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Simulations Back Up Theory That Universe Is a Hologram
ananyo writes "A team of physicists has provided some of the clearest evidence yet that our Universe could be just one big projection. In 1997, theoretical physicist Juan Maldacena proposed that an audacious model of the Universe in which gravity arises from infinitesimally thin, vibrating strings could be reinterpreted in terms of well-established physics. The mathematically intricate world of strings, which exist in nine dimensions of space plus one of time, would be merely a hologram: the real action would play out in a simpler, flatter cosmos where there is no gravity. Maldacena's idea thrilled physicists because it offered a way to put the popular but still unproven theory of strings on solid footing — and because it solved apparent inconsistencies between quantum physics and Einstein's theory of gravity. It provided physicists with a mathematical Rosetta stone, a 'duality', that allowed them to translate back and forth between the two languages, and solve problems in one model that seemed intractable in the other and vice versa. But although the validity of Maldacena's ideas has pretty much been taken for granted ever since, a rigorous proof has been elusive. In two papers posted on the arXiv repository, Yoshifumi Hyakutake of Ibaraki University in Japan and his colleagues now provide, if not an actual proof, at least compelling evidence that Maldacena's conjecture is true."
I hate to tell you but not all scientists are doctors, and also cancer is not the only issue that is affecting us today. The more we understand about the universe, the more we understand about ourselves.
In other words, what are YOU doing to cure cancer since you think that "scientists" should focus on cancer instead of XX.
have you seen my sig? there are many others like it but none that are the same
So, the headline is quite wrong. Nothing in this work has directly to do with our universe, nor does it show that we live in a hologram. What it does do is provide some further evidence for a string theory conjecture called AdS/CFT. This conjecture says that "string theory in d dimensions" is precisely the same as "conformal field theory in d-1 dimensions". This is cute, since it lets us calculate some things, for example, one might be interested in calculating something in some field theory, but it is very difficult to do. AdS/CFT lets us translate that thing into a string theory thing, which usually is easier to compute. So people working in condensed matter physics, particle physics and QCD are actually using this string theory conjecture as a computational tool. However, AdS/CFT tells us nothing about our universe, since we know that the type of string theories it talks about can't describe our universe. So it is "only" a useful toy model and computational tool. The article is about that some guys have run computer simulations to calculate something on both sides, so both on the string side, and in the field theory side, and what they get match, as it should if the conjecture is true. This is nice and lends further evidence to the conjecture, but there is plenty of other evidence already known, both numerical and theoretical. So I fail to see how this is important or newsworthy, it feels mostly like useless hype.
One can manipulate math to to describe or answer pretty much anything you want. Just because the equations match what's happening does not mean they describe what's going on.
Who cares? As long as the equations match what's happening (and what's going to happen), does it matter what's "really" going on? We've been doing quantum mechanics for almost a century now, and still no one actually knows what it all means - but we're perfectly happy to take advantage of QM in our technology.
Certainly, you can describe anything with equations, and you can come up with multiple mathematical descriptions that match what you know. But they'll make different predictions, which can be tested, and that's where the value of generating a mathematical description is. If you're not looking for predictions you can just say "that's the way it is," skip the math, and move on to something else.