5 ms·
>it exists outside of spacetime So I guess this theory won't be subject to empirical testing any time soon?
by optimalsolver 2y ago
>it exists outside of spacetime
So I guess this theory won't be subject to empirical testing any time soon?
- jungturk 2y agoPerhaps "outside" means "resident on the boundary of", a la holograms and Maldecena's AdS/CFT work, and so still within reach of experiment?
- codethief 2y agoHow is AdS/CFT (as it pertains to describing spacetime & the Standard Model) within reach of experiment? We're not even in an AdS universe.
- hughesjj 2y agoI was going to write something up but honestly the top two answers in this physics stack exchange do it more competently and comprehensively than I'm able https://physics.stackexchange.com/questions/122540/why-are-anti-de-sitter-spaces-so-interesting-when-we-believe-the-universe-is-exp https://physics.stackexchange.com/questions/122540/why-are-a... My takeaway/summary is 'AdS/CFT let's you temporarily change your space/model to make the math easier and then map it back into the original model. Although we don't currently have such a model specified for our particular observed universe, it still allows us to study functionality equivalent behavior and make some determinations over what is/isn't/could be possible'
- codethief 2y agoFrom the link you posted: > Ok, so if I understand correctly, AdS spaces aren't meant to directly model the universe, but rather are used as a tool to make certain calculations in CFT easier? GP's comment was modelling the universe as AdS/CFT, though, which is why my question addressed precisely that part: > How is AdS/CFT (as it pertains to describing spacetime & the Standard Model)
- jungturk 2y agoSorry, my point was to (almost facetiously) interject the topological concept of "boundary/bulk" correspondence (as also exists with holograms & AdS/CFT) rather than suggesting the correctness of AdS/CFT. The idea that "outside" becomes available via a change in perspective from boundary to bulk.
- austinjp 2y agoFor those who, like me, are not familiar with AdS/CFT, it's "anti-de Sitter/conformal field theory correspondence" which is "a conjectured relationship between two kinds of physical theories", allowing quantum field theories to be made more mathematically tractable. https://en.m.wikipedia.org/wiki/AdS/CFT_correspondence https://en.m.wikipedia.org/wiki/AdS/CFT_correspondence
- downboots 2y agoA universe where everything can be empirically tested would be conveniently and suspiciously human-centered
- janto 2y agoAnd neccessary.
- hughesjj 2y agoWell, likely necessary to determine a unique and comprehensive, consistent model (or equivalence class thereof) There's no guarantee such a model can be determined via an observer in the universe the observer is observing. Functionality though, yeah that's the goal to either find such a model or show that one can't exist, or can't be proven one way or the other.
- naasking 2y agoI don't see how that follows. Almost nothing about what we've discovered is human-centric, we've had to build machines to sense beyond our human perceptual limits. In what ways are gravitational waves detected by LIGO human-centric?
- janto 2y agoIn that humans built LIGO to bring forth phenomena for them. There is no science without an observer. The universe might exist without us, but without an observer there is no-one to describe it.