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Strings Link the Ultra-Cold With the Super-Hot
gabrlknght writes "Superstring theory claims the power to explain the universe, but critics say it can't be tested by experiment. Lately, though, string math has helped explain a couple of surprising experiments creating 'perfect liquids' at cosmic extremes of hot and cold. 'Both systems can be described as something like a shadow world sitting in a higher dimension. Strongly coupled particles are linked by ripples traveling through the extra dimension, says Steinberg, of Brookhaven. String math describing such ripples stems from an idea called the holographic principle, used by string theorists to describe certain kinds of black holes. A black hole's entropy depends on its surface area — as though all the information in its three-dimensional interior is stored on its two-dimensional surface. (The 'holographic' label is an allusion to ordinary holograms, where 3-D images are coated on a 2-D surface, like an emblem on a credit card.) The holographic principle has value because in some cases the math for a complex 3-D system (neglecting time) can be too hard to solve, but the equivalent 4-D math provides simpler equations to describe the same phenomena.'"
XKCD
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Lately, though, string math has helped explain a couple of surprising experiments
Yes, that happens all the time. The problem with string theoy is not that it doesn't predict anything. It's that it predicts everything. At least, one of the innumerable variants will predict anything after it's happened. If anyone could pick out some predictions before they happen then that might be something to get excited about.
Yet another physical phenomenon fits the theory of everything. How about a prediction from string theory for once?
Just my $0.55 (US inflation, 1774-2008, for $0.02)
Once you've put Octavarium by Dream Theater on and smoked a fat joint, this will make a lot more sense.
To you, at least.
Finally had enough. Come see us over at https://soylentnews.org/
I think you understand it just fine ;)
String theory is ripe with predictions. The problem is we can't test most of them directly, hence the main problem - lack of falsifiability (see: not even wrong).
The thing is, "God did it" doesn't give you any equations or principles. String theory, while it may turn out to be completely wrong, at least gives us something to test.
Dimensions can have all sorts of zany topologies going out to infinity.
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Well this is closer to "universality", which is a concept in field theory and condensed matter physics, in which the "atomic" characteristics of a system are largely irrelevant to its macroscopic properties, save for specifying a few parameters like viscosity or resistivity. Unlike your differential equation example, the equations for both are very different and non-trivial. When you start enumerating differential equations starting from the simplest you can write down, the harmonic oscillator, heat equation, diffusion equation and so forth pop out right away. You'll be writing for a long time before 11D supergravity equations of motion pop out.
I think the problem is that it is so complicated it predicts everything that can or could happen. So the math is interesting to apply after the fact--but you can't extract the real from the possible results through the math alone.
Having to many points is the same as having none at all. And that's what String Theory in its current form seems to be.
"Ultracold" here refers to degenerate Fermi gases, not Bose-Einstein condensates (BEC).
Here's a layman article:
A Fermi gas of atoms
Deborah Jin
Physics World, 2002
And the original publication by the Duke group:
Observation of a Strongly Interacting Degenerate Fermi Gas of Atoms
K. M. O'Hara, S. L. Hemmer, M. E. Gehm, S. R. Granade, J. E. Thomas
Science Vol 298, p 2179 - 2182 (2002)
If you want to be taken seriously, avoid descriptions like "a shadow world sitting in a higher dimension." It's a meaningless analogy that only serves to make your field sound like pseudoscience BS.
While I am not sure that I agree with the sentiment on religion (we all have our own ways of coping... religion isn't the worst), I think you pretty much got it with string theory. It's disingenuous to call it science. Calling it math would be more appropriate. As a matter of fact, if it must remain a priory because its assumptions are not testable, it must be math. Now calling it religion is probably not fitting the bill. It is still based on postulate-and-then-use-logic-to-deduce paradigm. As opposed to religions' vision-followed-by-political-expedience paradigm. For anyone who wants to argue that "religion uses logic, too," I say "fair enough." But math uses only logic to come up with conclusions. And math can be based on arbitrary assumptions from which those conclusions are drawn (the only restriction is non-self-contradiction). Whereas religion will attempt to use plausible assumptions and then draw arbitrary (from the point of view of logical consistency) conclusions.
Any guest worker system is indistinguishable from indentured servitude.
Here is the thing. There are people that understand it, and can explain it. Just because you need a Phd to understand it.
You are right to be skeptical, but don't confuse not being able to understand something with it not being understandable.
It also make predictions.
There are tests, we need a certain collider to come on line...
The Kruger Dunning explains most post on
...all claiming that String theory is not testable.
To these people, I'd like to point out that:
1] Not being testable with current technology is not the same as not making any testable predictions. Technology advances, after all, and there are predictions that were made by Einstein that are still being tested today.
2] It's flat out wrong to say there is no work being done to test String theory. The LHC will begin to unlock a number of answers in this regard.
