Geometry from Quantum Temporal Correlations
arxiv.org
arxiv.org
> 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.
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.
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.
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.
ianap
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)
"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)
Decoding quantum reality - with Vlatko Vedral @ The Royal Institution (4-Mar-2025; 59:26)
(I mostly watch while reading the running transcript these days - https://www.appblit.com/scribe?v=70FhS6NAbuA)
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.
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.
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...
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.
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.