[HN Gopher] Geometry from Quantum Temporal Correlations
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       Geometry from Quantum Temporal Correlations
        
       Author : ljosifov
       Score  : 42 points
       Date   : 2025-06-13 13:21 UTC (9 hours ago)
        
 (HTM) web link (arxiv.org)
 (TXT) w3m dump (arxiv.org)
        
       | tomrod wrote:
       | My understanding is limited, but this seems pretty interesting.
       | I'm not quite sure I follow the argument that space is a
       | correlated interaction at the quantum level.
       | 
       | As a total tangent: it would be interesting to have an LLM-based
       | modality, like a browser extension, where a user could highlight
       | academic concepts in a pdf and drill down. Academic writing, by
       | convention and necessity, is terse and references prior
       | literature, sometimes opaquely. So getting up to speed in the
       | literature takes significant effort.
        
         | yababa_y wrote:
         | semanticscholar does this!
        
         | dist-epoch wrote:
         | You can do it with todays LLMs. First describe your level (how
         | much math, etc you know) then ask it to explain a concept. Then
         | ask further questions.
        
         | tough wrote:
         | emergentmind is a great llm wrapper / search for scholar
         | articles
        
       | nyeah wrote:
       | Any physicist willing to comment? Sure, the spin matrices were
       | built to deal with three spatial axes. Is there more to the paper
       | than that?
        
         | n4r9 wrote:
         | > the spin matrices were built to deal with three spatial axes
         | 
         | If I understand correctly, it kinda happened the other way
         | around. First the Pauli matrices were introduced to explain
         | unexpected degrees of freedom in experimental observations;
         | then the term "spin" was proposed because the operators related
         | to each other in the same way as classical angular momentum
         | operators. See e.g.
         | https://www.sciencedirect.com/science/article/abs/pii/S13552...
        
         | naasking wrote:
         | Hossenfelder actually did a video on this just yesterday:
         | 
         | https://www.youtube.com/watch?v=7See8OhtN-k
        
         | dawnofdusk wrote:
         | Not in this field directly, but first of all, talking about the
         | "geometry of space" is more than just saying there are three
         | spatial dimensions: geometry involves the local curvature of
         | the object. Historically the Pauli matrices are discovered by
         | assuming certain symmetries of spacetime. This paper shows the
         | other direction also makes sense: if we assume certain
         | structure on quantum observables, measurable only by temporal
         | measurements and _independent_ of the content of the quantum
         | state (i.e., a measurement of any system will do), we can get
         | the spatial symmetries we want.
         | 
         | I suppose the ideal outcome is that there is some sort of
         | exotic algebra of observables which is well motivated somehow
         | by purely quantum considerations and by serendipity induces all
         | the usual spacetime symmetries + extra stuff we didn't know
         | about. This paper itself is cute but not sure if it's very
         | impactful, I would defer to domain experts.
        
       | patcon wrote:
       | Can't assess content beyond amateur attempt, but am curious.
       | 
       | Second author seems very established, so some social proof there:
       | https://scholar.google.com/scholar?hl=en&as_sdt=0%2C5&q=Geom...
       | 
       | EDIT: yesterday's video on the paper by Sabine Hossenfelder:
       | https://www.youtube.com/watch?v=7See8OhtN-k (h/t user naasking
       | below)
        
       | stared wrote:
       | Well, it feels shaky. First, it starts with:
       | 
       | > There is a growing consensus in theoretical physics that
       | spacetime is not a primitive notion
       | 
       | That's a very strong statement. I'm not sure what the actual
       | distribution of views on spacetime is, but there certainly isn't
       | a _consensus_ on that matter. If I wanted to establish
       | credibility, I wouldn't open a paper with such a dubious claim.
       | 
       | Second, Pauli matrices are highly relevant to space (see: Dirac
       | spinors; but also, they can be used for quaternions--i.e.,
       | rotations in 3D). Using Pauli matrices to argue that we live in a
       | 1+3 spacetime feels, at the very least, like a circular argument.
        
         | bofadeez wrote:
         | No this has been a talking point by top spacetime theorists for
         | a very long time. E.g. https://www.cornell.edu/video/nima-
         | arkani-hamed-spacetime-is...
        
