5 ms·

Geometry from Quantum Temporal Correlations

60 points by ljosifov 1y ago

tomrod 1y ago
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 1y ago
  semanticscholar does this!
- dist-epoch 1y ago
  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.
  - tomrod 1y ago
    Yep. That's why I said I would love it as a browser extension.
- tough 1y ago
  emergentmind is a great llm wrapper / search for scholar articles
nyeah 1y ago
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 1y ago
  > 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/S1355219808000269 https://www.sciencedirect.com/science/article/abs/pii/S13552...
- naasking 1y ago
  Hossenfelder actually did a video on this just yesterday: https://www.youtube.com/watch?v=7See8OhtN-k https://www.youtube.com/watch?v=7See8OhtN-k
  - deleted 1y ago
    [deleted]
- dawnofdusk 1y ago
  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.
  - nyeah 1y ago
    Only I feel like it says Euclidean 3-space in the abstract.
patcon 1y ago
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=Geometry+from+quantum+temporal+correlations&btnG= 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 https://www.youtube.com/watch?v=7See8OhtN-k (h/t user naasking below)
- deleted 1y ago
  [deleted]
- gsf_emergency_2 1y ago
  From a skim, I'd summarize the paper thus: "product of (exponentiated) Paulis can be shown to have 2 eigenvalues" (& Let anyone who disagrees try to argue that quaternions aren't the best way to think about classical rotation)
stared 1y ago
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 1y ago
  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-doomed https://www.cornell.edu/video/nima-arkani-hamed-spacetime-is...
- sigmoid10 1y ago
  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 1y ago
    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.
ljosifov 1y ago
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 https://youtu.be/70FhS6NAbuA (I mostly watch while reading the running transcript these days - https://www.appblit.com/scribe?v=70FhS6NAbuA https://www.appblit.com/scribe?v=70FhS6NAbuA)
- neom 1y ago
  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 https://www.youtube.com/@TheRoyalInstitution/playlists - Also recommend World Science Festival: https://www.youtube.com/@WorldScienceFestival/playlists https://www.youtube.com/@WorldScienceFestival/playlists
  - ljosifov 1y ago
    excellent playlists - thanks!
neom 1y ago
There was a long paper on HN recently that I've been stuck thinking about. https://news.ycombinator.com/item?id=43990843 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.
magicalhippo 1y ago
I just watched a brief talk[1] over at Pirsa about the emergence of Lorentzian signature and time dimension from quantum fluctuations. As I understood it, starting with a uniform 4D metric, and then introducing a certain amount of asymmetrical "noise" to the background field through particle coupling, one of the dimensions got an effective sign flip in the metric leading to spacetime metric signature we know and love. Just a layman so can't comment on the details, but sounded interesting. [1]: https://doi.org/10.48660/25060082 https://doi.org/10.48660/25060082

60 points by ljosifov 1y ago

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 1y ago
semanticscholar does this!
dist-epoch 1y ago
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.
- tomrod 1y ago
  Yep. That's why I said I would love it as a browser extension.
tough 1y ago
emergentmind is a great llm wrapper / search for scholar articles

nyeah 1y ago

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 1y ago
> 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/S1355219808000269 https://www.sciencedirect.com/science/article/abs/pii/S13552...
naasking 1y ago
Hossenfelder actually did a video on this just yesterday: https://www.youtube.com/watch?v=7See8OhtN-k https://www.youtube.com/watch?v=7See8OhtN-k
- deleted 1y ago
  [deleted]
dawnofdusk 1y ago
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.
- nyeah 1y ago
  Only I feel like it says Euclidean 3-space in the abstract.

patcon 1y ago

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=Geometry+from+quantum+temporal+correlations&btnG= 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 https://www.youtube.com/watch?v=7See8OhtN-k (h/t user naasking below)

deleted 1y ago
[deleted]
gsf_emergency_2 1y ago
From a skim, I'd summarize the paper thus: "product of (exponentiated) Paulis can be shown to have 2 eigenvalues" (& Let anyone who disagrees try to argue that quaternions aren't the best way to think about classical rotation)

stared 1y ago

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 1y ago
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-doomed https://www.cornell.edu/video/nima-arkani-hamed-spacetime-is...
sigmoid10 1y ago
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 1y ago
  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.

ljosifov 1y ago

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 https://youtu.be/70FhS6NAbuA (I mostly watch while reading the running transcript these days - https://www.appblit.com/scribe?v=70FhS6NAbuA https://www.appblit.com/scribe?v=70FhS6NAbuA)

neom 1y ago
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 https://www.youtube.com/@TheRoyalInstitution/playlists - Also recommend World Science Festival: https://www.youtube.com/@WorldScienceFestival/playlists https://www.youtube.com/@WorldScienceFestival/playlists
- ljosifov 1y ago
  excellent playlists - thanks!

neom 1y ago

There was a long paper on HN recently that I've been stuck thinking about. https://news.ycombinator.com/item?id=43990843 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.

magicalhippo 1y ago

I just watched a brief talk[1] over at Pirsa about the emergence of Lorentzian signature and time dimension from quantum fluctuations. As I understood it, starting with a uniform 4D metric, and then introducing a certain amount of asymmetrical "noise" to the background field through particle coupling, one of the dimensions got an effective sign flip in the metric leading to spacetime metric signature we know and love. Just a layman so can't comment on the details, but sounded interesting. [1]: https://doi.org/10.48660/25060082 https://doi.org/10.48660/25060082