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Making Magnetic Monopoles and Other Physics Exotica 104

Posted by kdawson
from the north-just-north dept.
PhysicsDavid writes "Physicists have been searching for magnetic monopoles pretty much since they knew about magnetism and definitely since Maxwell unified electricity and magnetism. Now some researchers have shown that using some weird mirror materials will allow them to create something indistinguishable from a monopole in a lab experiment. A paper about it was published today in the journal Science as an advance online publication (abstract; full article available only to AAAS members). The technique looks like it could be used to create analog systems of other kinds of exotic particles that haven't yet been observed, such as axions. The theorists who proposed this are working with experimenters to try to create these systems and study them in depth this year."
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Making Magnetic Monopoles and Other Physics Exotica

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  • by ErroneousBee (611028) <neil:neilhancock ... minus herbivore> on Friday January 30, 2009 @12:38PM (#26667619) Homepage

    I thought there was only one magnetic monopole, and one photon, in this universe.

    • by digitrev (989335)
      Umm, what brought you to that conclusion? We're fairly certain that there are multiple photons, and no evidence of magnetic monopoles.
      • by geckipede (1261408) on Friday January 30, 2009 @01:13PM (#26668167)
        I think he is referring to the way that Feynmann diagrams allow you to represent an antiparticle as being a particle moving backwards in time. A particle/antiparticle pair then just becomes one particle going forwards and backwards in a loop. There was some talk that this way of looking at it may be physically real and that all particles are one, but taking a really circuitious route through time. It doesn't hold up well because there isn't enough antimatter around to allow it as far as we can see. I'm not sure it was ever supposed to apply to photons in any case.
        • Re: (Score:2, Informative)

          by MikTheUser (761482)

          I'm not sure it was ever supposed to apply to photons in any case.

          Probably not, since photons, being their own antiparticles, never had arrows attached to them in Feynman graphs to begin with.

        • by ErroneousBee (611028) <neil:neilhancock ... minus herbivore> on Friday January 30, 2009 @01:23PM (#26668279) Homepage

          I thought it still sort of worked for photons, cos they are their own anti-particle.

          My party piece is to bore anyone who will listen with an argument that the universe only needs one photon travelling backwards and forwards in time.

          But the WTFs are usually reserved for the followup where I set fire to my head.

          • But the WTFs are usually reserved for the followup where I set fire to my head.

            Which won't actually hurt since there's only one photon in the universe anyway.

        • I mean it is true we do not OBSERVE much antimatter in this universe, but that doesn't mean it is not present in some sense:

          A) It could be in some other part of the universe beyond our effective observational horizon. Granted there are some reasons to think not, but it is a possibility.

          B) It could be that the antimatter simply exists in some 'other place'. Given that we haven't at all settled the actual architecture of spacetime, it could be that the antimatter is in a location which is either topologically

          • by hesiod (111176)

            I mean it is true we do not OBSERVE much antimatter in this universe, but that doesn't mean it is not present in some sense:

            Perhaps it's all clumped together at another point on the time loop. Once the largest antimatter clump and largest matter clump come back together in the time loop, there's a big bang.

            What? No, I don't have any idea what I'm talking about, thank you.

            • by Nazlfrag (1035012)

              Why not? When the big bang banged, it sent the universe hurling in every other direction, so why not both forward in time and backward in time. Of course, antimatter running backwards through time is identical to matter running forwards, thereby creating the parallel universe where everything is the same except that evil is good and they all have goatee beards.

              • by hesiod (111176)

                parallel universe where everything is the same except that evil is good and they all have goatee beards.

                At first I read that as "goatse beards" and though "Boy, that is evil!"

          • by nusuth (520833)

            I mean it is true we do not OBSERVE much antimatter in this universe, but that doesn't mean it is not present in some sense:

            A) It could be in some other part of the universe beyond our effective observational horizon. Granted there are some reasons to think not, but it is a possibility.

            B) It could be that the antimatter simply exists in some 'other place'. Given that we haven't at all settled the actual architecture of spacetime, it could be that the antimatter is in a location which is either topologically distant/inaccessible or in dimensions not readily visible to us.

            C) Antimatter could be segregated in a different part of time itself. If we imagined that the arrow of time in our universe reverses every now and then, some form of oscillating universe, then perhaps we would find that when time runs backwards, matter looks like antimatter and that may balance the books.

