curious.I'm not convinced they're an exact analogy but they might shed some light on things, so to speak.
(
Moon Girl Technologies horrendous beanbag,
Tue 8 Dec 2009, 21:34,
archived)
The analogy isn't at all exactI got the words the wrong way round, but it's the kinematics that are analogous. The dynamics are totally fucked. Meaning that the geodesics are the same (so Hawking's arguments are safe; they didn't rely on the Einstein equations) but the Einstein equations coupling them to matter are totally different. In relativity that's just the Einstein equations in their horrible non-linear glory. In acoustic holes it's pure non-relativistic wave equations -- you don't need to look at quantum fluids to get acoustic holes, you can build them in any perfect fluid. So the dynamics are governed by Newtonian mechanics.
Still, it is an interesting curiosity. There's a small but entertaining group of physicists trying to use these arguments to get a totally different picture on quantum gravity and the standard model by getting it from emergent systems in condensed matter. If you're actually interested, Volovik put up "The Universe in a Helium Droplet" on his website for free download a few years back; he basically found pretty mucha ll the symmetries of the standard model and of relativity emerging from perturbations in superfluid Helium II. The dynamics were totally wrong again, but the symmetries were all there. If someone can find a system where the symmetries *and* the dynamics emerge, then the conventional picture of finding unification by pushing to ever-higher energies and adding symmetry after symmetry will be overturned.
Which would be nice.
(Still, it is an interesting curiosity. There's a small but entertaining group of physicists trying to use these arguments to get a totally different picture on quantum gravity and the standard model by getting it from emergent systems in condensed matter. If you're actually interested, Volovik put up "The Universe in a Helium Droplet" on his website for free download a few years back; he basically found pretty mucha ll the symmetries of the standard model and of relativity emerging from perturbations in superfluid Helium II. The dynamics were totally wrong again, but the symmetries were all there. If someone can find a system where the symmetries *and* the dynamics emerge, then the conventional picture of finding unification by pushing to ever-higher energies and adding symmetry after symmetry will be overturned.
Which would be nice.
boris the spider,
Tue 8 Dec 2009, 21:47,
archived)
You know what,that is simultaneously both surprising and not surprising, somehow.
( Moon Girl Technologies horrendous beanbag,
Tue 8 Dec 2009, 21:53,
archived)