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String Theory Predicts Behavior of Superfluids
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."
That is to say, if you view that the proving of string theory to be true a positive step.
Is it just me or does String Theory really sound like someone is making it up as they go along. It's like: "we haven't a clue whats going on but reality's so wierd we've decided to pull a theory out of our ass!"
I have a theory that there must be a joke in here somewhere about strings and superfluid!
is string theory something to do with that thing in space in Star Trek: Generations?
I'm always amazed that theoretical physicists can manipulate such immensely complex abstract objects in their heads and still be able to breathe and maintain bladder control. It really makes software engineering look like a piece of piss. Much respect.
I would also say that having worked with academic medics, chemists, mathematicians, computer scientists and biologists, physicists are almost always the coolest, most down to earth and least douchey scientists out there.
the known universe is only a 2D construct in anti-de-Sitter space, projected into 3 dimensions
Well if THAT'S all it is, I see no reason to upgrade my video card.
Rich And Stupid is not so bad as Working For Rich And Stupid.
String theory works because the math works. There isn't anything special about the string theorists' model of humming cosmic strings that makes it work. All particle behavior is explainable using mathematics.
What makes this interesting is that the model allowed for the construction of mathematical constructs that explain the behavior correctly. But it still doesn't say anything about the predictions that the model completely blows.
What String Theory has, more than anything else, is a great set of marketeers behind it. Michio Kaku is a smart and articulate guy. It's not the steak, it's the sizzle.
on page 642 of the second book, they divide by zero, so back to the drawing board.
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.
Boy, long winter evenings must just fly.
"A door is what a dog is perpetually on the wrong side of" - Ogden Nash
String theory was originally conceived as a theory for QCD, and only later was it applied to quantum gravity. Here (http://physics.aps.org/articles/v1/10) is an article which explains the new results with a little historical context.
The Maldacena duality can't be used to 'make predictions' with a string theory, its just a correspondence between a string theory and a conformal field theory. It's useful because sometimes calculations which are hard in a CFT can be made in the corresponding string theory which is sometimes easier (or vice versa). It cannot be used to support the physical validity of some string theory.
I read TFA and just thought "as you do..."
Surely any discovery, either for or against prior ideas is a step forward and thus positive. It's the scientific method - proving yourself wrong is just as big a success as proving yourself right. It's the proof that is important :)
No, really I don't. "space-time has any number of dimensions, usually 10" USUALLY?! What is anti-de-Sitter space anyway? What? WHAT? WHAT THE FRELL?!?!!111one
except the datum of there being _at_least_ 3 spatial dimensions.
hehe...almost exactly...doesn't seem to be correct then...
i just uninstalled your linux.
The main criticism of string theory is that it is too flexible. It can be contorted to generate any prediction, so it predicts nothing. This problem is not unique to physics; I saw it in economics too. Add more parameters to your model and you can fit historical data better, but your predictions of the future get worse. TFA seems to be just a string of examples of contorting string theory to fit past experimental results.
But can it predict superfluity?
:P
The holographic principle doesn't mean that the universe has only 2 spatial dimensions, but rather that the universe can be modeled using one less degree of freedom than our view of spacetime would imply. Again, these kinds of theories are not suggesting that our space is two-dimensional, rather they are saying that the 3 dimensions we observe are emergent from a lower-dimensional description. All of the 'information' in a given region of space can be described as being encoded in the surface of said region.
This remarkable, if bizarre, conclusion gains considerable support from the fact that black-hole entropy (and entropy is a measure of information content) is related only to the surface area of the black hole. So this is a case where we know with some confidence that we can indeed reduce all the information about a 3D region of space (the black hole) to an expression that only relies on 2 dimensions (the surface of the black hole). The holographic principle appears in numerous theories that imply that this holds generally for any region of space, not just black holes.
Now, whether you view this is 'just a mathematical trick' or 'a deep insight into the actual structure of the universe' is in some sense a matter of taste. (The same goes for all other physical theories: e.g. do electrons exist or are they just mathematically-useful constructs? How about photons? Gravity waves? Spacetime?) If you take the math seriously then this may mean that our universe is in some sense 'actually' 2-dimensional, with the three spatial dimensions we see being emergent instead of fundamental.
