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New Calculations May Lead To a Test For String Theory 284

Posted by timothy
from the string-washing-powder-what's-the-difference dept.
dexmachina writes "A team of theoreticians, led by a group from Imperial College London, has released calculations that show string theory makes specific, testable predictions about the behaviour of quantum entangled particles. Professor Mike Duff, lead author of the study from the Department of Theoretical Physics at Imperial College London, commented, 'This will not be proof that string theory is the right "theory of everything" that is being sought by cosmologists and particle physicists. However, it will be very important to theoreticians because it will demonstrate whether or not string theory works, even if its application is in an unexpected and unrelated area of physics.' In other words, string theory may finally have shed its critics' most common complaint: unfalsifiability. However, given the second most common complaint, I can't help but wonder: which string theory?" Update: 09/03 23:34 GMT by S : Columbia University's Peter Woit, author of the Not Even Wrong blog, says these claims are overblown, and adds that a number of string theorists said as much to Wired.
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New Calculations May Lead To a Test For String Theory

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  • Well... (Score:5, Funny)

    by Korbinus (589005) on Friday September 03, 2010 @05:32AM (#33462576) Homepage Journal
    That's a good news for Dr. Leonard Leakey Hofstadter...
  • Oops (Score:5, Informative)

    by dexmachina (1341273) on Friday September 03, 2010 @05:44AM (#33462612)
    It seems I may have jumped the gun [columbia.edu] on this one. My bad for being such an easy mark of sensationalist pop science headlines.
    • It's gonna be so cool if it says "wrong!"

    • Re:Oops (Score:5, Interesting)

      by maxwell demon (590494) on Friday September 03, 2010 @09:06AM (#33463562) Journal

      Indeed, it's worse. While I don't know much about string theory, I do work in the field of entanglement. And there's no way you could experimentally test this classification, for the simple reason that it's a classification. It may be a more or less useful classification, but you cannot experimentally test whether a classification is right (apart from that an reasonable entanglement classification has to be SLOCC invariant, which this classification is, but of course the others are as well). Trying to experimentally test if a classification is right is like doing an experiment on whether classifying a fruit on its color or on its size is more correct. What you can do is to evaluate the usefulness of a classification (i.e. does it tell you something interesting about the state, like what you can do with it; in the fruit example, you might find that classifying fruits on nutrition value may generally be more useful than classifying on water content).

    • by eldavojohn (898314) * <eldavojohn&gmail,com> on Friday September 03, 2010 @09:13AM (#33463618) Journal

      It seems I may have jumped the gun [columbia.edu] on this one. My bad for being such an easy mark of sensationalist pop science headlines.

      Don't feel bad, I submitted it a day before you did [slashdot.org]. What really blows my mind is that Not Even Wrong used my submission as evidence that Slashdot was running a story on it:

      Update: No press campaign for a “finally string theory is testable” claim is complete without a Slashdot story

      Big news for theoretical physicists who are fed up with the inability to test String Theory

      (that's from my submission)

    • Re: (Score:3, Interesting)

      by iris-n (1276146)

      I don't think I can blame your for not reading the paper. They just lied and lied and lied in the press release: "Researchers describe how to carry out the first experimental test of string theory"

      Come on! I know that press releases are about PR not science but they should at least bear any relation to the paper.

      Look in the paper [arxiv.org]. The word experiment only appears once, and they don't claim to describe an experiment; not even that it is possible or conclusive.

      That said, the question is: who is the lier? The

  • But.. (Score:3, Insightful)

    by Entropy98 (1340659) on Friday September 03, 2010 @06:00AM (#33462680) Homepage

    However, given the second most common complaint, I can't help but wonder: which string theory?
     
    Exactly, if this turns out to be false it won't disprove all string theory.
     
    --
      windows media codec pack [cnet.com]

    • by hedwards (940851)
      But if they accept that it disproves that theory, then they may get a boost in credibility. From being incompetent liars to being merely wrong. Which for string theorists would be a substantial step up in terms of actual credibility.
  • Not a test (Score:5, Insightful)

    by UnHolier than ever (803328) <unholy_@ho[ ]il.com ['tma' in gap]> on Friday September 03, 2010 @06:04AM (#33462704)
    I scanned through the article and from what I see, they have made an equivalence between the maths used in string theory and the maths used in entanglement. This is interesting in itself, because this allowed them to port a result from string theory to entanglement theory, a result which was not known before and could be falsified.

