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I understand the significance to physics, but what can a magnetic monopole be used for assuming we could free them from spin ice and put them to work? What would be a magnetic version of electricity?


EDIT

Sorry this wasn't clear. The question is mixed between the quasiparticle and the theoretical elementary particle based on some similarities between the two. I am more interested in the quasiparticle and if they have properties in some way that are similar to particle version:

There are a number of examples in condensed-matter physics where collective behavior leads to emergent phenomena that resemble magnetic monopoles in certain respects, including most prominently the spin ice materials. While these should not be confused with hypothetical elementary monopoles existing in the vacuum, they nonetheless have similar properties and can be probed using similar techniques.

http://www.symmetrymagazine.org/breaking/2009/01/29/making-magnetic-monopoles-and-other-exotica-in-the-lab/

"The Anomalous Hall Effect and Magnetic Monopoles in Momentum Space". Science 302 (5642) 92–95.

"Inducing a Magnetic Monopole with Topological Surface States"

"Artificial Magnetic Monopoles Discovered"

and comments in articles about quasi-particles like this:

Many groups worldwide are currently researching the question of whether magnetic whirls could be used in the production of computer components.

led me to wonder what application might they have? Mixing these two concepts is probably a bad way to present this question. A true magnetic monopole would effect protons whereas the artificial ones don't.

What I don't understand is what advantages an artificial magnetic monopole would have. And does this relate to some theoretical aspect of a true monopole?

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I suspect nothing, since electric charches $e$ and magnetic charges $q$ are related by $ e\, q = 2 \pi$. Both interact with photons, and the magnetic south and nord poles would just take the role of positive and negative electric charges. –  Dilaton Jun 8 '13 at 19:25
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@Dilaton In the spin Ice model considered by the OP, we cannot say that eg=2$\pi$. These are quasi particles, and ends are connected by dirac string like object which can be observed through interference experiments. –  Prathyush Jun 9 '13 at 1:32
    
@Dilaton From what I can tell you're correct even if e q != 2π in spin ice. –  user6972 Jun 9 '13 at 17:45
    
Charge dissipates, leaks and flows. Magnetic monopole would be quite stable upon contact with something. –  Waqar Ahmad Jan 5 at 8:04
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Also see the Wiki page on magnetic monopoles; the section on Duality Transformations summarises why @Dilaton 's answer is correct. –  WetSavannaAnimal aka Rod Vance Jan 6 at 0:52

4 Answers 4

Many years ago I considered the situation of a genuine monopole continually threading through the middle of a wholly superconducting loop. So we have two interlocking Roman rings - one an electric charge circuit, the other a magnetic charge circuit. Depending on the relative sense of circulation, either the monopole gains energy at the expense of the supercurrent, or vice versa. Well actually, it might not be that simple.

Thing is, superconductivity is intimately associated with the usual vector potential A, and a supercurrent will only change in response to a change in an externally applied A. Such as to maintain the line integral of net A around the supercurrent invariant. But A is only generated by moving electric charge. The hypothetical 'back emf' of circulating monopole would be owing to an E field the analog of the B field of moving electric charge. On a time-average basis it would be steady given a steady monopole current. Hence of a fundamentally different character to an $E = -dA/dt$ owing to time-varying electric current, that the supercurrent would know and respect. Hence regardless of whether circulating monopole gains or loses energy in following along the lines of B generated by the supercurrent, the supercurrent itself will do squat. There is a similar dilemma when it comes to the predicted net force/torque balance - or rather imbalance.

Upshot is, one either accepts that energy-momentum conservation would dramatically fail, or take the scenario as proof that a genuine monopole cannot exist!

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My suspicion is that a dipole magnet will infact behave as a battery, in this magnetized version of electricity you want to consider. The potential difference across the terminals of the magnet can be used to extract energy, like run a motor. However it will be soon followed by an accumulation of magnetic monopoles on both N and South ends of the magnet, making the magnetic battery eventually unusable. To resuse it all you have to do is use external work to separate the monopoles from the poles of the magnet.

Also Note, that you will not be able to free your magnetic monopoles from Spin Ice. So you will be forced to make wires out of spin ice.

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Your first paragraph is describing the magnetic monopole analogue of a capacitor. –  Steve B Jun 18 at 19:17

Partly related to your question, Artificial Magnetic Monopoles Discovered, from an article in ScienceDaily just late last month. The monopoles apparently act the same as the ends of a dipole magnet, as has been suggested by Dilaton in the comment above. A more comprehensive article is from Particle Data Group.

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From the article: "Many groups worldwide are currently researching the question of whether magnetic whirls could be used in the production of computer components." How so? –  user6972 Jun 9 '13 at 17:30
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I am not entirely sure, but it is indeed interesting, something worthwhile for you to research. –  user24901 Jun 10 '13 at 9:33
    
The Particle Data Group article is about real magnetic monopoles (elementary particles); the ScienceDaily article is about magnetic monopole quasiparticles. They are unrelated, and it is misleading for you to suggest that they are the same thing. See en.wikipedia.org/wiki/… –  Steve B Jun 18 at 19:15

Magnetic monopoles are thought to be carriers of magnetic force similar to electrons and electrical charge. If you can generate and use these particles you could expand the number of ways we can manipulate electromagnetic waves. Two ideas that spring to mind immediately are the creation of a DC transformer that does not require superconductors and the ability to create some nicely huge magnetic fields in confined spaces.

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