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Math Science

Strings Link the Ultra-Cold With the Super-Hot 236

Posted by Soulskill
from the words-of-one-syllable-please dept.
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.'"
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Strings Link the Ultra-Cold With the Super-Hot

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  • Of course (Score:4, Insightful)

    by Anonymous Coward on Tuesday April 14, 2009 @05:59PM (#27579203)

    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.

    • Re: (Score:3, Interesting)

      by linzeal (197905)
      String theory to me is like those search algorithms that you run into that are utterly unique yet confounding to parse but get the job done somehow and no one feels smart enough to question half the time. A modified standard model works for me, with some of the new phenomenologies [arxiv.org] emerging based on it.
    • Predicts Everything (Score:3, Interesting)

      by DJ_Adequate (699393)

      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.

  • Lovely (Score:5, Insightful)

    by jimmyswimmy (749153) on Tuesday April 14, 2009 @06:00PM (#27579223)

    Yet another physical phenomenon fits the theory of everything. How about a prediction from string theory for once?

    • Not even wrong! (Score:4, Insightful)

      by FibreOptix (1028122) on Tuesday April 14, 2009 @06:21PM (#27579521)
      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).
      • by delt0r (999393)
        Black holes at the energies that LHC will reach is only a possibility under string theory. So its a push in the right direction. However not finding black holes does not disprove it.

        But lets not get a head of our selves. We have cracks in the standard model, and who knows what the LHC will throw up.
    • Re:Lovely (Score:5, Funny)

      by Stickerboy (61554) on Tuesday April 14, 2009 @06:22PM (#27579531) Homepage

      >Yet another physical phenomenon fits the theory of everything. How about a prediction from string theory for once?

      You'll find that in String Theory 2: The Search For More Grant Money...

    • by Renraku (518261)

      String theory actually makes plenty of sense, if you read into it.

      As we delve into the smaller and smaller, we're going to find out that things that we observe start out in three dimensions. Then they go down to two dimensions. Then one dimension. Who know's what's beyond that.

      If you read "Flatland" by Edwin Abbot Abbot, you might understand.

      Imagine your drive to the nearest Walmart, in 3d. Now imagine it in 2d. Can you imagine it in 1d? I thought not.

      • Can you imagine it in 1d? I thought not.

        That's only because they don't do drive through Walmarts (that I know of).

  • string analogues (Score:3, Interesting)

    by rlseaman (1420667) on Tuesday April 14, 2009 @06:05PM (#27579323)

    "The point is that we have two different kinds of systems capturing the same kind of physics," says string theorist Clifford Johnson

    Back in the day it was commonplace to construct analogs of mechanical systems, for instance, using electronic components [vwh.net]. If the differential equations describing the two systems are similar, so will their solutions be.

    That the topic is string theory is also reminiscent of how soap works [elmhurst.edu]. Half of a soap molecule is soluble in water, the other half insoluble - thus bridging between wet and oily substances. Very yin and yang.

    • Re:string analogues (Score:4, Interesting)

      by DirtySouthAfrican (984664) on Tuesday April 14, 2009 @06:28PM (#27579629) Homepage
      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 still don't understand anything about string theory. Thank you /. for once more making me feel stupid.

    • Re:Yup (Score:5, Funny)

      by CarpetShark (865376) on Tuesday April 14, 2009 @06:16PM (#27579465)

      I still don't understand anything about string theory.

      I think you understand it just fine ;)

    • Re: (Score:3, Funny)

      by Kreigaffe (765218)

      It's ok! Just stop saying that one thing, and start saying.. well.. all kinds of other thing. Use long words and treknobabble, just string it along until everyone glasses over. That's how it was named, you know. String 'em along. Yep.

      You read it on the internet, it must be true!

  • by L4t3r4lu5 (1216702) on Tuesday April 14, 2009 @06:15PM (#27579449)
    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.
    • by genner (694963)

      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.

      Sooo.....The Answer Lies Within.

