# Talk:Magnetic monopole

## Clean up

New minor changes:

• Clean up slightly.
• Re-section the lead into historical/recent developments sections, to break the long succession of paragraphs.
• Use the colspan="x" for equations repeated in the table, why write multiple times when the colspan implies the equations fall under all top headings?
• Remove some repetition of ρm and jm in/after the Maxawell equation tables, re-stated 3 times in the article:
• first table: "ρm and jm are defined as above" then "in these equations ρm are...,
• second table: "where ρm and jm are...",
just once would be fine.
• Inserted Lorentz force into first table for consistent layout with other table, adjusted heading slightly
• Indent tables.
• Made dot product for divergence bigger for visibility, replace ⋅ with ∇•
• Moved the apparently out-of-place statement:
For a long time, the open question has been "Why does the magnetic charge always seem to be zero?"
randomly stuck before Maxwell's equations in cgs units, and moved it higher up since its a good start to the first (newly-headed) section.

07:42, 28 May 2012 (UTC)

Looks ok to me :-) --Steve (talk) 21:13, 31 May 2012 (UTC)
• In the section "Grand unified theories" there are two adjectives that should be reconsidered.
"most of which had the curious[according to whom?] feature of implying the presence of a real magnetic monopole particle"
I feel the use of 'curious' is intended to indicate irony, as if to say, although no monopoles are in evidence, most of the :GUTs require monopoles. I think the "according to whom" can be removed or at least satisfied with a footnote to this effect.
"the apparent problem of the observed scarcity of monopoles is resolved by..."
The adjective 'scarcity' should be changed to 'absence'. Although monopoles are expected to prove to exist and to be scarce, it is more precise and serves the article better to reiterate that monopoles remain unobserved. — Preceding unsigned comment added by Shellsunder (talkcontribs) 11:08, 28 October 2012 (UTC)
I reworded... --Steve (talk) 15:25, 28 October 2012 (UTC)

## Marko Rodin

Not a single mention to Marko Rodin (http://www.youtube.com/watch?v=RnjW1zROJPc), one way or another - is there a reason for that? 89.153.150.71 (talk) 13:00, 1 July 2012 (UTC)

Yes, see WP:UNDUE. --Steve (talk) 17:55, 7 August 2012 (UTC)

## "Appendix"

The newly added Appendix section is almost exactly copied from http://www.encyclopediaofmath.org/index.php/Magnetic_monopole, on the site that the poster described. It might be relevant material, but it should definitely be presented in a different format. Also, this article does not have anything like this addition in its 2006 history. Nat2 (talk) 00:22, 31 July 2012 (UTC)

I will clean up the referencing at least. It would help if people could actually reference properly, this has been done before (see for example the edit history of David Hestenes)... Maschen (talk) 11:28, 18 August 2012 (UTC)
Done, except I couldn't find [4] or [15] in the text so moved those references to the Notes section. Also cleaned up most of the formatting... Now to contact the editor/s responsible for the messy ref style, and notify others at Wikipedia talk:WikiProject Physics#Magnetic monopole and Yang-Mills theory so they can rewrite the section, as indicated by the above link... Maschen (talk) 12:10, 18 August 2012 (UTC)
The SpringerEOM license allows copying but requires attribution, and so this kind of copying should include a note along the lines of "tis article contains material from Springer EOM, licensed under the CC-by-SA and GFDL..etc." linas (talk) 14:04, 18 August 2012 (UTC)

## Article is confusing

I wonder that an article like this,"Magnetic monopole" in the present form may still exist. In the light of the fact that there do not exist any real particles justified to be called so, it is confusing, and should be revised, rewritten.Caboz (talk) 14:10, 1 September 2012 (UTC)

Can you say more specifically what you found confusing? --Steve (talk) 13:15, 2 September 2012 (UTC)

The article should inform the reader that no particle of material substance as a source of magnetic field do exist and therefore can not be found. It should make clear, that all phenomena which we call "magnetic" are the consequence of the motion of electric field (charge). And this it does not.94.113.59.212 (talk) 16:55, 2 September 2012 (UTC)

