String Theory Predicts Behavior of Superfluids 348
schrodingers_rabbit writes "Despite formidable odds, condensed matter physicists have made a breakthrough most thought impossible — finding a practical use for string theory. The initial breakthrough was made by physicist and cosmologist Juan Maldacena. His theory states that the known universe is only a 2D construct in anti-de-Sitter space, projected into 3 dimensions. This theory manages to model black holes and quantum theory congruently, a feat that has eluded scientists for decades; but it fails to correspond to the shape of space-time in the known universe. However, it does predict thermodynamic properties of black holes, including higher-dimensional viscosity — the equations for which elegantly and almost exactly calculate the behavior of quark-gluon plasma and other superfluids. According to Jan Zaanen at the University of Leiden, 'The theory is calculating precisely what we are seeing in experiments.' Unfortunately, the correspondence cannot prove or disprove string theory, although it is a positive step." Not an easy path to follow: one condensed matter theorist said, "It took two years and two 1000-page books of dense mathematics, but I learned string theory and got kind of enchanted by it. [When the string-theory related] thing began to... make predictions about high-temperature superconductors, my traditional mainstay, I was one of the few condensed matter physicists with the preparation to take it up."
Science Fiction (Score:2, Insightful)
Re:Yeah... (Score:5, Insightful)
Re:Science Fiction (Score:4, Insightful)
Umm, you've just described all scientific progress both past, present, and future...
Re:Science Fiction (Score:1, Insightful)
I thought "both" was only used to describe two items.
Re:Yeah... (Score:1, Insightful)
"I don't like what it could mean, therefore, it's a negative thing."
Re:Wow (Score:4, Insightful)
It's because they look at how huge the universe is, how much energy is in it, how long it's all been around, how long it will most likely continue to be around, then truly comprehend how small, short-lived, and insignificant they are in the grand scheme of things.
That kind of realization will humble anyone, no matter how smart they are.
Re:Wow (Score:5, Insightful)
Very simple explanation - nothing in the universe builds humility like an education in physics. If you don't walk out of a physics degree feeling like you know less than you did when you started, like all you've done is build layer upon layer of model and gained only modest flashes of insight into reality after marathon sessions of math, then you've done something wrong.
Re:It's the math, stupid (Score:5, Insightful)
Any statistician will tell you that if you put enough free parameters in a model, you can calibrate it to the given data. Admittedly, string theory has some impressive parts to it, but it seems like it's just excess parameter fitting for a class of models that can all explain roughly the standard model.
But if somebody does come up with a particular string-theoretic model with new, testable implications that get verified that would be impressive - it would certainly indicate that they are barking up the right tree rather than just working on a pleasant geometric abstraction that can be set up to reduce to the messy realities of our fundamental forces and particles.
Re:I don't understand (Score:1, Insightful)
How many times till this joke becomes lame?
Re:It's the math, stupid (Score:4, Insightful)
So where's the competing theory, the one that explains things better, and is testable and whatnot? I hadn't heard that there really was one. My impression was that the one advantage the String theorists have is that they currently don't have any credible competition, though I confess that I haven't been keeping up with the debates.
Re:Science Fiction (Score:3, Insightful)
To be fair, the same could be (and was) said of Quantum Physics as well. Reality *is* fucked up after all.
Pity, Newton's equations were *so* much easier...
Re:Yeah... (Score:3, Insightful)
It taking another step towards that theory good?
If it's correct, then yes, of course. Good luck with your chicken finger theory!
Re:Only a 2D construct in anti-de-Sitter space! (Score:5, Insightful)
Gah! That's so common in technical topics on Wikipedia. The problem is that it is is written by undergrads and interested amateurs (I know, I'm one of them). Often they don't know the subject well enough to simplify it for a general audience, and are stuck putting it in the same language they learned it in. Simplifying a complex topic generally takes quite a degree of mastery, in order to know which simplifications are justifiable, and which would distort the concept too much.
Also, I think sometimes they like to show off by writing things people can't understand.
Give it time (Score:3, Insightful)
Everybody gives string theory a hard time because it hasn't made any predictions, and because it can't be tested. Give it some damn time. It took ages before anyone could make useful predictions with quantum mechanics, and it was shunned for a while too (even by Einstein) and now it's an essential part of our scientific understanding. We shouldn't be so quick to cast out string theory either. Some time, eventually, maybe very far down the road (and if it turns out to be right), it too could be as useful as quantum mechanics has become. I wish scientists would just open their damn minds for once.
Re:Yeah... (Score:3, Insightful)
That is to say, if you view that the proving of string theory to be true a positive step.
Pardon me for the semantics, but no science/scientific theory can be "proven" - even the theory of gravity can't be proven. If I take a rock and drop it on my desk a million times, that doesn't prove that it'll fall there again on the 1e6+1th time. The same goes with the theory of evolution: nothing can prove evolution, but we just have a lot of evidence (fossils, experiments, etc.) that support it. A theory is supposed to make robust predictions, not sense. You can't understand science, you can only apply it. Classical mechanics can't make sense of blackbody radiation or the photoelectric effect, but that doesn't mean that it's wrong, just that it's not useful on a quantum scale. String theory itself probably only has some realm of physics/dynamics that only it can explain that just doesn't make sense/isn't useful in the realm that we try to understand it in now.