         | sigmoid10 wrote:
         | The idea that spacetime is emergent and not fundamental dates
         | back to the 60s and has seen some pretty neat stuff along the
         | way, like Bekenstein and Hawking discussing information
         | problems in the 70s that hinted at a deep connection between
         | gravity and thermodynamics. Then in the 90s we had Jacobson
         | deriving General Relativity from the first law of
         | thermodynamics and in the 2000s we had Verlinde combining this
         | with holography. It's not a "solved" problem by any stretch,
         | but some of the greatest physicists of their generation have
         | meddled with this and I think there are almost none left who
         | would refute the basic idea. It's the details that people are
         | still arguing about - which now include this paper.
        
           | stared wrote:
           | There are quite a few ideas! Myself, I would bet on
           | Polymarket that there is something more fundamental than
           | curved 1+3 spacetime.
           | 
           | Some are, as you said, in thermodynamics. In the String
           | Theory, 1+3 is a somewhat reduced space from original 26
           | dimensions or so. (This "somewhat" is the core issue.)
           | 
           | So sure, "The idea that spacetime is emergent and not
           | fundamental dates back to the 60s" would work as an awesome
           | opening of the paper.
        
             | sigmoid10 wrote:
             | The "growing consensus" bit literally alludes to all these
             | developments. But granted, you have to be versed in the
             | field to understand this. On the other hand, this is a
             | research paper. It is not written for laypeople.
        
         | abdullahkhalids wrote:
         | "Growing consensus" is not the same thing as consensus. If
         | currently 20% of the top physicists think spacetime is not a
         | primitive notion and this number has monotonically increased by
         | 1% every year for the past decade, that would be an example of
         | "growing consensus".
         | 
         | Besides, Vlatko Vedral is a top theorist in the area, who talks
         | other top theorists at conferences and workshops. He wouldn't
         | say this if he didn't think other top theorists didn't agree
         | with him.
        
           | stared wrote:
           | Weasel words (or other common sense statements said passed as
           | objective truths) should not be a part a scientific paper,
           | regardless of who is writing that (yes, I know that Vlatko
           | Vedral is an established researcher).
           | 
           | Myself, I am quantum physicist by training. While I have
           | certain views on stuff (e.g. many-world interpretation and
           | decoherence, in the line of ZH Zurek), I actually cite
           | surveys on the view on physicist on QM interpretation. (Even
           | though I "know" from my personal observations that all almost
           | all theoretical physicists are in the MWI.)
           | 
           | > If currently 20% of the top physicists think spacetime is
           | not a primitive notion and this number has monotonically
           | increased by 1% every year for the past decade, that would be
           | an example of "growing consensus".
           | 
           | Awesome! Then any reference with such data would be useful.
           | If one cannot make (or even create a personal survey), then
           | one should not write such things as facts.
        
         | nh23423fefe wrote:
         | I don't think the Pauli matrices are used per se I think they
         | are derived from the anti-commutation criteria of the basis
         | elements. I don't know what justifies that criteria though.
         | 
         | ianap
        
       | ljosifov wrote:
       | A recent Vedral (one of the authors) talk -
       | 
       | Decoding quantum reality - with Vlatko Vedral @ The Royal
       | Institution (4-Mar-2025; 59:26)
       | 
       | https://youtu.be/70FhS6NAbuA
       | 
       | (I mostly watch while reading the running transcript these days -
       | https://www.appblit.com/scribe?v=70FhS6NAbuA)
        
         | neom wrote:
         | As a side note, The Royal Institution is one of the best
         | youtube channels around, cannot recommend it enough, they do a
         | great job with their playlists:
         | https://www.youtube.com/@TheRoyalInstitution/playlists - Also
         | recommend World Science Festival:
         | https://www.youtube.com/@WorldScienceFestival/playlists
        
       | neom wrote:
       | There was a long paper on HN recently that I've been stuck
       | thinking about.
       | 
       | https://news.ycombinator.com/item?id=43990843
       | 
       | Jaeger et al.'s ideas on consciousness is in which many "baked
       | in" structures are emergent, and that living or "cognitive
       | systems" similarly generate meaning from underlying complexity
       | without being reducible to a straightforward set of rules. Macro
       | level "givens" (geometry) can arise from deep nonclassical
       | processes. "procedurally generated quantum reality" or something.
        
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