See this section. Maschen (talk) 17:02, 2 September 2012 (UTC)
I agree: The introduction section, the figure and caption at the top, section 1.1, and section 2 state over and over, in extremely explicit terms, that magnetic monopoles are not the explanation for any magnetism phenomenon ever observed. Short of flashing lights and audio warnings, I can't think how to make it any clearer!! :-P
Caboz, how much time did you spend reading the article before you posted this comment? A few seconds? Minutes? Hours? Which sections were you mainly paying attention to? Did you read any of the text of Sections 1.1 or 2? Did you read the figure caption at the top? (Please don't think these questions are accusatory! I am asking in good faith to understand whether and how the article needs improvement.) --Steve (talk) 12:39, 3 September 2012 (UTC)

Does this drawing help (from field (physics))?

Electric fields E due to charged particles (black/white) and an electric dipole moment d, and magnetic fields B due to an magnetic dipole m and magnetic monopoles (red/blue). Particles with either electric or magnetic charge in motion (velocity v) induce an electromagnetic field.[1][2]

Apart from the one in the lead there are no other diagrams... Maschen (talk) 08:24, 3 September 2012 (UTC)

I don't think it's relevant to the specific complaint of this section...is that what you're talking about?
More generally, I have mixed feelings, particularly I think the bottom right entry may cause confusion. For one thing, a magnetic dipole is not normally made of two magnetic monopoles (obviously), so depicting that unusual kind of dipole may cause confusion. For another thing, IF you made a magnetic dipole out of two magnetic monopoles, the B-field lines would not be closed loops as depicted, they would start at N and end at S exactly like the top-right entry. Other than the bottom-right entry, it's a nice demonstration of the classical behavior of a magnetic monopole, relevant to the Maxwell's equations section. --Steve (talk) 12:39, 3 September 2012 (UTC)
Yes I am referring to this thread/complaint. Also it explicitly states "magnetic dipole" and linked so I hoped people would see the magnetic dipole found in ordinary matter there, but to prevent the confusion you now pointed out I splitted the image into two new ones - one for monopoles and another for dipoles:

{{#invoke:Multiple image|render}}

Maschen (talk) 16:42, 3 September 2012 (UTC)
Caboz, is the confusion that although we have not found natural magnetic monopoles, we can still theoretically define and use the mathematical definition of pole strength (redirected to magnetic moment), and then all the mathematical "hype" about Maxwell's generalized equations, the quantization condition, Dirac strings and topology... Is that it?
Forgive me, but what do you mean by "the article in the present form may still exist"? I have no clue what this means... just trying to understand where you are coming from...
Although I don't fully understand the QFT/topology of it all yet either - the absolute brilliance and fascination of the duality overwhelms the confusion IMO... Maschen (talk) 17:37, 3 September 2012 (UTC)
Maschen, since you seem to make the changes to the images so readily, what do you think of merging the dipole dots into a single one, half red and half blue? I think that way everyone should be happy, as it suggests the limiting condition more closely. — Quondum 18:28, 3 September 2012 (UTC)
Sure, they have been overlapped, but I would rather not blend too much (i.e. not into one pole) else it would look more like a neutral magnetic pole i.e. no magnetic charge (!). Is this ok? Maschen (talk) 18:47, 3 September 2012 (UTC)
Better. Let's see whether you get any other comments. — Quondum 18:59, 3 September 2012 (UTC)
No-one has objected to adding it in 8 days. I will do so. Maschen (talk) 09:47, 11 September 2012 (UTC)

It seems to me that the last discussion brings only more confusion and no clarification of the problem. The fact is that there are no "particle-like" magnetic poles, and this fact should be respected anywhere in this article. The first sentence in the present form: "A magnetic monopole is a hypothetical particle in particle physics that is an isolated magnet with only one magnetic pole...." is confusing. It should state: "Magnetic monopole is a misleading technical term inducing the idea of existence of material particles with magnetic properties (magnetic charge)...." The article should be re-written keeping this fact in mind. http://en.wikipedia.org/w/index.php?title=Talk:Magnetic_monopole&action=edit# — Preceding unsigned comment added by 94.113.59.212 (talk) 10:34, 13 September 2012 (UTC)

