Want to read Slashdot from your mobile device? Point it at m.slashdot.org and keep reading!


Forgot your password?
Math Science

Physicists Say Graphene Could Create Mass 184

eldavojohn writes "Graphene has gotten a lot of press lately. The Nobel prize-winning, fastest-spinning, nanobubble-enhanced silicon replacement is theorized to have a new, more outlandish property. As reported by Technology Review's Physics Blog, graphene should be able to create mass inside properly formed nanotubes. According to Abdulaziz Alhaidari's calculations, if one were to roll up graphene into a nanotube, this could compactifiy dimensions (from the sheet's two down to the tube's one), and thus 'the massless equations that describe the behavior of electrons and holes will change to include a term for mass. In effect, compactifying dimensions creates mass.' What once would require a massive high-energy particle accelerator can now be tested with carbon, electricity, and wires, according to the recent paper."
This discussion has been archived. No new comments can be posted.

Physicists Say Graphene Could Create Mass

Comments Filter:
  • by somersault ( 912633 ) on Friday October 22, 2010 @12:56PM (#33986942) Homepage Journal

    Scientists have now isolated the particle that causes this strange mass inducing effect, and have dubbed it the "YoMamma".

  • What once would require a massive high-energy particle accelerator can now be tested with carbon, electricity, and wires, according to the recent paper."

    Out of the garage, into the lab, back to the garage. Bill Nye must be so proud :)

    • by mcgrew ( 92797 ) * on Friday October 22, 2010 @01:54PM (#33987862) Homepage Journal

      The link to the paper just gives the executive summary, which actually conveys little information. Even wikipedia wasn't much help. If there's a physicist out there, I get the impression that somehow leptons are being converted to fermions? If so, how, and why do they? If not, could someone give a good explanation?

      This is fascinating, but I can't find much explanation.

      http://www.ncbi.nlm.nih.gov/pubmed/17358966 [nih.gov]
      Magnetic confinement of massless Dirac fermions in graphene.
      De Martino A, Dell'Anna L, Egger R.

      Institut für Theoretische Physik, Heinrich-Heine-Universität, D-40225 Düsseldorf, Germany.

      Because of Klein tunneling, electrostatic potentials are unable to confine Dirac electrons. We show that it is possible to confine massless Dirac fermions in a monolayer graphene sheet by inhomogeneous magnetic fields. This allows one to design mesoscopic structures in graphene by magnetic barriers, e.g., quantum dots or quantum point contacts.

      PMID: 17358966 [PubMed]

      • by idontgno ( 624372 ) on Friday October 22, 2010 @02:01PM (#33987966) Journal

        If there's a physicist out there, I get the impression that somehow leptons are being converted to fermions?

        When life hands you leptons, make leptonaide.

        Indeed, I'm not a physicist. How'd you guess?

      • by kurokame ( 1764228 ) on Friday October 22, 2010 @02:08PM (#33988066)

        Actually, the abstract nails what the actual news here is.

        You can't confine a Dirac electron electrostatically. They show that it can be done with magnetic fields. This is sort of cool because it has potential ramifications for incorporating nanotechnology into electronics.

        After the wharrgarbl, it mutates into a headline about creating mass and using it to power FTL starships from video games.

      • Something Fishy (Score:5, Informative)

        by Roger W Moore ( 538166 ) on Friday October 22, 2010 @03:15PM (#33989052) Journal

        If there's a physicist out there, I get the impression that somehow leptons are being converted to fermions?

        Leptons (e..g electron) are fermions. However there is something very fishy with this paper. For example 10^6 m/s is not relativistic. If you calculate the gamma factor (gamma=1 is what Newtonian physics assumes) you get 1.0000056. This means they are very non-relativistic and Schrodinger should work fine for them unless there is some subtle effect at play. Indeed to give electrons this energy you need to accelerate them through a potential of 2.8 volts so rather than needed a particle accelerator any one with a vacuum pump, a vacuum-tight container, some wire and two AA batteries can experience the fun of "relativistic" electrons.