But in no case is the theory saying that there are not 3 spatial dimensions. The predictions it makes are for particles moving through a 3+1 spacetime.
See live long enough and you do get proved right now how do they explain the horizion?
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.
I have left slashdot and am now on Soylent News. FUCK YOU DICE.
The major problem with String/F/D/Dn/S/Brane/M/Multiverse/Whatever's-next Theory is that every time someone finds a problem that doesn't fit with experiments/reality they just go and find an excuse and then modify the equations until it mathematically works out in that general direction. They don't start with the latest and greatest and modify that. They just pick their favourite Theory-of-the-day and add an extra dimension here, or there, twist it there, or subtract another infinite from both sides, because the formula is inconveniently looking incorrect at the moment. In other words, Just squish the Jello a little here and make it come out over there instead, until someone discovers 'the new mess' on the floor.
If a theory has no basis in fact (i.e. no physical reality that can be described) then it is just Math. Math is not reality. You can model anything with Math, and it doesn't even have to exist.
I have no idea what I'm saying.
"I'm a Genius!"*
*Not an actual Genius
Folding 10 dimensions down to four can be done in a mind-boggling 10^500 ways
Jeah, I'm not a physicist and I know, that I'm spoiling my karma right now, but seams that they just made up some very generic "function" with N attributes and every time result does not match, they say- "Hei, change that attribute" or "Take 8 dimensions instead of 10" or "Fold 5th dimension that way". Come on, even y = ax^2 + bc + c almost match with y=sin(x) in some particular region of x if you set up a's, b's and c's correctly.
Source/reference?
You're a non-Newtonian fluid
The kind you can't take home to moth-tha.
And everyone agrees that it STILL doesn't make sense.
I am now totally convinced that Douglas Adams wrote this universe.
"Do you know string theory?"
"No, I'm a frayed knot."
"Omnis tuus capsa sunt inesse nos"
I am feeling REALLY unintelligent after reading the summary. I'm not even going to try to RTFA.
This space for rent...
anything that comes up with an anti stiller space must be good.
hey! that's what I read on a very small phone screen!
All you can say really is that the evidence fits the hypothesis, and therefore it hasn't been proven false.
Think of it like sculpting. Eventually after you chip away all the junk you are left with a shape, or model which looks like the truth. You can't say it *is* the truth, but it sure looks a lot like it.
Deleted
Except Sheldon Cooper.
Spaghetti is tastier than string, and they could unify biology and physics with AdS/FSM spaces. How many dimensions has His Noodly Appendage?
As always....xkcd explains it best here.
Motorcycles, Robots, Space Gossip and More!
You see, there's a magical pony pony, represented by the variable P. And there's magic, represented by the variable M. And there's everything, represented by the variable E.
P + M = E
Ha, motherfucker! Magical pony theory beats all!! I have the math to prove it.
The problem with string theory is that exists in its own little world of mathematics. And you're allowed to relentlessly massage the mathematics until one day you can jump up and say, "Look, my math proves _________!"
And then when someone says, "Well what the hell does that have to do with the observed universe?" some jackass will come along and start rambling on about some crap like holographic representations of dimensions. "So, you see, you can represent five dimensions in a universe that appears four dimensional because the fifth dimension was tucked under your pillow by the tooth fairy. And the sixth dimension is under the pillow, tucked away in a fold in the sheet."
So, fuck it. I say the seventh dimension is tucked in the ass crack of the magical pony, the bringer of all things.
I scream. You scream. I assume that means we're both acquainted with the problem. We proceed.
I am glad someone else brought this up because I am tired of doing so in these discussions. But I see that you have not been vilified for bringing it up, as I have so often been.
Think about it in comparison to "counting" which everyone does every day, and the *THEORY* of mathematical systems (rings, fields, etc.) which are abstractions of counting.