            All of that could happen. Perhaps it is just that our assumptions about how antimatter looks from distance is flawed. Or it may be just that we have a matter bias in our minds and refuse to see evidence of antimatter around us. Or mighty invisible aliens controlling our experiments may be rigging them to conceal the fact antimatter is plenty... Once you start making hypotheses based on what we don't know, don't observe or can't observe, matter-antimatter asymmetry ceases to be a problem, but I hope you real

            • Any hypothesis would have to make predictions which could be observed, it would have to be falsifiable. I am not suggesting any of my basically idle speculations are anything like solid theories. Nor am I one of those deluded posters you see on so many forums who somehow believe their random thoughts are amazing new groundbreaking scientific insights (which of course the "hide bound" ultra-conventional scientists simply "cannot see"), lol.

              My main point was that if a theory is advanced which can explain wher

              • by nusuth (520833)
                I fully agree with parent. My gripe with ggp was none of your speculations (except "not readily visible dimensions" of B, where "readily" suggests they might be visible with enough understanding of theory and more advanced technology) had observable qualities, at all. No one can ever know if there is antimatter trapped in causally disconnected parts of the universe, residing in inaccessible dimensions or in a shadow universe going back in time since bing bang.
                • But I would wager that many people 100 years ago would have said that some of the things we observe today would remain forever hidden as well. Obviously if some part of the universe really is fundamentally unobservable and causally disconnected from the part we can observe then any theorizing (to use the term loosely) we might engage in relative to that is no more scientifically valuable than a fantasy novel.

                  But it may turn out that there are some subtle effects we can measure. Some formulations of quantum

    • Re: (Score:3, Funny)

      by Anonymous Coward

      I can see how you might confuse photons with zune users.

  • nobel (Score:3, Interesting)

    by tritonman (998572) on Friday January 30, 2009 @12:43PM (#26667705)
    I think this would be a no-brainer for the nobel prize if they can really make something equivalent to a magnetic monopole.
    • Re: (Score:3, Interesting)

      by digitrev (989335)
      Absolutely. The better part is what this would mean for Maxwell's equations. If it turns out that you can create something indistinguishable from a magnetic monopole, then we have to start some very serious research into the implications.
      • Re: (Score:3, Funny)

        by corsec67 (627446)

        then we have to start some very serious research into the implications.

        Traveling north or south becomes much cheaper than heading east or west?

        • Re:nobel (Score:4, Informative)

          by pla (258480) on Friday January 30, 2009 @01:54PM (#26668707) Journal
          Traveling north or south becomes much cheaper than heading east or west?

          Bigger than that... A real magnetic monopole means real over-unity generators (aka "perpetual motion", aka "free energy"). That alone makes me take this "discovery" with a grain of salt the size of Bonneville.

          If this amounts to more than sloppy science or outright fraud, I would guess that it comes with the same sort of huge disclaimer that quantum teleportation has regarding FTL information transmission - "It just doesn't work that way".
          • by wsherman (154283) *

            Bigger than that... A real magnetic monopole means real over-unity generators (aka "perpetual motion", aka "free energy").

            I had actually been wondering about that myself. Do you have a reference? I did some google searches and looked over the Wikipedia page on magnetic monopoles but didn't see anything about magnetic monopoles violating the laws of thermodynamics.

            There's a chance that a magnetic monopole might allow static magnetic levitation (Earnshaw's Theorem) but I haven't actually seen anything definitive on that either so it's pure speculation on my part.

          • by evanbd (210358)
            [[citation needed]]
          • How's that? Electric charges and gravity behave like monopoles but they don't result in perpetual motion. How would a magnetic monopole be different?

            • by pla (258480)
              How's that? Electric charges and gravity behave like monopoles but they don't result in perpetual motion. How would a magnetic monopole be different?

              We do extract work from electric "monopoles", with the annoying problem that they weaken proportional to the amount of energy you extract energy from them - Except at the level of single electrons, which we currently only know how to herd into tiny channels and use in a way not much more elegant than how a waterwheel or pneumatic drill works.

              We extract qui
              • These have nothing to do with perpetual motion. For instance, the Hoover Dam harness energy that ultimately came from the sun.