        What I suspect is happening is that the conditions on graphene have altered the electron behaviour so, rather than test anything fundamental, you are testing the properties of electrons on graphene. You cannot do real relativistic physics with this because if you get an unexpected result you have no idea whether it is because there is some new, unexpected physics at work or whether your approximation of the environment is simply wrong and you need to use a different model for it. Hence, while interesting, this is not the way to do real, relativistic physics: for that you need something that is truly relativistic, not just something which might, under certain conditions, act like something relativistic.

      • I get the impression that somehow leptons are being converted to fermions?

        I'm not a physicist, but it is my understanding that leptons are fermions. The two main groups are fermions (take up space, more or less) and bosons (don't take up space). Fermions further break down into two groups, hadrons (quarks) and leptons (electrons, muons, tauons, and neutrinos).

  • Is this just a math trick, or what is going on here? I'm pretty sure "we're creating mass" is not literally what's happening, but I can't make heads or tails of it.
    • by bsDaemon ( 87307 ) on Friday October 22, 2010 @01:02PM (#33987052)

      I think they're just claiming the mass they expect to make next year, assuming they'll balance their mass sheets at that point?

      • Re: (Score:3, Funny)

        Yes, they're actually losing a little mass on each transaction, but they're buying "observations". They'll make is up on volume!
    • Yep. It's a math trick at this point. What's interesting is that even having a mass term in the equations implies that we COULD create mass, if we supply the proper conditions (like adding lots of energy at one end of the tube).

      Or at least, that's my guess. TFA is an abstract that I'm barely understanding, and the linked paper is way over my head.

      • by Lobachevsky ( 465666 ) on Friday October 22, 2010 @01:32PM (#33987516)

        All science predictions are math tricks. If the prediction holds up, our existing models are correct, otherwise, our existing models are broken. Creating mass from graphene is not a new theory, it is the _consequence_ of our existing theories that someone cleverly derived.

        Point is, either way, Abdulaziz Alhaidari is now famous and has done the incredible. He's either famous for making a marvelous derivation of our existing theories, or he's famous for disproving our current models by explaining what our current models predict that would later be experimentally contradicted. Just as the Manhattan project was a test of atomic theory; if it worked, an amazing weapon was created; if it didn't work, it had profound ramifications on invalidating the the atomic theory of the day. Either it's a win for engineering, building something amazing, or a win for science, changing the models to more closely match reality.

        • by icebike ( 68054 )

          Or he will become famous like Fleischmann and Pons [wikipedia.org].

          Just sayin.....

        • by blair1q ( 305137 )


          [X] He's a blithering crackpot.

      • Create mass via lots of energy.


        • Re: (Score:3, Funny)

          by mcgrew ( 92797 ) *

          No, more like a Catholic priest. They create mass from hot air, holy water, some wine and a cracker, don't they?

          Physics can't do that!

      • Itth not a math trick, itth a *mathth* trick.

    • the best awnser I could come with is : We dont know yet:

      There are some important mathematical differences between the mass that can be generated this way and the stuff you can rap your knuckles on. But now physicists have the chance to compare the effects in an ordinary lab.

    • by hcg50a ( 690062 ) on Friday October 22, 2010 @01:09PM (#33987158) Journal

      The /. title of this article is wrong, stupid and misleading.

      The title of TFA is "Dynamical mass generation via space compactification in graphene", which is mostly incomprehensible.

      The abstract sez "Fermions in a graphene sheet behave like massless particles. We show that by folding the sheet into a tube they acquire non-zero effective mass as they move along the tube axis. That is, changing the space topology of graphene from 2D to 1D (space compactification) changes the 2D massless problem into an effective massive 1D problem."

      A plain english annotated translation is "Electrons in a graphene sheet behave like massless particles. We show that by folding the sheet into a tube they behave like massive particles as they move along the tube axis. That is, changing the shape of graphene from 2D to 1D changes the 2D massless problem into an effective 1D massive problem, which may be easier to solve or model or understand in certain respects.

      Note electrons have the same real mass in both cases. Mass is not being created or destroyed.

      • "Physicists say" - the ultimate idiot switch activator.
      • by Nimey ( 114278 )

        kdawson posted it, but I wonder if that's his fault or eldavojohn's.

        edj, I know you read regularly, so what do you have to say?