    However, this is like saying that the mathematical theory used to count apples harvested from an orchard (addition of natural numbers) is the same as the mathematical theory behind the algorithm the slashcode uses to count the number of comments below threshold (addition of natural numbers). It allows one to port result from ancient mathematics to modern applications without having to rederive everything from first principles; it does not mean that sub-threshold comments are, deep down, really made of apples.
    • it does not mean that sub-threshold comments are, deep down, really made of apples.

      Youtube comments would be oranges.

    • However, this is like saying that the mathematical theory used to count apples harvested from an orchard (addition of natural numbers) is the same as the mathematical theory behind the algorithm the slashcode uses to count the number of comments below threshold (addition of natural numbers). It allows one to port result from ancient mathematics to modern applications without having to rederive everything from first principles; it does not mean that sub-threshold comments are, deep down, really made of apple

  • Physicist speaking (Score:5, Informative)

    by JohnFluxx (413620) on Friday September 03, 2010 @06:12AM (#33462732)

    As a physicist, I do get a bit annoyed at the constant attacks on string theory in public media.

    Let me just state a few points please:

      * We have Quantum Mechanics for the realm of the very small
      * We have General Relativity for the realm of the very heavy
      * Both of these theories fit observational data and work very well
      * The two theories contradict each other in the case of very heavy and very small object (e.g. tiny black holes)

    So, we need a new theory that gives the same predictions at QM and GR in the realms that we can measure them. This is where string theory etc comes in. But we do not yet have experimental data for very heavy and very small objects. If you want to complain about string theory not being testable, then accept that your same complaint is going to apply to EVERY grand-unified-theory that we know of.

    Conclusion
    =========

    If you complain at string theory, then PLEASE state what you are proposing. What is the use in complaining when you have no alternative? The main scientific proponents against String Theory also just happen to have their own pet theories (e.g Quantum Loop Gravity) which are in an even worse situation.

    If you complain about string theory taking so long, then what do you expect? It has taken 16 years just to do a single experiment (The LHC).

    The only way we can make String Theory etc testable is by further research. If you dislike, please propose a better solution rather than just complaining.

    TL;DR - People complain at string without proposing anything better.

    • by PolygamousRanchKid (1290638) on Friday September 03, 2010 @06:29AM (#33462798)

      If you dislike, please propose a better solution rather than just complaining.

      It's turtles . . . all the way down . . .

      • by fyngyrz (762201) on Friday September 03, 2010 @07:49AM (#33463094) Homepage Journal

        No, it's nylons... and they only go down from the thigh (otherwise we're talking about pantyhose, which are a creation of the devil.) From the thigh up, it's garters. If you find turtles, retreat immediately. It's likely to get worse, and you don't want to know about that... guys that want to know about that become gynecologists. And no one with any sense at all wants to encounter dark matter. Also, garters first, panties (optional, of course), second.

        Experimenting in this realm is highly recommended. Repeat a lot - you want to be sure.

      • by Sulphur (1548251)

        There are only three Ninja Turtles.

    • Re: (Score:2, Interesting)

      So wait, we have two theories that describe different realms and no data for the intersection of the two realms, but people are trying to come up with a theory for the intersection?

      That's like saying, I know how to fly a plane, and I know how to drive a car, but neither skill applies to flying cars, which I've also never seen.

      But they must exist, right??

      • by Nerdfest (867930) on Friday September 03, 2010 @07:30AM (#33463008)
        Did you just use a car analogy in an article about testing string theory?
      • by MartinSchou (1360093) on Friday September 03, 2010 @08:12AM (#33463198)

        So wait, we have two theories that describe different realms and no data for the intersection of the two realms, but people are trying to come up with a theory for the intersection?

        We know that very very small objects exists (subatomic particles). We also know that very very massive objects exists (stars).

        Usually the two are linear. The smaller an objects, the less mass it has.