    • Re: (Score:3, Informative)

      by harry666t (1062422)
      Try "You shouldn't do that" by Hawkwind :)
  • Hang on (Score:2, Interesting)

    by Anonymous Coward
    Hang on a minute... "Similarly, the extra dimensions that strings require would probably be far too small to detect by available methods." What? I was under the impression a dimension was like a mathematical axis, i.e. infinite in two directions...? I keep seeing a lot of articles on this sort of low level physics and mathsy stuff, and I'm not sure if I'm not understanding it because it is too complicated, but I'm starting to think the reporters are dumbing everything down and trying to explain complicat
    • Re: (Score:3, Informative)

      I'm just a layman, but from what I gather the extra dimensions are supposed to be circular rather than "linear", like the ones we commonly use. The circumference of these circles is very small (Planck length).
      • To reply to myself :) But an example just came to my mind, think of a point on the surface of a torus. You can describe the location of any single point on it with two numbers, i.e. two angles (one from the center of the torus, and one from the center of the torus "tube"). If you describe it like this, then both of your dimensions are finite.
        • Re:Hang on (Score:5, Insightful)

          by emarkp (67813) <slashdot AT roadq DOT com> on Wednesday April 15, 2009 @01:29AM (#27582905) Journal

          [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.

          • Re: (Score:2, Funny)

            by Anonymous Coward

            [Burning Karma] = Please mod me up?

    • Re:Hang on (Score:5, Informative)

      by FooAtWFU (699187) on Tuesday April 14, 2009 @06:26PM (#27579613) Homepage
      Imagine the surface of a typical PVC pipe. It's long in one direction (perhaps infinitely long, probably not though) but in the other dimension it's actually kind of small - it's sort of "rolled up". Keep going around and you loop.

      Dimensions can have all sorts of zany topologies going out to infinity.

      • Not quite.

        Instead you have to imagine that the PVC pipe has holes, which are actually tori in a lower dimensional realm(Think of the dark realm in a Link to the Past, or Soul Reaver). Across the dimensional planes, these tori and intersect the pipe (and each other!) to form a condensed PVC hyperpipe, the net result of which is akin to the creation of time before the big bang. If you now simply allow time to exponentially decay in directions perpendicular to its normal flow, you obtain what we understand to

        • by sjwaste (780063)
          I want some of whatever's in your PVC hyperpipe. Seriously, though, that's a pretty good explanation. I still don't fully understand it, and I've read as much as I can handle on the subject, but it's a good analogy that I haven't seen before.
    • Re:Hang on (Score:5, Informative)

      by DynaSoar (714234) on Tuesday April 14, 2009 @07:20PM (#27580277) Journal

      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.

  • ...math for a complex 3-D system ...

    was probably meant to be "complicated". "Complex 3d" means C^3... or (R+iR)^3 if you prefer.

  • That still doesn't explain string cheese. :P
    • I hope someone invents superstring cheese. That bosonic mozzarella they using for the normal stuff tastes like ass.

  • by artor3 (1344997) on Tuesday April 14, 2009 @06:50PM (#27579885)

    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.

    • Problem is: What's with cases, where reality sounds even worse than pseudoscience BS?

      I think -- irrespective to the usefulness of experience-based prejudice -- there's something wrong, when you judge a theory by how it sounds.

    • by tixxit (1107127) on Tuesday April 14, 2009 @10:27PM (#27581915)
      They are trying to explain a concept to laymen. It is not easy. Put another way, shadows on a floor live in a 3 dimensional (2 space + time) world, but the movements and behaviour of those shadows are actually better described in a 4 dimensional (3 space + time) world. In other worlds, a shadows movements are better described by considering them as projections of 4-d objects, rather than 3-d objects. Think of the shadow of a quarter flipping. In the shadow world, we see an object that is continuously shrinking down to a thin line then expanding again to a circle. It seems weird, and the equations to describe the movement/shape through time would not be trivial. However, when we add an extra dimension, we realize we can actually model the movement/shape as a simple rotation of a rigid body.
  • If it isn't testable it has no place in science.

    Study it if it makes you feel good, but understand that you're not practicing anything scientific.

    • by JohnFluxx (413620)

      So basically you'd cancel all research into future theories? Real nice.

    • That's not true.

      As long as it is "faliable' then it has a place in science.

      If the theories advanced by the JudeoChristian tradition had been verified by empirical evidence then the bible would be valuable as a scientific tool.

      Similarly if there were wizards and witches harry potter would be a useful tool.