Again - it states from the very beginning that magnetic monopoles have not been found, and are not the sources of magnetism as we know it (who says they "don't exist"?).
They can be defined mathematically with the property of magnetic charge, as stated in the article, and there are sections on Maxwell's monopole equations (which reduce to the normal equations when magnetic charges and currents are zero for the system in analysis), Dirac quantization condition etc.
The "misleading" part of your statement is not correct; if a magnetic monopole is found, it would be a new elementary particle (which would have mass). The first image clearly states this. Maschen (talk) 11:07, 13 September 2012 (UTC)
The IP presumably has an interpretation of the word "hypothetical" with the semantic of "suspected" rather than the absolutely neutral sense that it normally carries. Clarity would probably come to this discussion when differences in interpretation of the words being used are ironed out, not from arguments dealing with the article's content. — Quondum 12:18, 13 September 2012 (UTC)
Apologies to the IP if I sounded personally direct and irritated, it's certainly not my intension to patronize.
I can't really think how to make the wording clearer, and intend to leave it to those who are inclined and capable... Maschen (talk) 13:06, 13 September 2012 (UTC)
You're not the one who should be apologetic. IMO the IP is being excessively assertive/POV based on a misinterpretation; I was basically trying to suggest to you to avoid being baited. I (and evidently others) think the article is perfectly well worded in this respect. — Quondum 13:54, 13 September 2012 (UTC)

Note to the new drawings: In the new drawings the depiction of the electric field is OK, but that of the magnetic field is false, - the lines of magnetic induction B are not "product" of "magnetic monopoles N S" but of moving (orbiting) electrical particles (electrons), i.e. electrical current. So the drawings are not explaining reality but only the false idea of the author.94.113.59.212 (talk) 01:37, 14 September 2012 (UTC)

No. For the magnetic dipole from two monopoles: if you actually read the caption - you will find that it is the mathematical prediction of what the field would be if monopoles were found.
For the magnetic dipole in ordinary matter, that's just true. A magnet has a north pole AND a south pole. Yes it is a macroscopic effect and ultimately all magnetism results from currents.
Yes - I am well aware that electric currents are the source of magnetism, and have drawn a diagram of that too (a year ago, in fact):

{{#invoke:Multiple image|render}}

I wish you would quit insinuating us that we "don't know magnetism arises from electric currents" and quit your false assertion that "magnetic monopoles do not exist". There is no conclusive experimental evidence that they exist - we haven’t found them yet. The laws of EM are not violated if they exist, so I have no clue why you keep saying magnetic monopoles are a false formality.Maschen (talk) 02:02, 14 September 2012 (UTC)

can you please 94.113.59.212 (talk) 06:12, 14 September 2012 (UTC)explain why should we talk about "hypothetical particles magnetic monopoles" when we know that they do not exist, and all magnetic phenomena can be explained by real effect of moving electrical particles ? 94.113.59.212 (talk) 06:12, 14 September 2012 (UTC)

"... when we know that they do not exist" – we do not know this; all our observations are consistent with them possibly existing or possibly not existing. As the old chestnut says, absence of evidence is not evidence of absence. So you cannot use this is a premise. Hypotheses are useful for investigating possibilities in the absence of knowledge as to the truth of the hypothesis.
"... and all magnetic phenomena can be explained by real effect of moving electrical particles" – again, this is only true within the scope of our observations. Should magnetic monopoles actually exist, there will be magnetic phenomena that cannot be explained in terms of moving electrically charged particles.
One of the strengths of hypotheses is that they allow us to speculate, and to explore the feasibility of the hypotheses. At the time of Dirac's invention of his equation, positrons could not have existed, by logic similar to yours. Fortunately Dirac did not dismiss his equation on the grounds that no then-observed particle fitted the bill of that solution to his equation. — Quondum 06:43, 14 September 2012 (UTC)

I agree that "...hypotheses may be useful for investigating possibilities in the absence of knowledge..." In the case of magnetic phenomena the knowledge is not absent, so why to use hypotheses when the reality is known ? is my question ?94.113.59.212 (talk) 11:01, 14 September 2012 (UTC)