        Unfortunately there IS a crossover point. There are objects with a density of approximately 370,000,000,000,000,000 kg/m^3. These can be modeled with regular physics for 'large' objects, and they affect things far outside the realm of Quantum Theory (i.e. you can orbit a human around such an object). Get too much above this point though, and you end up with an object that seems to be smaller than the smallest subatomic particles (Quantum Theory) yet affects things that are far outside the realm of Quantum Theory - these items are commonly known as black holes.

        How do they work? Well ... they're insanely massive. And they're really tiny. As to what goes on inside them ... we've no clue. We can't use Quantum Theory because it's too massive, and we can't use regular physics, because it's too small.

        • by tenco (773732)

          How do they work? Well ... they're insanely massive. And they're really tiny. As to what goes on inside them ... we've no clue. We can't use Quantum Theory because it's too massive, and we can't use regular physics, because it's too small.

          How do you know they are tiny? Sure, GRT predicts a singularity. But has anyone ever actually measured the size of a black hole's mass distribution beyond the event horizon?

        • >you end up with an object that seems to be smaller than the smallest subatomic particles

          I think the important word here is "seems". Black holes were discovered when Schwarzchild found a way to get 1/0 in Einstein's field equations.

          From then, it's been 95 years of madness perpetuated by people who have never seen a "limit" drawn on a graph.

      • So wait, we have two theories that describe different realms and no data for the intersection of the two realms, but people are trying to come up with a theory for the intersection?

        Um, the cross-over objects exist. Grandparent poster is wrong, you don't need small black holes; any singularity has the problem of needing quantum mechanics and general relativity to describe it. This is true of the inner workings of any black hole, for example. (No, we can't get data from one, as far as we know.) Or, just fer instance, the Big Bang. There is a surprising amount of interest in modeling that one.

        Does that make more sense?

      • Re: (Score:2, Interesting)

        by radtea (464814)

        So wait, we have two theories that describe different realms and no data for the intersection of the two realms, but people are trying to come up with a theory for the intersection?

        We have two theories that describe different realms (although not the realms mentioned in the summary) and we have a known isomorphism between the mathatical description of one of them in stringy terms and the behaviour of the other. This paper extends that isomorphism into a currently intractable area.

        So it's more like saying you know that people who can drive Fords can also drive Toyotas, but Toyota has just come out with a new model that none of the Toyota drivers can handle, so why not give it to a For

    • by Mikkeles (698461)

      Since I have a physicist here :^)

      Since string theory cannot be distinguished from , e.g., QM (i.e., string theory is untestable), does that not also imply that QM cannot be distinguished from string theory (i.e., QM is untestable)? So why is QM given precedence?

    • by Capt'n Hector (650760) on Friday September 03, 2010 @06:52AM (#33462872)
      I think the public media attacks string theory on the grounds of its impossibility to test because they don't know any better. Those of us in physics and math have very real and strong arguments against string theory that have little to do with testing.
    • by Sycraft-fu (314770) on Friday September 03, 2010 @06:56AM (#33462894)

      Is that it isn't. What I mean by that is it doesn't seem to make any testable predictions. At this point, it is just a bunch of math wanking. Now there's nothing wrong with purse math. A lot of useful theories start out that way and I like the Bacon quote "If in other sciences we should arrive at certainty without doubt and truth without error, it behooves us to place the foundations of knowledge in mathematics."

      However when all you've got is a bunch of neat math with no real testable predictions, it is not a theory and it is not the sort of thing to be crowing about to the general public. XKCD, as usual, did a humorous job summing it up: http://xkcd.com/171/ [xkcd.com].

      If you are going to complain that people complain about the lack of testability then you need to do two things:

      1) Read The Logic of Scientific Discovery again and brush up on what a theory is and isn't.

      2) Don't go making press releases. I'm not saying you personally have done this but physicists are awful happy to talk to the press about something they can't prove.

      Part of it is simply wanting accuracy in the use of the words because let's face it: In science accuracy matters. Being pedantic about terms is important in science. Another part of it is this is the kind of thing that confuses normal people. With evolution, scientists have gone to a lot of trouble to explain that a theory is NOT a guess, NOT a wild idea, etc. They show other theories and how they work, how many things we accept as true are theories.

      Well something like this undermines that to an extent, because here is something being called a theory that is not only untested, but that they can't even figure out how to test. It is the kind of thing that can make people say "But wait, if this is a theory then theory doesn't mean what you said."