      String Hypothes--eerrm--theory is perfectly valid in science. Just so long as we recognize that it's speculation. Speculation is valuable. Speculation that becomes dogma. That's a problem. After all the

  • Mathematical mental masturbation does not constitute a scientific theory. I need to see hypotheses and tests before I will even consider giving these models the honor of being called a theory.

    And you wonder why so many people believe ID proponents when they say that Darwinian evolution is "only" a theory.

    • Mathematical mental masturbation does not constitute a scientific theory.

      As opposed to mathematical physical masturbation? Like using a slide rule?

      • by genner (694963)

        Mathematical mental masturbation does not constitute a scientific theory.

        As opposed to mathematical physical masturbation? Like using a slide rule?

        Must....resist..maiking joke....about calculating.....logs.

  • by StevenMaurer (115071) on Tuesday April 14, 2009 @07:13PM (#27580217) Homepage

    ...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 [blorge.com] 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.

    • Re: (Score:3, Insightful)

      by cmat (152027)

      I think the issue with the testability of String Theory is as follows:

      In a theory, there are generally variables. For example, in General Relativity, there are "constants" (called such because they are measured via experimental science) that emerge from the theory. These "constants" are actually variables in General Relativity (if you were to set them to different values you would have a different "universe"). However the important thing is that "variables" that we had yet to measure which the theory pred

    • by martin-boundary (547041) on Tuesday April 14, 2009 @08:02PM (#27580729)
      Sorry, but being conceivably testable is not the same as being testable. If I only had a ghost detector, then I could detect ghosts. Ergo, ghosts are a good theory to work on!

      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.

      • You take take something obviously false like ghosts and attempt to compare it to whatever you'd like to cast disrepute on. Classy. Second, to have a ghost detector, you're required to first know that ghosts exist (otherwise then your ghost detector isn't really a ghost detector).

        Also, you don't seem to recognize the long history of advances in science which were purely mathematical to begin with. For example: Black holes were first predicted mathematically, without any observations to back it up. Did s

      • Slashdot appears to have cut off a sizable chunk of my post, so allow me to continue with a 2nd post...

        Yes, direct evidence is unlikely, but we've got enough indirect evidence to prove black holes & neutron stars exist, so it's not unreasonable to assume that we could find sufficiently convincing indirect evidence for string theory.

        Lastly, the use of the world theory here is arguably legit. Not in a scientific context, but rather in a mathematical context. Ever heard of Set theory, game theory and cha

    • Name one prediction of string theory that could be tested with any technology. In other words, name one prediction of string theory that if found false (in any way) would disprove string theory. I'll give you a better one: name one prediction of string theory.

      And just to cut short one level of string-theory silliness: "there might be 11 dimensions, but if there's not then we can still make the theory work with four" is not a prediction.

      Because of theoretical advances and other sources of investigation, most

    • by Have Brain Will Rent (1031664) on Tuesday April 14, 2009 @09:18PM (#27581513)
      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.
  • by fluffy99 (870997) on Tuesday April 14, 2009 @07:46PM (#27580591)

    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.

  • by jholden215 (939343) on Tuesday April 14, 2009 @07:48PM (#27580607) Homepage
    It has always irked me how easily people misuse the word 'theory'. Until it is testable, with reproducable results, it will remain 'String Hypothesis'.
  • Okay, I get that string theory is much more elegant and being merely and engineer, mathematically well over my head, but this is getting a little ridiculous. I'm having a difficult time recognizing string theory as science.

    Has string theory truly helped us understand anything better? If it has improved our understanding, what predictions of physical phenomena have come of this increased understanding of the physical universe? If your theory can only explain, not predict, aka No Predictive Power, then it

    • Has string theory truly helped us understand anything better? If it has improved our understanding, what predictions of physical phenomena have come of this increased understanding of the physical universe?

      I'm not a physicist, so my understanding is very limited, but the answer to you question is "probably yes".
      The thing is the phenomenon string theory help understand and predict is not related to quantum gravity, for which string theory is developed. This thing called Maldacena duality [wikipedia.org] and state that c

  • by Chuckstar (799005) on Tuesday April 14, 2009 @08:18PM (#27580921)

    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.

  • by serutan (259622) <snoopdoug.geekazon@com> on Tuesday April 14, 2009 @10:27PM (#27581919) Homepage

    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?

  • Perfect Holographic Liquid...Auuugghhh...

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