      • Re:nobel (Score:5, Informative)

        by MikTheUser (761482) on Friday January 30, 2009 @12:55PM (#26667899)
        It wouldn't matter much at all to Maxwell's equations. The model is well fit to accommodate magnetic monopoles, if the

        div B = 0

        equation were modified to read, say

        div B = rho_m / mu_0

        in analogy to Gauss' law. The defining qualities of Maxwell's model, such as the compliance with relativity, would remain intact.

        For further reading on this, David J. Griffiths' 'Introduction to Electrodynamics' is many a professor's first recommendation to students.

        • by digitrev (989335)
          Ahh, good ol' Griffiths. How I agonized over the problems in that book. I suppose that would work, but it I still think the implications are far reaching. I mean, Maxwell's equations at the core of much of the technology we rely on today. To think that we might be able to do even more is impressive.
          • by cc1984_ (1096355)

            Not sure how well a monopole would fit with my view of the world.

            Sure, the equations would be symmetrical, but since the field is not necessarily continuous, you could get energy for nothing (imagine that monopole following the field lines around a current carrying wire, getting faster and faster because of the infinite potential in the wire.)

            But then again, I don't know any covarient e-mag, so there might be a gap in my knowledge.

            • by wsherman (154283) *

              Sure, the equations would be symmetrical, but since the field is not necessarily continuous,...

              I was wondering similar things myself but then I got to thinking that the field would only be discontinuous in the classical approximation of a point "charge" and that you'd have to mess with quantum and wave functions to really understand what was going on.

              ... you could get energy for nothing (imagine that monopole following the field lines around a current carrying wire, getting faster and faster because of the infinite potential in the wire.)

              The question of how a magnetic monopole would interact with an external magnetic field is quite interesting but also rather tricky. I assume that there are physicists who have worked it all out precisely but, just off the top of my head, it's not obvious

          • by Artraze (600366)

            The implications for Maxwell's equations is basically nil. Why? Because div_B=0 works perfectly for every application yet encountered. Thus, regardless of what div_B may end up being once monopoles are accounted for it'll end up being zero basically 100% of the time, unless someone wants to throw a monopole into the situation (on purpose) to spice things up a little.

            That being said, it's not really like monopoles do anything much in the context of ME since magnetic fields only matter if they're varying,

        • by tenco (773732)
          You can do this even without having real monopoles by gauging the equations so that every mass which has electromagnetic charge has a certain amount of electric and magnetic charge (gauge invariance of Maxwell's Equations). For this, the ratio of electric charge to magnetic charge has to be equal for all these masses. This will make the equations symmetrical.

          So I'm wondering how the equations will change if there's a real magnetic charge. Does this case distinguish itself from the gauge case in any way?

          • by tenco (773732)

            (gauge invariance of Maxwell's Equations)

            This should be "gauge invariance of electrodynamics". The equations will change for a different gauge, as I wrote later on.

        • by goombah99 (560566) on Friday January 30, 2009 @02:24PM (#26669175)

          Back when I was designing magnetic bubble memory we used to use monopole equations to represent the bubbles.

          No violation of physics here because they were always paired. But the pairs in the media are well separated so it's a btter approximation to use two monopoles than a dipole.

          That is to say, each bubble is really a cyllinder running from the bottom of the thin film to the top just like it is in vertical recording HD. You can treat the top as a monopole and the bottom as an opposite monopole and get a very good model of bubble-to-bubble interactions.

        • by logicnazi (169418)

          I think the point was that if there were magnetic monopoles then Maxwell's equations would be even more elegant because there would be more symmetry between the electric and magnetic fields.

      • by SciBrad (1119589)
        Well in a sense it is already known how the Maxwell equations would transform with hypothetical monopoles (you get the divergence of B to look like the divergence of E and there is a "monopole current" term in the curl of E equation). In any region where there isn't a monopole everything would remain the same, so nothing already known changes. But for regions where we'd have these monopole like things quite a few equations where you wind up with div B would become more interesting to say the least!
      • by Roger W Moore (538166) on Friday January 30, 2009 @01:00PM (#26667959) Journal

        If it turns out that you can create something indistinguishable from a magnetic monopole, then we have to start some very serious research into the implications.