      • ...then let's not throw around phrases like "theories accepted as truth."

        A much better way to construct such a remark is "theories we presently have (very|extremely|) high confidence in."

        Because I gotta tell ya, "truth" is one of those nasty words, like "belief", that usually - outside of logic and math, where it means something else - means someone is glossing over something, and it's probably not insignificant.

        Just saying. You want a way to write about worldviews - including scientific ones - that

        • I'm speaking of regular individuals. Yes I understand that when you get down to it, nothing outside math can be prove true as in no room for anything to dispute it ever (and of course just because something is true in math doesn't mean it applies in the world, could all just be in our heads). However normal people accept things as true, and they accept much of science as true. So truth is a useful thing to talk about.

        • Wow I hope this is a troll for your own sanity. Use ctrl+F on "truth" and see your epic fail.

      • I guess I'm currently in the 'so what' camp. If a String Theory covers all of QM, Relativity, and Gravity, and it makes useful predictions that can be tested and leads to further knowledge and useful engineering - I guess I don't really care if the underlying assumptions are right or not.

        By all means, keep working on something better, but if the above is true, it's a good theory to work with. We got quite a bit of useful work done with Newtonian physics, and QM/QED have gotten us much further, even if the

    • by Anonymous Coward on Friday September 03, 2010 @07:07AM (#33462932)

      If you complain at string theory, then PLEASE state what you are proposing. What is the use in complaining when you have no alternative?

      Which by an astonishing coincidence is the same argument in favor of god-did-it theory.

      • Re: (Score:3, Informative)

        by JohnFluxx (413620)

        I know you are joking, but I did mean:

        "Please state what you are proposing that scientists should do instead of researching such theories"

        rather than

        "If you can't give an alternative theory then string theory must be true"

    • Re: (Score:3, Insightful)

      by CheshireCatCO (185193)

      So, we need a new theory that gives the same predictions at QM and GR in the realms that we can measure them. This is where string theory etc comes in.

      Not really. Last I checked, String Theory hasn't made any useful predictions about systems like this. No one has managed to fold gravity into a Theory of Everything yet, unless I missed an important update. (Feel free to correct me if I have.)

      TL;DR - People complain at string without proposing anything better.

      A theory that offers no new powers of explanation and prediction is itself no better than the pre-existing paradigms. Until String Theory can show itself to have some value (leaving aside the issue of whether it's the best such model), there's no reason to cling to

    • by Moraelin (679338) on Friday September 03, 2010 @07:37AM (#33463048) Journal

      Actually, it seems to me like we don't call those grand-unified things a proper scientific theory either. As long as there are no testable predictions, and it fails Occam's Razor, it's not a theory, plain and simple. It's a hypothesis.

      Yes, there is a name for a theory which hasn't yet been tested: hypothesis.

      And really, as someone who's gotten tired of hearing Young Earth Creationists go "well, evolution is just a theory" and having to explain to them "yeah, but theory in science doesn't mean what you think. It means it already made testable predictions and is the best we have"... it's getting annoying to see that a whole bunch of physicists are actually using it exactly as the YECs and conspiracy theorists think: as just an untested and untestable supposition, which may or may not actually hold any water at all.

      Yes, I realize that calling it a "theory" is more science-y sounding and good for your funding. But it devalues the whole idea of science for everyone. If we accept that some untested and untestable calculation is just as worthy of being called a "theory" with a straight face as GR or electromagnetism just because it's the pet supposition of some physicist, then basically why wouldn't Behe's pencils-up-the-nose ID idiocies be a "theory" too? I mean Behe _is_ a professor of biochemistry.

      Call it the String Hypothesis, and you'd see a lot less complaints, basically.

      • Yes, there is a name for a theory which hasn't yet been tested: hypothesis.

        A hypothesis is the starting point. A theory is the hypothesis and everything which follows from it. The hypothesis can be true or false, a theory can also be true or false.

      • Re: (Score:2, Insightful)

        As long as there are no testable predictions, and it fails Occam's Razor, it's not a theory, plain and simple.

        I hate Contact, I hate Contact, I hate Contact.