I was under the impression a dimension was like a mathematical axis, i.e. infinite in two directions...?
There's no such animal outside theory. In the real universe, spacetime is curved, more or less depending upon local conditions, but definitely never geometric line straight. If it appears that way it's because either the curve is too slow, you are similarly curved, or both. At the most extreme, the theoretical 'closed' universe curves back on itself as if you lived on the inside surface of a balloon.
Taking the lead from this Einsteinian view, string theory says the other dimensions are curved also, but to the extreme -- like to the Planck length or less (the smallest possible "grain" of the universe). The difference is not quality, only in quantity. That balloon you live in? Make it the so small that in size it is to an atom as an atom is to the Earth.
Once you've bent your head around that, consider that due to the Planck stuff, and things like Hawking's idea that near a singluarity (such as a Planck scale phenomenon) time and space fold into each other, no dimension no matter how straight, is an exact integer at all scales. This is true of the usual 4, and almost certainly of the other hypothesized 7. These other than integer dimensions are said to be "fractional". From fractional dimensions comes the word "fractal". And here you thought fractals were just good for producing CGIs of clouds, mountains, explosions and so forth. They are, but it's because they also produce the appearance of the real things.
"I may be synthetic, but I'm not stupid." -- Bishop 341-B
Yah, that's the problem - every theology ever invented can be summed up with one line of code:
If ($cause == $unknown) { exit("God did it!); }
Of course, they all like to pretty it up by adding comments and redefining meaningless variables, but the end result is the same.
Why are people modding this up?
A thin hologram can be represented truly as a 2D surface. You can print a thin hologram out using a laser printer and transparencies. You can even display a hologram on a TFT.
The fact that you don't even understand holograms makes me wonder why you are even commenting on string theory.
It's become very popular these days to bash string theory, yet noone has an alternative.
People like sexconker want to remove grant money from research into any new theory until they have a theory that is complete. And yet it can't be completed with people actually working on it.
The article dorks up the notion of holography by associating it with 3-d holograms. The concept is that you don't need to know whats in the middle if you can draw a border around it and measure the surface of that border with sufficient resolution.
In "near field measurements" you are too close to the source to treat it as a simple point source, or a point source with directionality to its output. Normally you would have to be in the far field (at least several wavelengths of the frequency you're measuring or several times the physical size of the source) to be able to measure it using point receivers. Being in the near field you can't simply scale your measurement to farther distances using the normal spreading formula involving r^2 or r^3.
As an example, sticking a mic 4 inches away from a loudspeaker can't tell you what the sound level will be 100 feet away. Amusingly, the typical 1-meter you normally on stated SPL levels is too close for larger woofers.
Holographic measuring is the concept of putting an array of sensors in the near field surrounding the object and being able to extrapolate far field measurements. There are criteria for the number of required measurement points and spacing based on the distance and frequency you're trying to measure. From those measurements you can determine the far field measurements and make some calculations about whats inside the boundary. One technique is to take all those new measurements, amplitude and phase, and substitute those as individual point sources in calculating the far field sound levels.
It has always irked me how easily people misuse the word 'theory'. Until it is testable, with reproducable results, it will remain 'String Hypothesis'.
Yes there are tests but the tests won't be definitive. One of the problems with string theories is that there are a multitude of them and they very very mutable. The collider will only rule out (likely) or confirm (doubtful) a subset of the possible string theories. However, the remainder of the string theories will be safe from falsifiable experimentation. What is needed but lacking is way to winnow out candidate string theories that a) describe our/the universe, b) solve current quandaries of physics like why certain physical constants have the values that they do, c) make predictions which are practical to confirm, d) are parsimonious as string theories are notorious for introducing several new constants and constructs for every one they explain.
Now I may not be a PhD but I am a taxpayer who is happy to see some of his taxes go to funding basic scientific research. And I agree with those who say that the current fashionability of string theories preclude other approaches from being funded and that string theories are getting a free pass on standards of prediction, observation, and experiment that other branches of science are held to.
Incidentally, a hallmark of all other good theories in physics to date is that all can be represented by fairly simple systems of equations which an Asimov, a Sagan, or for that matter a good HS science teacher can explain to an interested (and research funding...) public. Be they Newtons Law's, Special and General Relativity, or Maxwell's Equations, good theories tend to have a parsimonious tightness to them that practically shout out what experiments one should do next. Now I realize that in the end, that the universe need not conform to such beautiful systems but the fact that to date that it has and string theories most certainly are not give me pause.
The FA at least holds out some hope for winnowing out more implausible string theories (and no the idea that all string theories describe a possible universe cuts zero ice until someone finds a way to observe/test that) at least and maybe showing the way to an actual viable theory that is more than pretty math.
As a rule, if you cannot test something today, and you don't have a working blueprint for a machine that, once built, can test your theory, then you don't really have a testable theory.