The value of an abstraction is that it can eliminate bias in thinking; we all try to map our perception of reality onto a model. When we create an abstraction, it enables us to think about the model in the absence of reality. Then, when one gets interesting results, one can then attempt to map them back to reality, and examine what that means in the real world.
It was the development of number theory and the abstraction of counting that led to the understanding of number systems, base 10 and base 2 arithmetic, and binary arithmetic, the basis of today's computing engines.
But you all knew that.
After my B.Sc in Psychology, I finally understood that we are not only weird illogical animals, but also that we don't know who we are. Then you get your degree and you go outside, you look at everyone running around and you see something totally different than when you first began your studies...
Sentences like this are silly: "His theory states that the known universe is only a 2D construct in anti-de-Sitter space, projected into 3 dimensions."
No, the Universe has 3 spatial dimensions and one for time. If you take spacetime seriously, writing software to animate equations in 3D space + time, then you can get visual insights into physics that make sense.
Take EM. It has a symmetry called U(1), but non-technical people can understand it as a circle (in the complex plane for the technical folks). If you have an electrical charge, then you have a circle in a complex plane so you have the symmetry U(1), visualphysics.org/forums Why is electric charge quantized? Because you can count circles.
Doug
http://VisualPhysics.org
Working on new views of old physics at http://VisualPhysics.org
When will these scientists realize the cubic properties of time and space?
You're not thinking TWO-dimensionally!
http://xkcd.com/171/
Science can't help you find it, because science deals with theory, not Truth. Religion won't help you find it, because you haven't lost it. In general though, we don't want big T Truth, we want a convenient little truth we can carry around in our pockets and show off when we want to impress someone. Big T Truth is too damn simple, and you can't show it to people. Of course, what I've written is theory, not Truth.
- None can love freedom heartily, but good men; the rest love not freedom, but license. -- John Milton
But Newton didn't have a computer.
s = "string" .. 2 ]
# "string"
s[ 1
# "tr"
s + s
# "stringstring"
s * 3
# "stringstringstring"
s.reverse
# "gnirts"
s.upcase
# "STRING"
http://xkcd.com/171/
... that get's to peer review the 1000 pages of math?
they are saying that the 3 dimensions we observe are emergent from a lower-dimensional description.
You know what that reminds me of? Computer data storage. All data in any form or dimensions is ultimately represented as a 1D string of bits/bytes in a computer.
So maybe all that means is that you can work something out to turn the universe and all its dimensions into a single thread, but as you said that's just a way to look at things.
As for the black hole entropy, not like I have any insight on the matter, but you said "we can indeed reduce all the information about a 3D region of space (the black hole) to an expression that only relies on 2 dimensions (the surface of the black hole)", and it reminded me of how I have a quibble with people claiming that the surface of the Earth is in 2 dimensions because we only need two coordinates to locate a point on the surface. It's not in 2D, it's in 3D polar coordinates, it's just that the distance is always the same, so we discard it and only keep the two angles. So, just saying about your black hole comment, it's not because one of the three coordinates in a 3D space isn't of any use that it ceases from existing.
You just got troll'd!
The one thing we can be certain of, is that String Theory is still just a theory. Which is why we demand that mathematic departments give equal time to our "Intelligent Variable" theory, and let the children decide for themselves.
... but this quote:
"but it fails to correspond to the shape of space-time in the known universe."
Kinda puts the nail in the coffin of this evidence for string theory now doesn't it. I really wish that they guys would just shut-up, stop grasping at straws and go away. At least until they actually find something useful that fits known Physics and doesn't contradict it in some significant way.
The surface of a sphere is 2D, and the surface of the Earth is very close to 2D (but probably fractal). When we talk about the dimensionality of a generalized volume, we generally aren't interested in the dimensionality of the Cartesian space it is embedded in, but rather how many parameters we need to define a point. If a particle moves in 3D but has a single holonomic constraint (in the case of a sphere, fixed radius), the surface it moves through is 2D. (more generally, we could use the fractal dimension).