        Because Carl Sagan had a misunderstanding about what Occam's Razor is, but nevertheless explained it wrongly in Contact, now millions of people have been introduced to the concept as explained by his novel or the movie. "The simplest explanation is usually the correct one" is not Occam's Razor. Occam's Razor says nothing about correctness at all, and it's most certainly not a requirement to create a scientific theory. All it actually says is that if two theo

        • Chill out, Pinky (Score:5, Insightful)

          by Moraelin (679338) on Friday September 03, 2010 @10:26AM (#33464342) Journal

          Chill out, Pinky.

          Where did I say I was using the one from Contact or anything. Yes, I'm using largely the version you explain there: as long as two hypotheses explain the exact same sets of measured data, go with the less complex one, leave the more complex one for when you actually have some data that the other one can't explain.

          In exactly that sense, as long as the String Hypothesis doesn't have at least one testable prediction [b]of its own[/b], that can't be explained by the simpler GR and QM, it freaking fails Occam's Razor.

          It doesn't mean it's _false_ and nowhere did I say it's _false_. I said until such time as it makes testable predictions of its own, it's just a _hypothesis_. Different thing from "false".

          So basically, what, you made all that fuss to answer to your own strawman?

    • TL;DR - People complain at string without proposing anything better.

      What ever happened to "we don't know"?

      You can criticize a theory without proposing anything better if you don't have a theory yourself - because you can point to flaws in the other theory. Observations that seem to go against the theory, the impossibility of falsifying the theory, etc.

      For example, I can point at "intelligent design" and say it's a bad theory because it is not falsifiable and I don't have to offer an alternative theory of ab

      • Forgive the self reply - I wanted to amplify:

        Saying "don't criticize a theory unless you have a better one" is actually counter productive because it encourages the championing of pet theories rather than the actual doing of science.

    • If you want to complain about string theory not being testable, then accept that your same complaint is going to apply to EVERY grand-unified-theory that we know of.

      And why do you think this would be a problem? My complaint about the Christian god not being testable does also apply to other deities, but the Christians are the ones pissing in my back yard, so those are the ones I complain about. Similar with the string faith.

      If you complain at string theory, then PLEASE state what you are proposing.

      That's

    • by syousef (465911)

      >If you complain at string theory, then PLEASE state what you are proposing.

      Turtles all the way down! Everybody knows that!

    • by plumby (179557)

      If you complain at string theory, then PLEASE state what you are proposing.

      I never get this line of argument. Surely if you've got evidence that demonstrates a particular theory is clearly wrong, it's better to flag that up even if you've not got any specific alternative. If nothing else, it should encourage others to stop wasting their time pursuing something that's clearly wrong.

      I'm not saying that string theory is wrong (I'm not a theoretical physicist, and I've got no particular views on this theory), b

    • by radtea (464814)

      People complain at string without proposing anything better.

      Not so. There are a variety of more-or-less heuristic alternatives to string theory, they just don't have supporters that are quite so grandiose and arrogant as string theorists.

      The problem with string theory is that it is uniquely hard to build models of low-energy systems using any of its variants, which is funny because it has been applied in pure form to various solid-state systems. But due to extremely high string tension (or equivalent parameter) that is necessary in the "theory of everything" strin

    • String theory poses to the general public as what modern physics is. Take a look at the books available at a bookstore, science articles at the gernal press, etc. All you'll see is bold predictions about how our universe fist within a multiverse, how string theory explains the inner workings of a black hole, and so on. There is nothing wrong with you working on string theory, your PR department just needs to stop presenting it as a certainty.

    • by hedwards (940851)
      You know what, just for that, from now on I'm going to call it "String Hypotheses" until such a time as somebody actually successfully falsifies something. And then comes up with a test that seems to work. It doesn't matter whether anybody has anything better to go on, the fact is that until they start to falsify things when they fail, it isn't science, it's a weird religious fetish for atheists.
    • by Dhalka226 (559740)

      If you complain at string theory, then PLEASE state what you are proposing. What is the use in complaining when you have no alternative?

      As I read your post, and especially this part, I was struck by how wrong I consider this sentiment.

      Science is about the search for answers, the search for truth, and we have spent the better part of our history refining what we think to be important in that search. "I don't know what the answer is, but that is wrong" is and should always be a perfectly valid answer.

