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Exploring Superstrings in the Lab

Posted by Zonk on from the knitting-a-scarf dept.

ultracool writes "Physicists at Utrecht University in the Netherlands have come up with a way of observing a superstring by utilizing Bose-Einstein condensation (BEC). A one-dimensional BEC in an optical lattice is rapidly rotated, causing a quantized vortex to form. The bosonic part of the superstring consists of this vortex line. Inside the vortex, they would trap an ultracold cloud of fermionic atoms. Hopefully this will allow observation of the supersymmetry between bosons and fermions, thus providing the first experimental evidence to support superstring theory."

11 of 312 comments (clear)

  1. Woah.. by Anonymous Coward · · Score: 5, Funny

    I almost understood a word of that.. Almost.

  2. I use super-strings all the time by Anonymous Coward · · Score: 5, Funny

    http://java.sun.com/j2se/1.5.0/docs/api/java/lang/ StringBuilder.html .
    They're great. You can modify them and they aren't synchronized so they're fast, too. If these scientists are only just now discovering them they should try reading some newsgroups.

  3. More info... by KeiserSoze · · Score: 5, Informative

    A more detailed explanation of http://en.wikipedia.org/wiki/Superstringssuperstri ngs.

  4. It might not hurt... by daveschroeder · · Score: 5, Informative

    ...to refer people to more information on Bose-Einstein condensates (BEC):

    BEC wikipedia page
    BEC home page at Colorado
    BEC at NIST
    What is a BEC?

  5. Supersymmetry != string theory by n0mad6 · · Score: 5, Insightful
    I am not a condensed matter physicist (I'm a high-energy physicist), but it seems like this is a way to demonstrate a supersymmetry (a symmetry between fermions and bosons) rather than a demonstration of a string theory. In experimental high-energy physics, its widely believed that supersymmetry will be proven or disproven conclusively within the next decade. String theory is an entirely different matter.

    Any string theorists out there want to chime in?

    1. Re:Supersymmetry != string theory by Stalyn · · Score: 5, Informative

      Witten said that proving supersymmetry would be helpful in understanding string theory. From what I understand supersymmetry down the road implies string theory. So if supersymmetry is disproved by implication so is string theory. However if supersymmetry is proved is does not prove string theory. But rather add towards understanding and maybe later proving string theory.

      but IANAST.

      --
      The best education consists in immunizing people against systematic attempts at education. - Paul Feyerabend
    2. Re:Supersymmetry != string theory by Anonymous Coward · · Score: 5, Informative

      I'm also not a string theorist, but I believe that (string theory) + (supersymmetry) = (superstrings). This seems to be an attempt to construct a condensed matter analog of the superstring theory that could underly particle physics. In other words, it's an analog that doesn't necessarily mean that superstrings are or are not the underlying fundamental theory of physics.

    3. Re:Supersymmetry != string theory by epine · · Score: 5, Insightful


      Dude, proof only exists within closed formal systems. The universe does not come with an end-user-license promising that any observation *ever* can be repeated, e.g. that the sun comes up tomorrow, or that protons don't decay into Mars Bars.

      What we've learned about the universe is that physical observation is highly (some say unrealistically) compressible. We write down a small set of rules (quantum electrodynamics is the best example) and then we find that trillions of physical measurements taken from just about any situation we can think up are *consistent* with the small set of rules we've written down. This doesn't mean the set of rules we've written down it the smallest set of rules consistent with the universe. With each "unification" (e.g. electricity with magnetism) the set of rules becomes more compact relative to how much of the universe it consistently describes. It's important to note that we usually know ahead of time that our system of rules can't possibly be consistent with everything (general relatively and quantum mechanics are inconsistent in their present forms). From the point of view of proof, we knew from the outset that both of these theories are false. Yet each of these theories describes an incredible range of phenomena, and for the most part, the two theories don't much overlap in what they describe. If they did overlap more, it would be far easier to concoct experiments to resolve the known inconsistencies.

      I'm quite depressed at how few people are familiar with the work of Kolmogorov and Chaitin. Most physicists fail to fully appreciate these results. The bottom line is that algorithmic compressibility is all we've got, and truth itself is a gossamer filigree we can at best approximate.

  6. Re:I suppose it makes sense to physicists by Dr.+Weird · · Score: 5, Informative
    If some object is made up of an even number of fermions, it is a boson, otherwise it is a fermion (the neutrons and protons that make up the nuclei of the atom are each fermions, as are the electrons surrounding it).

    Now, for the reason: if you know some quantum physics, think of taking two composite objects and interchanging them; fermions wavefunctions change sign under this interchange. For the composite object, its wavefunction looks like (an anti-symmetrized) product of single-particle wavefunctions. If those are fermionic and there are an odd number of them in the composite wave function, interchanging the two composite wavefunctions will produce an odd number of sign changes in the product, for an overlal sign change. If there are instead an even number of fermionic single-particle wavefunctions in the composite wavefunction, the resulting even number of sign changes under interchange produces no net sign change in the many-body wavefunction.

    This is easily extended to composite objects that are a composite of both bosons and fermions.

  7. MOD PARENT UP! by Dr.+Weird · · Score: 5, Interesting
    This is an important point that I think the article really butchers: as far as I can tell (and I am a condensed matter physicist), they are *NOT* actually creating fundamental superstrings, i.e. those predicted by string theory. Rather, they are creating objects in BEC's that behave in exactly the same way as predicted by that theory.

    To use a computational analogy, they are simulating the equations of string theory using a BEC as the computer. So whatever results they get had better agree with string theory! They aren't actually testing whether these explain the world, just exploring the equations of string theory with an efficient computer -- the BEC.

  8. Ummm... Reality check. by volsung · · Score: 5, Informative
    Not to rain on anyone's parade, but based on that article, this is NOT a test of supersymmetry or string theory in the sense the article blurb leads you to believe. (Surprised?) These physicists have thought up a clever way to create an analog to a superstring out of a macroscopic quantum system. The neat thing about condensed matter physics is that you can concoct systems that behave like more fundamental systems which you can't easily create. You can then test the implications of a particular mathematical model.

    So this is very cool (literally!) science, but NOT a test of superstring theory as a way to describe fundamental particles or interactions. At best, it will provide some interesting checks of the mathematical predictions of string-like theories, but only translated into this system. You still won't know if string theory has any hope of describing real electrons, photons, gravitons, etc.