting.

Although in reality the counter outputs tend to be correlated with the position of the counters in space-time, I believe this fact can be fully suppressed without changing the nature of the results. It's an interesting problem. I believe space-time can be abstracted away in favor of pure sets of numbers, although the result will be abstract 'features' that may only be meaningful when related to space-time.

Also interesting is that my model of the electron also leads to a torus, although I do not develop this in my essay. Perhaps all roads do lead to Rome.

There's another way in which our models seem to agree. You say "the choice of a global time produces a quantum state [...] but the choice of a local time structure gives a complicated partition of the space." I find the same result in my theory.

I like your alternative to the many worlds or branching space-time interpretation... although I suspect I am missing some of the fine points of your weave of saddle points.

I too focus on the fact that gravity couples to every kind of energy. You note this implies gravitation is energy exchange. I agree although I would perhaps see it as energy transformation. And the "formation" part of energy transformation is inherently coupled to the "formation" part of 'in'-formation, as I explain in my essay.

I will reread your essay for a better understanding.

Edwin Eugene Klingman

Dear Torsten,

very glad to see you enter this essay, I've been following your 'exotic smoothness'-approach for some time now (though I can't claim to ever have really sat down and worked through all the mathematical details). I'm also happy to see you dedicate your essay to Weizsäcker---I've already had a bit of a discussion with Phil Gibbs regarding his contributions, especially regarding its and bits (i.e. urs), and how they're somewhat sadly neglected these days. Looking forward to reading your essay, I'm sure I'll be back with further comments.

Dear Torsten,

Excellent essay! In my opinion, your program, as described in the essay, is very much in the spirit of Wheeler's dream "it from bit", and of Weizsacker's ideas. I have a lot of questions, but I think I will get answers to many of them from your papers. I hope to make more time to go carefully through all of them in a couple of months or so.

Good luck!

Cristi Stoica

P.S. I just saw you commented on my essay right now! Not, this is what I call entanglement!

Hi Torsten,

This is very nice to see you here. Excellent essay! In my 2011 FQXi essay I have used your publication (Torsten Asselmeyer-Maluga, Helge Rosé. On the geometrization of matter by exotic smoothness. arXiv:1006.2230v1) in references. That is very rare that academic entrant, as you, accepts physics as a manifestation of geometry. Even though barely all of physicists accept General Relativity they also accept a sudden jump from the big distance scale (GR) to the small one (QM) and the geometrization disappears. What about the distance scale invariance of the laws of physics? No one matters. It is explicitly showed in the ratings of essays.

In my essay in Table 1 I have defined that the conformally flat spacetime is the Bit and the matter is the It emerging from the spacetime but the reverse way is also possible. The matter and space have the same root (ancestor, predecessor). As you see we generally agree. Differences are in technical details.

In my opinion we need to find the one, universal, distance scale invariant metric, reducing to Einstein GR metric within Solar System distance scale and having ability to generate predictions. The first prediction of my (and also yours) concept is my spin experiment outcome. Then depending on the outcome we shall create the proper metric. The progress I have made since 2011 is that experiment.

Best regards

Hi,

Thanks for the message on my page. I will have time to read some essays this weekend, and yours is at the top of the list.

I wrote further on my blog page on exotic manifolds and its possible role in quantum gravity. You are right, as I remember, that there is a Godel-type result with result with respect to exotic R4s.

Cheers LC

Hi Torsten,

OK, I've had a little time to read now, so I can perhaps try to add my two cents. First of all, I think your realization that diffeomorphism invariance implies that a continuous manifold in GR doesn't contain more information than some triangulation is something that deserves being shouted from the rooftops---I've always thought that continua are something of an ontological burden, and should be avoided if possible. (The argument, or rather side remark, I make on this in my essay is essentially due to Achim Kempf---maybe you're familiar with his approach.)

I also was struck by the relationship you uncover between measurement and undecidability---this is another one of those ideas that keeps cropping up in unexpected places, and something I keep coming back to without, however, coming up with much of anything concrete (I've said a few things about this on the thread of Lawrence Crowell's essay). Perhaps the paper by Paterek et al., where they propose that outcomes of quantum experiments are random iff the proposition they encode is undecidable (from some set of axioms encoded in the preparation procedure), is of interest, but maybe it's a blind lead. Brukner has done some further work in this direction, and together with Zeilinger, has also professed views drawn very much from Weizsäcker.

Regarding Weizsäcker, yes, I think many of his cosmological arguments look somewhat quaint from a modern perspective, especially all the 'large numbers'-stuff, so I wouldn't want to commit myself to a 3-sphere cosmos as well. But I believe the argument for the 3-dimensionality of space being related to the 3-dimensionality of the qubit state space is not without merit; recently, it's been put into a modern information-theoretic form by Müller and Masanes. Of course, I suppose that to you, the advantage of 4-d spacetime is that it gives you a lot of smoothness structures to play with! (Incidentally, with your argumentation regarding 'the spacetime is the Bit', I'm not sure you're that far from the Weizsäckerian picture, in particular when you're talking about Stern-Gerlach measurements.)