      Th

  • by jamesh (87723) on Friday September 03, 2010 @06:20AM (#33462774)

    which string theory?

    The one that will come out of the renormalization that they'll need to do to make it fit the observed outcome of this experiment, obviously.

  • by ortholattice (175065) on Friday September 03, 2010 @07:44AM (#33463074)
    is here: http://arxiv.org/abs/1005.4915 [arxiv.org].
  • Rediculous. (Score:4, Funny)

    by AntEater (16627) on Friday September 03, 2010 @08:20AM (#33463252) Homepage

    This has been solved for quite a long time. Perl's built in regular expression tests have had the ability to check for strings for many years now.

    if( $var =~ /\w/) {}

  • While we are trying to use maths to solve pretty much everything, maybe the thing that is flawed is our numbering system?!?

    Remember the roman numbers? It was supposed to be the most logical thing in the world back then. Then we came up with base 10 / positional numbering system. All of a sudden, everything was simpler, everything was easier to calculate, and it opened up our eyes on a lot of things.

    But then, maybe we reached the end of what our numbering system / way of thinking about maths, can do.

    Ju
    • Your poster tells that you aren't good on math or physics. Just as an example, QM doesn't rely on 'our nunbering system', almost all calculations are made on a Hilbert space, based on the Dirac delta function. There are no numbers as you know them there. Ok, sometimes a real nunber pops from a calculation, but that is normaly just after all the heavy stuff.

      Every physics theory uses a different 'numbering system'.

    • While we are trying to use maths to solve pretty much everything, maybe the thing that is flawed is our numbering system?!?

      Hear, hear!

      From now on I propose the following for the new numbering system:

      1. Thou shall count to three, no more, no less. Three shall be the number thou shalt count, and the number of the counting shall be three.

      2. Four shalt thou not count, neither count thou two, excepting that thou then proceed to three. Five is right out.

      3. The largest number is 45,000,000,000.

    • by hedwards (940851)
      Actually it's pretty solid, the only thing in the last 200 years or so that it's really screwed it up was when somebody disproved the fifth postulate [wikipedia.org]. Which is to say that it wasn't the numbers that were the problem it was the presumptions we were making about reality which were. And right after the work to disprove it was completed all kinds of really amazing discoveries were made. There's still a lot of things like that out there to do, the biggest one is that there's a tendency to assume that because it
    • The thing is, decimal didn't make everything simpler and easier to calculate and open up our eyes. It feels that way, because you've spent you're whole life using it and everything else feels weird and foreign. Base 10 feels natural because we have 10 fingers and 10 toes (among other reasons).

      But you can see the evidence of our history of using base 12 from our words for numbers (this is the reason eleven and twelve aren't firsteen and seconteen). Base 12 is also very natural because it has so many factors

  • The second most complaint I have with String Theory is how ordinary people can possibly understand the mathematics. I can just about grasp Einstein, Tensors and so forth. Multidimensional manifold's, M-theory and the like leave me feeling intellectually inadequate. Is it all just some obscurantist joke, or is reality really that complicated?
    • Well, I'm just a layman too, but I rely on the word of some math specialists, that confirmed that it indeed is that hard. Anyway, there is no requirement on the scientific method that your theory must be understandable by lay people, or even by specialists of the area, it must be as complex as the data requires.

  • Err, in the suggested articles on TFA there is this link Theoretical Physicists Develop Test For String Theory [sciencedaily.com] From Jan. 25, 2007.

    Did they just call bullshit on themselves?

  • Wazza? (Score:4, Insightful)

    by ErikZ (55491) * on Friday September 03, 2010 @09:17AM (#33463642)

    In other words, string theory may finally have shed its critics' most common complaint: unfalsifiability.

    It's critics? It's CRITICS.

    Holy crap man. After spending a significant chunk of your life working on string theory, wouldn't you want to test it? That's part of the whole "I'm a scientist"!

    • Re: (Score:3, Funny)

      by ceoyoyo (59147)

      My head hurts. You took the correct phrase in the summary "its (plural) crtics' (plural possessive)" and turned it into the mind bending "it's (contraction - it is) critics (plural)". Twice. With bold face.

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