        • Re: (Score:3, Insightful)

          by blair1q ( 305137 )

          People (i.e., mostly you) seem to blame kdawson, but really, he's just clicking the button when the post bubbles to the top of the Firehose, which happens because the Firehose is an idiocracy. People voting there are mostly ignorant, so anything that is above their understanding gets a positive nod, because most things that reach the front page are above their understanding, so they think that's the criterion.

          Sometimes, not voting is better for you than voting is. Like, when you're too uninformed or misin

      • by geekoid ( 135745 )

        It's only incomprehensible ifm yuo don't know what compactification is.

        • by blair1q ( 305137 )

          Is it related to strategery, refudiation, and misunderestimating?

          • No, “compactification” is actually a word, albeit an uncommonly used word... “compactify” and “compactifying”, on the other hand, are not (“compact” and “compacting” are the words that the summary writer should have used).

      • Re: (Score:2, Informative)

        by gotfork ( 1395155 )

        The /. title of this article is wrong, stupid and misleading.

        Seconded. Just to clarify, the only thing that's changing here is the dispersion relationship. In graphene the energy of carriers grows linearly with momentum due to strong spin-orbit coupling. In most materials the energy grows proportional to the momentum squared. People have known for a long time that you can do all sorts of things to graphene to change the dispersion relationship so that it acts like other materials. For a bit of a overview see http://www.lbl.gov/publicinfo/newscenter/pr/2008/ALS-g [lbl.gov]

      • by radtea ( 464814 )

        Electrons in a graphene sheet behave like massless particles

        Minor nit: it ain't electrons that behave this way, but quasi-particles resulting from the interaction of free electrons with the substrate. The equations of motion describe the quasi-particle dynamics, not the bare electron dynamics.

        But otherwise, yeah. What you said.

      • by blair1q ( 305137 )

        So what you're saying is that he's saying that when you make nanotubes fom graphene you take away some of the magic that making the graphene gave you.

        That makes a lot more sense.

      • by JamesP ( 688957 )

        Now, I wonder what would happen when putting electrons in a C60 buckyball...

        • by Thud457 ( 234763 )

          Now, I wonder what would happen when putting electrons in a C60 buckyball...

          Two electrons enter, one electron leaves...
          Who runs Bartertown?!

      • It almost sounds like you're saying that sometimes they're a wave and sometimes they're a particle.

    • by Saishuuheiki ( 1657565 ) on Friday October 22, 2010 @01:18PM (#33987298)

      It seems to me that it's poorly worded. As far as I can tell, it's not 'creating mass' so much as it is 'creating dependency on mass'

      Normally the equations governing movement of electrons are independent of mass. In graphene it appears we should be able to make it dependent on the mass of the electron.

      So I believe the article is saying that they believe they can make some particles that didn't appear to have a mass have a new equation for movement that reveals a mass for them. The article mentions that there's a theory that these particles didn't have a mass before this point; that the actual changing of rules that govern movement creates the mass.

      I like to think of it as the equivalent of creating charge. You're not actually making anything; you're just moving electrons/protons so they're out of balance. Essentially this could be the same thing with gravity.

      Now if this could be reversed to make something mass-less, that would be interesting

      • by lgw ( 121541 )

        That sounds right.

        TL;DR - the electrons (that always have mass) will act like it in this tube thingy, instead of the normal acting like they don't have mass.

      • That would be one hell of a trick, given that electrons have less mass that either protons or neutrons do. And that even in Hydrogen where the difference is smallest you still don't have anywhere near enough mass to make that happen.
      • Re: (Score:3, Insightful)

        by blair1q ( 305137 )

        Normally the equations governing movement of electrons are independent of mass.

        That's only because the mass of the electron (1/1900th the mass of a neutron or proton) is usually negligible in the dynamics you're calculating.

        In superconductors, the equations really do eliminate the force of mass*acceleration from consideration, along with any other forces the electrons would normally be expected to react to (that would contribute to transfer of energy that would make the nuclei vibrate randomly in place; i.e., resistance heating).