Coming from the quantum side of things, I must confess that any attempt to 'geometrize the quantum' instead of quantizing geometry finds me a bit hesitant, but your argument regarding 'wild' embeddings as deformation-quantized versions of tame ones is nevertheless intriguing, I'll have to think about it for a bit. Maybe there's a sort of dual perspective thing here: you can start with the quantum, and get a 3(+1) dimensional spacetime out, or you start with the spacetime, and out pops the quantum (via a suitable embedding). That's probably a bit fanciful, but that way, everybody gets what they want...

Anyway, I've got to go now, it was a joy reading your essay, and I hope you do well in the contest!

Cheers,

Jochen

Mr.聽Asselmeyer-Maluga,

In your article you write "smooth spacetime contains only a discrete amount of information", are you refering for instance to quantum theory? In that case the gravitational wave is to be observed yet. If you mean every information, then please explain further.

Hi Torsten,

Your essay was excellent reading. I'm unfortunately not fluent in topology but have tried to explore similar ideas with a discrete background independent foundation. It's more like å gut feeling than anything else but I suspect that space-time is structure built with the bits, aka at least one level of complexity above raw bits. Is it room for that in your opinion?

I try to explore these Ideas in my completely non mathematical essay. And think that it should be possible to deduce why we have a velocity limit, and from there why there's no space-time beyond the event horizon in black holes (which is not covered in the essay) Thinking about bits as the foundation can give rise to ideas on how entanglement works, alternative interpretation of what happens in the double-slit experiment. Even how physical laws arises.

If you would take time to read it - and shoot it down if you like - I would be very happy because we have some similar ideas. (I would really like to get some feedback on some of the ideas there - trails of before the interesting ideas there. Probably because it's badly written)

Anyways - excellent essay and best regards

Kjetil

I read the first few pages of your essay with some care. It is interesting that you discuss the issue of quantum measurement. This touches on the issue of contextuality in QM. The Kochen-Specker theorem proves there is not context in QM for any quantum measurement. The observer is free to choose the orientation of their SG apparatus, which means choosing a basis in the Hilbert space of the system. Since any basis is freely given by any unitary transformation there is no QM prescription for a basis of choice. General relativity has a similar concept with covariance, and gauge theory is also similar. The measurement problem boils down to how it is that a quantum system is reduced to a certain eigenvalue, and in addition how it is that the basis for that eigenvalue is "chosen." In a Bohr or Copenhagen context this seems to suggest there are operating rules of nature outside of the QM, call it "classicality," that perform this role. In an MWI context there is still some auxiliary postulate or physical axiom involved with how it is the world eigen-branches into the many worlds.

This is not necessarily an act of consciousness. First off the splitting is perfectly random, and randomness may well have its fundamental meaning within quantum mechanics. The outcomes of measurements just updates a Bayesian prior on the nature of the world, and the information obtained is a measure of the Chaitan-Kolmogoroff entropy.

A measurement involves the use of energy. The Stern-Gerlach experiment imposes a divergent magnetic field in order to split the spin of electrons according to a certain z-orientation or basis. Energy is a funny thing, because its conjugate variable is time. There is no time operator that acts on a basis |t> so that T|t> = t|t>. The problem of course is that there would exist a unitary operator U = e^{-iεT} that continuously evolves the energy ε and energy spectra could not be discrete nor can it be bounded below. In a related manner with Fourier transforms we do not have negative frequencies, or negative energy, and integrate Fourier sums of ωfrom [0,∞) which differs from the position and momentum variables that are integrated from (-∞, ∞). Also position and momentum have classical correspondence with Poisson brackets in classical mechanics, while energy and time do not. Quantum measurements seem to require both time and energy. Energy must be applied to define a basis, and the succession of measurements, say of p and then x is done in a tensed fashion, and of course gives a different result than a measurement of x and then p.

I notice paper goes into the nature of time. The discussion appears similar to what you did last year. I will try to think about this, for time in general relativity is a really strange concept. The ADM approach to general relativity results only in the constraints NH = 0 and N_iH^i = 0. In a quantum setting with momentum metric variable π^{ij} = -iδ/δg_{ij} the Hamiltonian constraint results in the equation HΨ[g] = 0, which is related to the Schrodinger equation

HΨ[g] = -i∂Ψ[g]/∂t

But the time variation part is zero. In a general spacetime, say think of a spherical universe or an infinite open one with uniform distribution of mass-energy, there is no natural boundary from which one can integrate over a field to evaluate mass-energy inside; this would be a GR form of Gauss' law. I will have to ponder your ideas about time within this setting. If one is not able to define mass-energy, then correspondingly the definition of time is difficult as well.

Cheers LC

Hi Torsten,

I really appreciate that you took your time to read and comment. And I must apologize that my question was too hung up in my own ideas, and I really have to go deeper into your line of thought. (Which probably means that I have to learn and understand topology - now I wonder how I can squeeze that in an already tight schedule... :) )

A million thanks - on several levels

Kjetil