It is clear that you asserting
"monopoles simply *cannot exist at all* and that we *know the only reality* is electric currents/quantum spin is the source of all magnetism".
(*Applause!* Do you think anyone knows what "reality is" anyway? That's philosophy...). Does extensive, painstaking, searching in excruciating detail automatically "prove" that monopoles do not exist? No.
As Quondum pointed out with the electron-positron prediction from Dirac's equation, just because no positron's were found at the time does not automatically "prove" that they do not exist - they were found later. Same for monopoles. Who knows, in the next century, millennium or beyond (assuming Humanity lasts) that someday a monopole is found? What then?
I withdraw from this thread... Maschen (talk) 11:20, 14 September 2012 (UTC)

I withdraw from this thread...(Maschen). So do I.(94.113.59.212 (talk) 08:51, 15 September 2012 (UTC)) Such a "discussion" leads nowhere.94.113.59.212 (talk) 13:41, 14 September 2012 (UTC)

I recommend to read also the discussion to the article Magnetischer monopol Ich empfehle auch die Disskusion : Magbetischer Monopol zu lesen.94.113.59.212 (talk) 14:05, 14 September 2012 (UTC)

I strongly disagree with the assertion that "magnetic monopoles do not exist" and that they are a "misleading technical term". I agree,we have not found them,many suspect they dont exist,the difficultly in finding them seems to indicate they may not exist,perhaps even they probably dont exist. All of those might be valid statements,but we dont KNOW they dont exist,until for instance,someone finds a charge thats not quantized like it should be. If charges there are magnetic monopoles,then charges have to be quantized in a certain way,therefore if charges are NOT always quantized that way,there must not be any monopoles. No one has found that charge yet either. Finding either that charge or a magnetic monopole gets you a nobel prize,but so far,we just dont KNOW,all we know is that if there ARE magnetic monopoles,they are hard to find. As for it being a misleading technical term,far from it. You might try to say the same thing about the vector potential. But in fact,like monopoles,the vector potential is a very useful thing when solving problems. Similarly,you can solve magnetic field problems by positing monopoles.In the end though,it turns out the vector potential IS physical,as it can affect a particle in places where its curl vanishes. Makes me a little less certain about the monopoles. — Preceding unsigned comment added by 67.2.240.140 (talk) 07:59, 13 September 2013 (UTC)

## Covariant form of Maxwell's monopole equations?

Here [1] is a paper (and here [2] are more related) on the covariant form of Maxwell's equations including monopoles (it's not hard to imagine a monopole 4-current and find a second inhomogeneous equation from the Faraday and electric Gauss equations for monopoles, though obviously OR without citations). The equations are:

${\displaystyle \partial _{\mu }F^{\mu \nu }=\beta J_{\mathrm {electric} }^{\nu }}$
${\displaystyle \partial _{\mu }\star F^{\mu \nu }={\frac {\beta }{\gamma c}}J_{\mathrm {magnetic} }^{\nu }}$
${\displaystyle \star F^{\mu \nu }=G^{\mu \nu }}$

in more detail the vector set is:

${\displaystyle \nabla \cdot \mathbf {E} =\alpha \rho _{\mathrm {electric} }}$
${\displaystyle \nabla \cdot \mathbf {B} ={\frac {\beta }{\gamma }}\rho _{\mathrm {magnetic} }}$
${\displaystyle \nabla \times \mathbf {E} +\gamma {\frac {\partial \mathbf {B} }{\partial t}}=-\beta \mathbf {J} _{\mathrm {magnetic} }}$
${\displaystyle \nabla \times \mathbf {B} -{\frac {\beta }{\alpha }}{\frac {\partial \mathbf {E} }{\partial t}}=\beta \mathbf {J} _{\mathrm {electric} }}$

where:

Units α β γ
SI 1/ε0 μ0 1
Gaussian 4π/c 1/c
Heaviside-Lorentz 1 1/c 1/c

Any objections to inclusion (aside from those who think monopoles are "impossible"!)? Of course we can change the notation for α, β, γ to something less confusing with notation for the Lorentz factor... Maschen (talk) 06:41, 22 September 2012 (UTC)