        Apparently all that's happening here is that he's predic

    • Re: (Score:3, Informative)

      by Badge 17 ( 613974 )
      Math trick slash analogy. In graphene, electrons behave like massless particles traveling near the speed of light. What this means is that energy increases linearly with particle speed, rather that KE = 0.5 m v^2 , like you learned in physics 101. Particle physics people have argued that adding compact dimensions (rolled up) will change interactions, and these guys have showed that you can also get electrons to act like massive relativistic particles in tubes of graphene. I'm not an expert in the field,
      • by radtea ( 464814 ) on Friday October 22, 2010 @02:31PM (#33988412)

        In graphene, electrons behave like massless particles traveling near the speed of light.

        No, electrons do not.

        "Charge carriers", which in the case of graphene are quasi-particles that result from the interaction of electrons with the more-or-less 2D medium, do.

        The difference is tremendously important, althought admitedly your explaination is about a million times better than the gibberish in the headline and summary.

        This is interesting and legitmate physics: charge-carrying quasi-particles in 2D graphene behave as massless particles in a 2+1D spacetime (according to the paper, at least.) If you role the sheet up the dynamics of the quasi-particles becomes that of massive particles in a 1+1D spacetime. This allows experimental realization of systems described by relativistic dynamics (the Dirac Equation) under much simpler circumstances than one might generally expect.

        This is similar to the research on "solid state monopoles" which behave like Dirac monopoles over large distance scales. They allow the study of a wide range of phenomena that are otherwise inaccessible (and in the case of Dirac monopoles, entirely theoretical!)

        No mass in the ordinary sense of the term is created in the situation the paper describes. If you weighted the system with a sufficiently sensitive balance you would not find that the apparatus weighted more when the graphene sheet was rolled up.

    • by CraftyJack ( 1031736 ) on Friday October 22, 2010 @01:57PM (#33987898)
      It's a "math trick", and not a new one. From TFP:

      Recall that this method of mass generation has been utilized exclusively in high energy physics, supergravity, string theory and related fields [9]. To the best of our knowledge, the present work constitutes the first successful application of this method in condensed matter physics. Another example of space compactification is found in a system consisting of a stack of graphene sheets with coupling between the layers making the massless 3D problem equivalent to an effective massive 2D problem [8].

      In other words: "We applied an existing math trick to a new area of theoretical physics, and things look good so far."
      You take that, feed it to the "Technology Review" blog, and you get:

      The amazing properties of graphene now include the ability to create mass, according to a new prediction.

      ...which is not quite the same.

    • Re: (Score:3, Informative)

      by mcgrew ( 92797 ) *

      I asked a similar question, and this guy seems to have nailed it. [slashdot.org] I hope the mods notice his answer.

  • I said, "No way!", but mathematics said, "All your English are belong to us." [wikipedia.org]

    • Thank God. I thought for sure that George W. Bush had become a /. editor. The extra "i" does leave open the possibility that Dan Quayle is working as a copy editor.
    • I’m still trying to figure out why “compaction” isn’t the correct word, other than some physicist bastardized the word and it caught on.

      And for what it’s worth, although “compactification” seems to be a word (it’s in the Merriam Webster Unabridged), compactify and compactifying are not.

  • We call it (Score:5, Funny)

    by Anonymous Coward on Friday October 22, 2010 @01:01PM (#33987028)

    the Mass Effect.

  • Fake mass = artificial gravity?
    • I was thinking this too, but it appears as usual that the summary is wrong and that this is just a way of reimagining a problem to better do calculations. No gravity guns/starships to see here, move along.. :(

    • Gravity/mass isn't created. It exists and it's being made to behave like it exists (the mass presumably comes from the electrons). Plus they haven't discussed the input energy required to "compactify".
  • Sorry, but I call BS. A graphene sheet is NOT two dimensional and after rolling it into a tube, it is NOT one dimensional. One dimension very thin != lack of dimension.
    • Re:Not 1-dimensional (Score:5, Informative)