Re:Yeah... (Score:5, Insightful)
Your point about semantics and the word proof is understood. Of course, you are conflating proof in a mathematical sense with scientific proof. Scientific theories are proven repeatedly, when testable predictions are confirmed. (This is the traditional use of the word in science) They can still be disproven, but scientific proof is very different than mathematical proof. Of course, proof in the common sense meaning of the word is a completely different idea, and yet a third thing. If you're going to make semantic points, make sure the words you use are the ones you want. "Proof" is a bad one to pick apart semantically, because there are a couple different meaning depending on context and meaning. (Yes, in the same context, the same word can mean 2 different things. That's language for you.)
Of course, you then stop making sense. One CAN understand science. See many comments of Feynman about just that point.You may think you are a scientist, but you seem to think about science a hell of a lot like an engineer.
Re:String Theory Predicts Something? (Score:5, Insightful)
but then complain:
If theorists are continually modifying their theories in order to fit with experiment/reality, and rejecting theories that don't fit with experiment/reality, then what's the problem? At that point it's not "just math", it's "math that correctly matches reality and makes predictions", which is the gold-standard in physics.
Now, you may disagree with the particular mathematical formalisms the theorists are investigating, or the particular order in which they are checking them... but I don't understand how you can be upset at them for continually making changes in order to fit their theories with reality. That's what theorists are supposed to do: investigate a wide and wild variety of mathematical theories, and see which ones are able to make useful predictions consistent with experiment.
Again, this is an objection of procedure. If you can think of a faster way to uncover a mathematical theory consistent with all known experiments, then describe it. Until then, what's wrong with theorists checking a wide variety of theories (adding and subtracting terms/elements/dimensions as they go) until they find one consistent with observed reality?
(And of course, in reality theorists are not performing the random-walk through theory-space you describe. They have very good reasons for checking the equations they do; their analysis is informed by many experimental results, previously-successful theories, and the structure of mathematics itself.)
Re:Yeah... (Score:0, Insightful)
The problem with calling it "proof" is that it has the connotation that it is Truth. When in reality it merely models what is observed. Truth is unattainable in this universe.
Re:Science Fiction (Score:3, Insightful)
That's why this could be a big thing. If it's making actual testable predictions, you can almost call string theory a science. It's a massive breakthrough for the last decade of seemingly-pointless navel-gazing.
Re:Yeah... (Score:3, Insightful)
So, the ONLY think this particular variant of string theory has been good for is modeling "higher-space" viscosity. It could never be used as a Unified Theory because it already has an obvious flaw.
Re:It's the math, stupid (Score:5, Insightful)
That's basically the, 'If you can't completely and convincingly prove my wild theory wrong, then it must be correct' argument.
"If God isn't real - then how do you explain ________"
'Well, I can't explain ________ but I'm saying that there are problems and contradictions in your religious beliefs like,'
"BWHAHAHA GOD EXISTS BECAUSE YOU CAN'T EXPLAIN WHAT STARTED THE BIG BANG".
A lack of a better theory doesn't make a theory right.
Re:Wow (Score:3, Insightful)
Having a physics undergrad degree myself I always felt this humility was due to quantum mechanics. It is just so bizarre and so far removed from everyday common sense that physicists have to live every day with the realization that the universe *is* stranger than we can suppose. Pretty humbling.
But also, it may be due to a much more rapid set of paradigm changing events in physics as compared to other sciences. Within the last 150 years physics has gone from renowned scientists saying that "we've almost discovered all there is to discover" to Relativity, Quantum Mechanics, steady-state to big bang, dark matter, dark energy, and possibly more that I'm leaving out. When phycisists can look back in relatively recent memory and see such changes as well as titans say things like "God does not play dice with the universe" to seeing proof that, well he does [wikipedia.org], why should anyone be cocky?
Re:Yeah... (Score:4, Insightful)
You can't simplify something until you understand it. Once we have a GUT it will probably reduce to PIRcubed of the universe expanding.
Re:Wow (Score:5, Insightful)
"The grand scheme of things", yeah, I love how people compare themselves to the hole universe as if it somehow was the objective way to look at things.
I don't compare myself to the whole universe, I compare myself to elemental particles. In that tiny scheme of things, I'm giant made of tiny molecules that make up cells that make up tubes and organs and shit, which millions of organisms and such living in me. I'm a world of its own.
I'm being serious here, I don't get how people can go "oh look I'm so much smaller than the whole fucking universe, and so much younger too, that just blew my mind". I for one don't see how the size of the world you live in is relevant to what you are. That's just a misplaced point of view to look at yourself from. Also, I think it's just an exercise of mental masturbation in the dimensions abstractions department, i.e. it's hard to really picture to ourselves what large numbers really represent rather than just a bunch of zeroes, so the exercise of picturing how many times bigger than you the universe really is is humbling, but still completely irrelevant to your life. The universe could stop 50 kilometres up in the sky, it could be only 6000 years old, what would it change to you?
Re:Wow (Score:1, Insightful)
String Theory doesn't predict anything. Therefore, it should not be mentioned in the same sentence as quantum mechanics.
Actually, there was a recent article that says string theory predicts behavior of superfluids.
Re:String Theory Predicts Something? (Score:3, Insightful)
> Well, it helps by ensuring that less energy is wasted pursuing it. See?
So... basically you'd call a halt to all theoretical physics since none of the current new theories are currently testable, and won't be without further investigation.