        This is "indistinguishable" from a monopole in the same way that an image in a mirror is "indistinguishable" from the real object. While extremely interesting there will be bound to be edge effects given the finite size of the mirror and there must physically be a second pole somewhere because the material cannot spontaneously acquire a net magnetic charge...unless there is some significant new physics occuring. Hence I would take "indistinguishable" with a very large grain of salt. It is an extremely interesting result though.

      • My physics teacher used to talk about how the equations would change. del dot B would equal some measure of magnetic charge density rather than zero, while del x E would equal the partial of B wrt t + some measure of magnetic current density.

        Basically the equations just become more symmetric; electric charge has monopoles after all. Certainly there will be a wide range of implications.

        • Re: (Score:3, Interesting)

          by Anonymous Coward

          Most notably, if even a single magnetic monopole exists in the universe, electric charge quantization is the result [wikipedia.org], as shown by Dirac in 1931. We currently don't really actually know why the hell things are quantized, so that would be ...interesting. If anything, it's a bit peculiar that electric charge is quantized given that we haven't seen magnetic monopoles to date (of course if electric charge wasn't quantized we wouldn't exist... but anyway...)

          Quantization in general is weird and inelegant and ugly

      • by OldFish (1229566)
        Actually, there is already a way of hiding the apparent lack of magnetic monopoles in Maxwell's equations. You can write them in a symmetric form and everything works just fine without the distinction between electric and magnetic monopoles. The lack of monopoles implies that the ratio of magnetic "charge" to electric charge is a constant. The observation of a free monopole could be sorta cool.
    • by nospam007 (722110) *

      Sorry for RTFA but it just says, somebody had an idea that a certain theoretically existing matter could help doing such a thing, if it existed and if somebody would identify it.

  • by Anonymous Coward

    Whenever I play in the car the pieces end up flying all over, so yeah, magnetic Monopoly would be great!

  • by gEvil (beta) (945888) on Friday January 30, 2009 @01:04PM (#26668023)
    There's an instructable for making magnetic Monopoly right here [instructables.com]. As for finding the physics erotica, your on your own--I'm at work right now...
  • by shawn(at)fsu (447153) on Friday January 30, 2009 @01:19PM (#26668219) Homepage

    That's easy. Take a regular magnet and cut it in half, gees do I have to do all the heavy thinking around here.

    • by Chris Burke (6130)

      Take a regular magnet and cut it in half, gees do I have to do all the heavy thinking around here.

      Well I'm handling all the heavy drinking so somebody has got to pick up the slack.

  • by rk (6314) on Friday January 30, 2009 @01:20PM (#26668223) Journal
    Now, do we go for Unified Field Theory and get tachyon bolt weapons, or Nanominiaturization and score the hovertank chassis?
    • Re: (Score:2, Funny)

      by Anonymous Coward

      I'm just waiting for Centauri Genetics, but I'd settle for Controlled Singularity.

  • The Superconducting Super-Collider to be built in Texas fifteen years ago used magnetic monopoles in its design. In my physics class in 1991 we received a lecture visit from an SSC representative who casually hand-waved the matter of inventing such a thing.

    In hindsight I see that perhaps the SSC project really was as overpromised as Congress, in cancelling it, suspected.

    • Re: (Score:3, Informative)

      by meringuoid (568297)
      The Superconducting Super-Collider to be built in Texas fifteen years ago used magnetic monopoles in its design. In my physics class in 1991 we received a lecture visit from an SSC representative who casually hand-waved the matter of inventing such a thing.

      Er, wow. Citation? The SSC was pushing the boundaries all right - the clue's in the name, superconducting, and that's difficult to do even now as witness the LHC explosion - but I hadn't heard that it would have used magnetic monopoles. Possibly it migh

      • by Hartree (191324)

        The guy from the SSC was probably mentioning magnetic quadrupoles which are an assembly of electromagnets used to confine the beam.

        The SSC certainly didn't use magnetic monopoles in its design.

  • I was reading TFA that was linked, and the author said something about the monopole inducing a current "without dying out." So I presume that he is using some sort of metal in a device to test this current. If the current doesn't die out, isn't there constant heat loss in the metal due to resistance from the current? Where is that heat loss made up, concerning conservation of energy?
  • I never really got the idea of magnetic monopoles. I studied them for a couple weeks, but they just seem so intuitively wrong. Magnetic fields are caused by electrons moving... but if you have a monopole, that's like saying that you have electrons going somewhere but coming from nowhere. Or coming from somewhere and going to nowhere. This isn't possible though because energy is conserved -- even if you blew up the electron, it'd still just turn into waves that are still there. It is a fundamentally fla
    • Magnetic fields are caused by electrons moving

      Are you sure? Maybe the point-"particle" phenomenon known as "the electron" is simply the result of a self-perpetuating magnetic field.