      by zero_out ( 1705074 ) on Friday October 22, 2010 @01:21PM (#33987340)
      It's not the dimensions in which the graphene occupies that is 1D. It's the dimensions along which a particle moves. Graphene, being 1 atom thick, would normally be a sheet, occupying 3 dimensional space. The particles would move along the graphene in 2 dimensional space. If you rolled the sheet into a single atom thick carbon nanotube, it still occupies 3 dimensional space, but the particles will only move along 1 dimension.
    • by Xelios ( 822510 ) on Friday October 22, 2010 @01:26PM (#33987416)
      If you RTFA they clarify that the tube is 1 dimensional as far as the electrons and holes are concerned, probably because instead of being able to move across the sheet of graphene in both the x and y directions they're now constrained to move only in one direction, up and down the nanotube. If there's only one possible axis of movement, then you're effectively in a 1 dimensional system.
  • This is either total crap or Nobel Prize material. I'm not qualified to say which. Who's endorsing this paper?

  • I'm sorry, but "compactifying" just sounds so much like something Larry the Cable Guy would say...
  • by 140Mandak262Jamuna ( 970587 ) on Friday October 22, 2010 @01:40PM (#33987648) Journal
    Let us say you are hanging outside by holding on the window bars a long train (make it infinitely long train, who cares? it is theoretical physics, Also make it a train in India because most trains in Europe and USA have glass windows with no grab holds) and the train is moving with some speed. The outer walls of the train would not grab you and hold you against gravity. You have to hang on with your dear life. But if you curve the train track to make it circular, you will experience a centrifugal force that pins you to the outer wall of the train, and you can even let go of the window bars and shout, "Look! Ma! No hands".

    Of course you know that centrifugal force is not a real force, but a pseudo force you conjure up if you are working on a reference frame attached to the train. From an inertial frame of reference, your velocity is being changed constantly. Change in velocity is acceleration. The change in direction would be towards the center of the circular track. That acceleration is centripetal acceleration. The train is exerting a force centripetal force on you. The reaction from your body on to the train for that force times friction coefficient gives you the force that is holding you still stuck like a fly on the wall of a train moving in a circular track.

    As one who has spent years hanging on to the window bars of trains and buses in Chennai, India, let me tell you, no matter how many Einsteins tell you that is a pseudo force, it felt real and that I am still living, not having been run over decades ago by the next bus or train proves that centrifugal force is real. Not pseudo.

    Similarly the fermions seem to be having a mass to satisfy some equation in some frame of reference after some coordinate transformation. But really it is not creating any mass.

    • This is the first really useful explanation of the mechanism at work in what the paper authors are trying to describe. If only theoretical physicists and tech blog writers were so lucid in their writing.


    • Nice explanation, thx But why does your train need to be infinitely long? I would argue an infinitely long train has quite a problem driving in circles. Unless of course you hook the front of the loc to the end of the last wagon...
    • by Nethead ( 1563 )

      What you are feeling is you hitting the side of the train as you were flying through the air.

    • It seems to me that all forces, if properly understood, are in some sense pseudo forces.

  • Inertia Drive.
  • We finally found it. If we make enough graphene sheets, we could save the universe from the big freeze, generating enough mass to make the universe to be cyclical.

    What is more, considering the color of the coal, maybe we finally found that predicted "dark matter" that could had done that effect.
  • I'm on my way to a cold fusion seminar given by Professor Ponzi. Please respond ASAP.

  • This sounds like a theoretical basis for a warp drive. If that which is massless can be made to have mass, one could imagine a strip of graphene that rolls up to form a nanotube further up the strip. Put a charge on the array and you create mass, which will fall back toward the bulk of the ship. when it falls out of the nanotube and back into the graphene, the mass disappears, leaving you with net forward thrust Find a way to dynamically zip/unzip the nanotube, and you should be able to use a flow of cu
  • According to Abdulaziz Alhaidari's calculations, if one were to roll up graphene into a nanotube, this could compactify dimensions (from the sheet's two down to the tube's one),...
    The sentence above conveys a wrong impression that tube is one dimensional. Dimensionality of a tube is still the same as of the plane and it is still two. What is different is its topology. Tube has one one dimension with a topology of a line (infinite in both directions) and another one which is a circle and is compact. And it,

Thus spake the master programmer: "When a program is being tested, it is too late to make design changes." -- Geoffrey James, "The Tao of Programming"