It from Qubit by Giacomo Mauro D\'Ariano

Dear Carlo

indeed, I don't rely on any background. The starting point is only relational, and that's where the finitely presented infinite group comes from. The quasi-isometric embedding in R^d is a temporary restriction in seeking all possible automata. On the other hand, I conjecture that there will be no automaton e.g. in hyperbolic spaces. In any case, the relations come first, and the embedding is a property of the group, and space and SR emergence come later.

The way I expect to get gravity is through a holographic principle from the automaton in an Euclidean space, a la Jacobson-Verlinde, and in such way curved space will be emergent, as a way to describe gravity phenomenologically, as Einstein did.

Dear Kevin

thank you very much for reading my essay and for your compliments.

You are surprised by similarities between our approaches, but indeed there is almost none. The approaches looked similar at the very beginning, more than three years ago, but now we are on another planet. Just few comments. My definition of information, and in particular, of "quantum information", has a precise technical connotation, which is given by the Pavia axiomatics of Quantum Theory. For me an electron is a theoretical notion, not an operational one (see my response to Matthew Leifer). Your work with Philippe is more concerned with the "mechanics", I am interested in the "quantum theory of systems", which can be applied e.g. to quantum fields, my main concern. My relations between systems are homogeneous, and that's why we get a lattice group. Homogeneity corresponds to universality of the physical law, as it is the case for the Maxwell field and the Dirac field. Dislocations would correspond to a random microscopical law, and you need to really recover all symmetries as emergent from randomness: but you need principles for why a kind of randomness or another! The automaton of Bialnycki-Birula is of the same kind of ours. However, what is relevant here is not the reverse engineering of the automaton, but the direct engineering: we start from few simple principles (QT, unitariety, locality, homogeneity, and isotropy) and derive two (not one!) Dirac automata that are connected by CPT, and that have Dirac as emergent in the relativistic limit (not in the continuum limit!) with Lorentz covariance becoming Smolin-Maguejo/Camelia's corresponding to breaking of CPT. We are not mimicking a theory: we derive theory from first principles.

As I said, at the beginning I was also surprised about the apparent similarity between your arxiv:1005.4172 and my early ideas on foliations arXiv:1001.1088 that later became the work with Tosini "Emergence of space-time from topologically homogeneous causal networks" on SHPMP http://dx.doi.org/10.1016/j.bbr.2011.03.031

However, SR and space-time come out when you seek the construction of the full reference frame a la Einstein. The precision of the reference frame depends on the precision of the clock. Are you willing to use a random clock? I think that one doesn't go far sticking on a classical network: the quantum nature of information is crucial to recover all continuous symmetries from the discrete ones (see my 2012 essay), since continuous symmetries (including Lorentz) are recovered from superposition between paths.

So, at this point, I think that the only common point between our approach is causality: the first of the six Pavia axioms.

We are studying a thoroughbred horse, not a flower.

My best regards

Mauro

Dear Sreenath

thank you very much for your very nice compliments.

In my essay, I dismounted the "It" with the main motivation of getting more attention to new alternative theoretical frameworks that I consider much more powerful. More than being interested in proving the Bit or the It what matters to me is finding the most efficient way of deriving the largest phenomenological scenario from the minimal set of principles, and I just showed how powerful the Qbit is! Unfortunately, I cannot say the same for the "It" of Tejinder Singh. Bohm's has now more than 60 years, and, honestly, even though it is always suggestive, we didn't get much from it. Singh doesn't even have a unique notion of "It". Is it "the particle"? What is a particle? The hyper-realists Singh and Bassi are trying to save a "mechanical" world, making it look even stranger and weirder than the quantum one. In support of their realism they are even invoking the trace-dynamics by Stephen L. Adler. Why? To rely on authority? A year ago I was curious, and bought the book of Adler (I got it used for a small price), and honestly I found his theory laking any kind of beauty. I later discovered that almost nobody knows it.

We should seek new physics, based on solid principles, principles based on logical arguments, not on the satisfaction of our imagination. At least, we should give to new physics more opportunities to express their potentialities, which had not been expressed up to now by the realistic approaches.

Thank you again

Mauro

Dear Than

thank you for your reading and compliments. I had a look ar your essay, and I should say that I do not share many of your assertions and generally the methodology. I do appreciate your interest in physics. Unfortunately, physics is a quite hard job.

My best regards

Mauro

Jim,

your essay has an attractive narrative, is pleasant to read and well written.

Regarding my personal opinions on the subjects, I just like to stress that the "It from Bit" that I like of Wheeler is not the act of creation of the universe. Likewise, I'm not very fond of the Antropic principle either.

But you master to put all subjects in a quite equilibrate way.

My best regards

Mauro

Domenico,

Can you just send me the interesting link?I cannot find it in that page.

Best

Mauro

Dear Chidi

I don't see what the Zeno "scenario" has to do with infinite regress.

Personally I cannot follow your arguments, since you are not following what I think is the correct methodology in theoretical research. I can considered arguments that run as a mathematical proof, made with a chain of logical implications, where every assertion is circumstantiated by facts or statements that everybody shares.

I therefore will not "do my best to prove you wrong", as you ask me.

If you need somebody proving you wrong, then you should submit a paper to a scientific journal. It my happen that an anonymous referee will do the job.

My regards

Mauro

Dear Roger

if I understand your position, you want to figure out how can make sense the notion of "space" in the presence of just few events. The answer is: it will make no sense. Think about: what is space for you? You can move in space, you can rotate something, you can walk, look at a distance ... the whole scenario makes sense only in the presence of infinitely many events, or, what we simply call "objects" that are macroscopical and made of a huge number of tiny parts, atoms, molecules, ... Whatever is "extension" needs parts, and not just a few of them.

Therefore, to figure out what does it mean to live with few "entities" and without space, try to imagine that you are an amoeba or any single-cell organism, that has no sight, no hearing, no other sense but e.g. three different kinds of different inputs--call them "a", "b", "c"--that are binary (on/off). Suppose also that the amoeba has brain that is a small subroutine, which is able to discover relations and causal connections. Such a mini-brain would figure out a space which would look similar to a finite group.

For a space like ours, we need to figure out infinitely many potential relations, corresponding to an infinite group. Such a group will be, however, finitely generated, by few simple relations, a bunch of translations, whose number of independent ones will define the space dimension.

Have fun

Mauro

Hi Yutaka,

nice to hear from you.

Yes, I'm implicitly assuming the dimension in the quasi-isometric embedding in R^3. My purpose is not to understand why 3+1. Let me add here that no theory ever, even remotely, had seriously addressed such an issue.

What we may have in the future (in the evolution of this theory) is discovering new unexpected physical features that are connected to the space dimension.

My best

mauru

Dear Mr Alessiani

you wrote your essay in form of a poem. You regard the bit as a metastable object. For me this is an irrelevant feature, since the bit, as a "system", doesn't carry its own dynamics. The dynamics is determined by the interaction.

My best

mauro