    • by omnichad (1198475)
      So the electrons are coming from an alternate universe? Free energy for everyone! Until it totally destroys a solar system.
  • Magnetic monopoles are easy. Take an iron sphere, cut it in half. Cut those hemispheres in half, then cut those lunes in half. Magnetize them all the same way, say N at the point and S at the surface, then reassemble the sphere. Voila, a S monopole.
    • by zehaeva (1136559)
      except that you couldn't keep the sphere together, all the norths in the center would repel and blow the sphere apart.
      • by Chris Burke (6130)

        Not if the magnetic field is weaker than whatever you use to hold them together.

      • I'll just get Chuck Norris to hold them together.
      • by cryptocom (833376)

        Not true at all. I've done something similar. I took two ring shaped magnets and superglued the repelling poles together using a plastic clamp. After the glue had set, the entire assembly was attractive on all sides, but the space in the center repelled objects inserted there. Bingo. Monopole. No exploding necessary.

    • That most certainly does not result in a monopole. You'd get a quadrupole I think.
    • by MorePower (581188)

      I'm no physicist, but my instincts as an electrical engineer tell me that the flux lines from the north poles would wedge themselves into the cracks between each of the pieces in an effort to close the loop. Probably this very dense flux would forcibly re-magnetize the edges of each iron piece so that the surface of the assembled sphere would be S in the middle of each piece and N all around the edges.

      Any physicists want to chip in and confirm or debunk this?

      • by wsherman (154283) *

        I'm no physicist either but what you say sounds right at a practical level.

        At a theoretical level, I strongly suspect that everything would cancel out. That is, as long as the magnetization is spherically symmetric, there will be no magnetic field outside the sphere.

  • by philspear (1142299) on Friday January 30, 2009 @01:57PM (#26668769)

    I can't believe people are having a hard time with this. It's easy! Just cut off the pole you don't want!

    Geez!

  • Just in time for Valentine's Day!
  • I'm sure I'm ascribing an incorrect visualization to the phenomena, but my image of a magnetic pole is that of a motion in liquid - like a propeller in water - line two propeller in a row, and they will work in sync pulling water from the input to the output, put two propellors face to face, and they will 'repulse' each other, i.e. create a high pressure region.

    I've always visualized the lines of force in magnets as the same thing, with electrons. Which can't really be right, because if that were the case,

    • by wsherman (154283) *

      I'm sure I'm ascribing an incorrect visualization to the phenomena, but my image of a magnetic pole is that of a motion in liquid - like a propeller in water - ...

      Just to add my two cents, I visualize a magnetic field as three superimposed scalar fields of potential energy.

      Classically, potential energy is the integral of force with respect to distance or, equivalently, force is the derivative of potential energy with respect to distance. To use slightly more sophisticated language, force is the gradient of the potential. In three dimensions, imagine a room with hot spots and cold spots. The temperature would correspond to the (scalar) potential energy (field) and arr

    • by paulgrant (592593)

      Picture putting your propeller against a solid wall (negative pressure region towards the wall)
      Picture your propeller developing such a high pull that it literally sucks material through the wall (or in the proposed case above, from surrounding regions of the wall similar to ground effect in aerodynamics)

      Magnetic monopole ;)

      Magnetism (the movement of electrons) is usually limited to the surface of a material (or some penetration depth thereof depending on field strength). in essence what you want is a posit

  • So does that mean we can expect to travel around by mag tube any time soon? :D

  • I guess /.'rs aren't that excied about these news, or I am certain the legal link for the full PDF paper [scienceonline.org] would have been posted already, as it lies right there in Google

    • by n6kuy (172098)

      That's for the supplementary stuff.

      This link [scienceonline.org] works for me for the main article. But that may be because of where I work.

  • I heard a rumor that the first person to make a true monopole gets a get out of jail free card...what? that's spelled differently? Eh, whatever

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