This article really is not about string theory. The article is really about the math developed as people have explored string theory. It is this math that has been applied in explaining "perfect liquid" experiments.
May be string theory is the biggest joke God ever played. In order to progress in science, we have to first have faith.
Not only that but my own string theory related theory is that 99% of the posters here bitching about string theory do not have the necessary knowledge of physics and math to actually have a truly informed opinion about string theory. And of the remaining 1% I would venture that only a small fraction have gone to the necessary effort to actually properly evaluate it. But then it's so safe to try and look intelligent by chanting with the crowd; after all everyone around you believes you.
Here's a thought - the right to an opinion isn't a requirement that you have one.
The tyrant will always find a pretext for his tyranny - Aesop
Actually, that's not true. There are alternatives, including loop quantum gravity. String theory has been kicking around for 20 years, and essentially no progress has been made. Therefore it makes sense to stop dumping funding into it that's wildly out of proportion to its level of promise relative to other avenues of attack.
It's gone for 20 years without making a testable prediction. If it went for 50, would you support cutting off funding? 100? 200?
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Actually, most physicists believe the LHC will fail to find the Higgs and in doing so give some hints as to why the Standard Model is broken.
Most physicists are optimistic like that.
How we know is more important than what we know.
My non-technical mother in law is interested in string theory but she has no clue what it's about, except that everything in the universe is made out of tiny "strings" that go into another dimension. She is a retired grade school teacher and knows what atoms and subatomic particles are, and she understands the idea of a line having zero width and a plane having zero thickness. I'm trying to come up with an analogy that will get across the basic idea.
Say the universe is two-dimensional, like the surface of a drum. No thickness, just a plane. Then say somebody outside of the universe pokes a needle through the drum head and pulls a piece of thread through it. The thread is one-dimensional, with no actual thickness, so the place where it goes through is just a point. Nobody who lived in the 2-dimensional surface could see the point because it has no thickness. But what if the thread vibrates like a guitar string... as it moves back and forth, the point where it goes through the drum also moves back and forth. The spot becomes a little line. If the string didn't vibrate exactly back and forth but kind of wandered around in a fuzzy pattern, the point would look like a hazy dot.
Because the string vibrates so fast, the people in the plane of the drumhead would never perceive it as a point, but only as a blurry spot (assuming they could see things that small).
That's what a subatomic particle is in our universe, except in 3 dimensions. Wherever a vibrating cosmic string passes through our universe, it forms a hazy dot-like pattern in space, which to us is a subatomic particle.
I know this is far from exact, but does it give enough of the general idea?
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Yes and no. I read the post and the poster displays an incomplete understanding of the what he's talking about. In some ways, he's wrong, but mostly he's incomplete. I suppose my reply was incomplete for no other reason that I was being a jerk and dismissive.
The first paragraph, nothing inherently wrong there.
The second paragraph about "we think" things have been experimentally verified is where it starts to go off the rails. Relativity and quantum mechanics have both predicted, verified and repeatable results of both experiments and observations.
I'm going to use relativity for a moment here because the OP states that he thinks something is "wrong" with relativity or somehow stands weaker footing than quantum mechanics, specifically because he believes that devices have not been built to explore and demonstrate. No.
Going back to my previous example, relativity predicts that for the velocity and orbit of a GPS satellite, there will be a time dilation amounting to a very small fraction of a second. There MUST be compensation for this discrepancy, otherwise, your GPS unit would be off by about 10kms a DAY. Is this an experiment? No, it's even better. The experimental confirmations took place before. This is an everyday practical application of the Theory of Relativity. We know that in these conditions, what we know holds to be true. There is nothing inherently wrong with either relativity or QM, because in their respective spheres, they work.
The fundamental concept that Areyoukiddingme is misunderstanding is that scientific endeavors are not predicated on the concept that the ideas of the present, and by association the past, are wrong. Newton's ideas as laid in the Principia are as fundamentally sound today as they were during his time. However, at the extremes of mass and speed, it starts to fray at the edges. Does that mean he was wrong? Negative. His understanding was incomplete , which is a very different thing from wrong. As Newton himself was standing on the shoulders of giants, others would build on his theories, all the way up to Einstein and those who followed him.
This is a very important nuance - the elimination of errors in our understanding is a side effect of the purpose of science, which is to increase our understanding. This is a constructive, not a destructive intellectual process.
[Burning Karma]
The problem is that String Theory (or M-theory or Brane Theory, whatever) is a bunch of mathematical models that are cool if you have 11 dimensions, so you have to hand wave about where those 7 dimensions went.
And yet after 20 years of mathematical masturbation, I've yet to see any single prediction from the mathematical models that can be tested.
Not one.
That's not Science folks, that's theoretical mathematics. Which is a perfectly valid academic field, just don't call it physics.