The standard vector form (the second set of equations) is already adequately covered. The tensor form may be of interest, but to try and accommodate all systems of units is rather clumsy. — Quondum 11:14, 22 September 2012 (UTC)
The tensor (covariant) form is what I was emphasizing - obviously the vector equations are included in the article. We can just use the Gaussian and SI units for the appropriate sections, as you suggest. Maschen (talk) 11:27, 22 September 2012 (UTC)

Can you please explain how this contribution: "== Covariant form of Maxwell's monopole equations? == can help to explain the question of existence or non-existence of "magnetic monopoles?94.113.59.212 (talk) 13:07, 24 September 2012 (UTC)

It cannot. It is merely a mathematically equivalent rephrasing of existing formulae. — Quondum 13:49, 24 September 2012 (UTC)
Yes - exactly as Quondum says; the proposal here is for those interested in the covariant form of Maxwell's monopole equations, for use in special relativity for instance. They "explain/question/prove" nothing and no intension is made to do so. Maschen (talk) 18:07, 24 September 2012 (UTC)

## New section: Duality transformation

Very nicely done (by ‎Sbyrnes321), but there seems to be no mention of the U(1) symmetry, if that is the symmetry group... Also maybe it could be a 2nd level section? Maschen (talk) 19:36, 24 September 2012 (UTC)

If it's ok I will align the formulae. Maschen (talk) 19:39, 24 September 2012 (UTC)

## Proven Existence in Modern Physics

I've never worked this before, so I apologize beforehand if I mess this up. I've found these two intriguing articles and moves magnetic monopoles into the realm of reality (albeit not a very practically useful one at present; still better than hypothetical). I'm not qualified to provide any real text submissions/editions to Wikipedia, so if someone would be kind enough to appropriately create and word the new section, it'd be appreciated.

http://www.nature.com/news/2009/090903/full/news.2009.881.html http://www.sciencedaily.com/releases/2009/09/090903163725.htm http://arxiv.org/abs/0908.3568v2 — Preceding unsigned comment added by 111.68.108.82 (talk) 05:02, 1 March 2013 (UTC)

I can't find those articles you link to above in the references (may have missed), but spin ices are already discussed in this section and linked to. I'll put these links in the external links section. Thanks, M∧Ŝc2ħεИτlk 10:32, 1 March 2013 (UTC)

"Nearly 85 years after pioneering theoretical physicist Paul Dirac predicted the possibility of their existence, an international collaboration led by Amherst College Physics Professor David S. Hall '91 and Aalto University (Finland) Academy Research Fellow Mikko Möttönen has created, identified and photographed synthetic magnetic monopoles in Hall's laboratory on the Amherst campus. The groundbreaking accomplishment paves the way for the detection of the particles in nature, which would be a revolutionary development comparable to the discovery of the electron." http://phys.org/news/2014-01-physicists-synthetic-magnetic-monopole-years.html Thangalin (talk) 10:17, 30 January 2014 (UTC)

@Thangalin -- The "detection of the particle in nature" is what this wikipedia article is about, and it hasn't happened yet. The David Hall work is not it. Otherwise they would have said "the accomplishment is a revolutionary development comparable to the discovery of the electron..." rather than saying "the accomplishment paves the way for..." (And by the way, "paves the way for" is actually a euphemism for "does not make any progress towards".) The David Hall article is quite deceptive, and the press is gullible ... See discussion below. --Steve (talk) 17:24, 31 January 2014 (UTC)

## New monopole demonstration videos

Here we have a demonstration of monopoles being created; and here is a more thorough demonstration of their monopole nature (a compass is circulated completely around the object, showing that it has only a south pole and no north).

Is it the opinion of the editors of this article that these videos are a hoax? 71.219.201.182 (talk) 20:59, 18 May 2013 (UTC)

It must be a hoax, as no "magnetic monopoles" do exist ! I shall try to find out where the dupery is. 62.245.107.32 (talk) 13:30, 13 July 2013 (UTC)

The video seemingly demonstrating the "creation south poles" on one drip tray, and "north poles" on the other by passing the drops of melted metal through two coils of wire is nothing but fake abusing the visual similarity with Lord Kelvin Generator (see Wikipedia). Prove of the fake: 1. In "the demonstration" video no connection of the coils to electric current source is shown, so no magnetic field which should influence the melted metal passing through the coils exists. 2. The fact, that the needle of the compass when moved under the tray points always in the direction to the tray is no proof of "monopole". Such an effect has a small permanent magnet pasted to the bottom underneath the tray.(notice, that the compass was moved only under the tray, not also above it, where the magnetic field has opposite direction). The video is nothing but poor fake.62.245.107.32 (talk) 07:05, 14 July 2013 (UTC)

## In popular culture

Many years ago this article had an "In popular culture" section. It was entirely deleted, which is a pretty common fate for these kinds of sections -- See WP:POPCULTURE! But now it has been recreated and is steadily growing.

