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New math proves that a special kind of space-time is unstable
- hpoe 6y agoSo my understanding is that the Maledecena conjecture that provide a correspondence between AntiDeSitter Space and CFT was a crucial breakthrough for proving string theory. Does this discovery make an impact on string theory?
- candiodari 6y agoDoes this mean we're now sure that spacetime has positive curvature ( >= 0 ) ?
- cft 6y agoAdS has constant negative curvature. I don't think he proved that any spacetime with a negative curvature is unstable. But experimental data so far show that the universe has zero curvature.
- shoes_for_thee 6y agoHey, are we emulsion floating on the surface tension of a still, multi-dimensional pond in which we all eventually sink? asking for a friend
- ChrisLomont 6y agoNot necessarily. These three models are the simplest ones - and our universe has a much different matter distribution than any of the three. It's still possible that adding more features to the solution, such as mass or angular momentum, changes the stability. It's also possible we do live in an inherently unstable universe, but even unstable things can have long periods of time elapse before breaking down. It's mostly an interesting mathematical curiousity.
- tzs 6y ago> If the boundary is, in fact, reflective, nothing can leak out of AdS space-time. So any matter or energy put into the system could potentially get concentrated — perhaps to such an extent that a black hole would form. So in space-time that does not have a reflective boundary, is the implication that matter or energy can leak out? Where does it go?
- frisco 6y agoIf my understanding is right, de Sitter space effectively has no boundary, in the same way that a sphere has no edge.
- pmiller2 6y agoHere is what I believe is the most relevant paper by Moschidis: https://arxiv.org/abs/1812.04268 https://arxiv.org/abs/1812.04268 I find it mildly amusing that this work is being done by mathematicians rather than theoretical physicists.
- state_less 6y agoDidn't Einstien use Minkowski's geometry for his key theories? Seems like it's helpful to have a few mathematicians involved in the project.
- javajosh 6y agoNot really my field, but I think Riemann had more of an impact on Einstein in that he was looking for a mathematical structure that fit his intuition about spacetime, and he dug up a 50-year old theory and applied it to GR. My understanding is that Einstein was searching for a long time for the right tool, and went down a lot of dead-end paths, before he discovered Riemann geometry.
- pmiller2 6y agoAs I recall my history, it was actually believed that Einstein's first wife, Mileva Marić Einstein, who provided at least some of the mathematical muscle needed for GR [0]. --- [0]: https://blogs.scientificamerican.com/guest-blog/the-forgotten-life-of-einsteins-first-wife/ https://blogs.scientificamerican.com/guest-blog/the-forgotte...
- qchris 6y agoI definitely agree he had a mathematician working with him to help, but am not sure it was his wife. I think that there's varying interpretations of her contributions to A. Einstein's work. If I'm remembering correctly, Walter Isaacson's Einstein biography tended towards says that she didn't truly contribute much to any of the work he did around that time, but that he did have a colleague or two formally trained in non-Euclidean geometries that he spent a lot of time working on GR with.
- empath75 6y agoCan someone expand on what this means for AdS/CFT?
- seemslegit 6y ago“If you perturb AdS space-time and wait a sufficient time,” Moschidis said, “you’ll end up with a different geometry — one that contains black holes — and it’s no longer AdS. That’s what we mean by unstable.” But our universe is known to contain black holes and yet isn't it being AdS considered an open question ? Or is it only an open question about the universe during its infancy ?
- frisco 6y agoOur universe is definitely not described by anti-de Sitter space. It might be de Sitter space though.
- seemslegit 6y agoThen why do we care so much about AdS/CFT correspondance ?
- ganzuul 6y agoWhat is special about wave 2? Wouldn't 3...n behave the same way and result in stability?
- nwallin 6y ago> The Stanford mathematician Jonathan Luk describes Moschidis’ work as “amazing. … What he’s discovered is a rather general instability mechanism” — one that could apply to other settings, unrelated to AdS, in which matter or energy is cooped up within a physical system that has no escape hatches. So the I'm not particularly interested in the specific result, but the "rather general instability mechanism" is potentially game changing. Does any know how general this mechanism is? Could it apply to Navier-Stokes?
- xwdv 6y agoCan anyone relate this to a human scale? What would it mean to be caught in an unstable space-time? How could it be exploited?
- pontifier 6y agoWhen they mentioned "other settings, unrelated to AdS, in which matter or energy is cooped up within a physical system that has no escape hatches." I thought immediately of the fusion reactor I've been working on. In my device, an arangement of static fields creates a region in which deuterium energised in a specific reflects back to the center forever and has no outlet even after non-fusion collisions. The "instability" in my system comes because the extreme stability in the oscillation should cause even a rare event (DD fusion) to happen eventually with 100% probability.