Now, in modern physics, Cartesian coordinates aren't regarded as especially holy. You are considering Earth as 3D because you are saying that Cartesian coordinates are what really exists and polar coordinates are a human construction. But when you study enough physics, you realize that physics is just a tool to model how the universe behaves, and one cannot assume various intuitive concepts represent the ultimate reality. The 3D Cartesian space seems so natural because it fits well with our personal experiences, but, at a more fundamental level it's not necessarily better than some other system of generalized coordinates.
There has been talk of how string theory is 10 or 26 dimensions or something, and this concept hasn't been effectively communicated to the layman.
In physics we often describe a system of N (spinless) particles as 6N dimensional, because each particle has a position and a momentum, so there are 6N degrees of freedom. The reason we can pick out that there's actually 3 space coordinates rather than 3N is because many particles will interact if their position coordinate is close to the position coordinate of other particles, so they actually must be somehow in the same space. But if the particles don't interact due to distance, there's no way to show that these dimensions are the same thing. Now, if there are more complicated interactions, there might be some way to show that there's actually 2 space coordinates because the 3rd is redundant. I kinda doubt that, but I think that's what they are getting at.
Whooosh!
You are considering Earth as 3D because you are saying that Cartesian coordinates are what really exists and polar coordinates are a human construction.
Nope, I say that discarding one of the coordinates in either Cartesian or polar coordinates just because they're useless is a human construction. Altitude magically pops up again when it becomes relevant again. The Earth is in 3D, no matter how you look at it. You have to discard something for it to only be 2D.
Also I must disagree with N particles being 6N dimensional. That's like saying a colour raster picture is 3N dimensional (N being the number of pixels). First of all I don't know what you would call that but a pixel's colour isn't 3 dimensions, its a position in a 3D space. Same thing for a particle's position and momentum, each are 3D values, not dimensions, because they can only be one value at the same time. That's like, a sound's sample is not a dimension, it's a value, but a sound's instant frequency (if we'll pretend there's such a thing) is a dimension, because it's a full dimension with lots of simultaneous values. A value is in 0D, and 6 times 0D is still 0D.
You just got troll'd!
Maldacena duality is discussed for more then ten years already, "dual black holes" on the RHIC is of 2005 and application to the superconductors is of 2007. So why now ? Are there any new development? Or it's just slashdot catching up on the tow years old news?
"Understanding these materials at the deepest level involves calculating how huge numbers of particles interact - something that we simply don't have the tools to cope with. "It's very dissatisfying that in the centuries since Galileo kick-started modern physics, we still can't deal with that," says Sean Hartnoll, a string theorist at Harvard University."
Huh? I guess they haven't yet asked John Carmack if he could help out.
Ok, yes, but the point is that you don't for black hole entropy - the 3D structure is exactly determined by values on a 2D surface; it's theoretically impossible for two different black holes to have the same values on that surface but somehow different entropy "inside".
(Something I'll mention because it seems relevant: the string theorists' view that space is 10D but looks 3+1D on large scales is very much analogous to the surface of the Earth being 3D but looking 2D on large scales)
Same thing for a particle's position and momentum, each are 3D values, not dimensions, because they can only be one value at the same time.
At a particular instant obviously the particles will be in one configuration - a point - which is indeed 0-dimensional. But that's just a single point in the space, just as for a particle moving in space, its current position is a 0-dimensional point in 3-dimensional space. Suppose we're considering the evolution of the system in time - the particles are moving around according to some trajectories. Now, the obvious way to view this is as a set of N different trajectories in 3D space. But we can also, absolutely equivalently, view this as a singletrajectory in 3N-dimensional space - and this representation has advantages for certain problems.
I am trolling
Would this AdS/CFT correspondence provide any further insight into something like fusion reactions?
seems a little like using differentiation to find the gradient of a straight line... except we know differentiation works
Wow a 5D /.er promoting a 7D. o.0 How rare is that!
The RedVines Theory of the Confection of the Universe can model Superfruity Goodness as embodied in the Skittle particle, or the JuicyFruit Dynamic Flavor Field, and many others due to it's inherent flexibility.
Alas, so far, it cannot predict where we might look for as yet undiscovered Superfruity Goodness, or how many grams of simple carbs such a structure might have.