For what it's worth, here is the old version, immediately before it was deleted: [3].

I personally think that these sections can be nice when they are done well (not a list), but they tend to get flooded with trivia, and it's so much trouble to maintain that it's better to delete the section altogether. --Steve (talk) 17:11, 12 November 2013 (UTC)

It has been deleted. M∧Ŝc2ħεИτlk 21:09, 5 January 2014 (UTC)

## Discovery

The new paper is: Observation of Dirac monopoles in a synthetic magnetic field

in Nature

This is just... they exist?? arghhhhhhhh — Preceding unsigned comment added by Waylah (talkcontribs) 14:11, 30 January 2014 (UTC)

Magnetic monopoles can theoretically be of two types: having electric charge, or not having electric charge. It would be good to clarify which kind the recently-discovered ones are.Anythingyouwant (talk) 17:17, 30 January 2014 (UTC)
No, they don't exist, not as particles. The discovery of a true magnetic monopole would be a news event no less significant than that of the Higgs boson. —Quondum 05:54, 31 January 2014 (UTC)
The Nature paper set up a chamber full of protons, neutrons, electrons, photons. They did not discover any new elementary particle besides those. The press descriptions from this paper are extremely misleading, bordering on dishonest. --Steve (talk) 13:38, 31 January 2014 (UTC)
In the article is clear that authors used superfluid helium, not BEC condensed matter and surely not decoupled protons, neutrons and electron. Furthermore in the presentation there is a clear phrase: "These real-space images provide conclusive and long-awaited experimental evidence of the existence of Dirac monopoles". The question is only "are they right"? --Pippo skaio (talk) 16:04, 31 January 2014 (UTC)
The paper is shamelessly sensationalist in its description. I am surprised (and disgusted) that Nature published the paper without demanding a rewording. It is not only the popular press at fault here. Read the text carefully: they do make it clear that no actual fundamental particles were created, and no true monopoles created. There is nothing new over the spin ice "magnetic monopole", except that the medium and detailed mechanism is different. So, if you are asking about whether they are right about discovering what physicists refer to as a magnetic monopole, i.e. what is described in this article (i.e. Magnetic monopole), the answer is a very clear "no". —Quondum 16:26, 31 January 2014 (UTC)
Pippo -- I never said the protons, neutrons and electrons were "decoupled" -- obviously they are interacting with each other!! I just said that there are not other elementary particles in the chamber besides those (plus photons, gluons, gravitons, etc.). I was wrong before: It is not just the press release that is deceptive, but also the paper itself. You can find more clarity by reading Nature's own description of this article, in the very same issue. The title is "Quantum cloud simulates magnetic monopole" not "Quantum cloud contains magnetic monopole". Quote from the article: ""There’s a mathematical analogy here, a neat and beautiful one. But they’re not magnetic monopoles," Bramwell says. "You have to do a sideways jump — a bit of lateral thinking in your mind — to project these onto magnetic monopoles,"" --Steve (talk) 17:07, 31 January 2014 (UTC)

## Domains?

Should the article perhaps contain a brief explanation of why monopoles are not possible within normal matter? Perhaps with reference to magnetic domains, and/or to magnetic moment as an extensive property? (Please forgive any vocabulary glitches; my degree is in chemistry, not physics) DS (talk) 14:57, 18 February 2014 (UTC)

It sounds like you're discussing this section...
I don't understand the relevance of magnetic domains. A single-domain magnet is not a monopole, and a multi-domain magnet is not a monopole either.
I don't understand the relevance of "Magnetic moment as an extensive property". Magnetic moment is short for magnetic dipole moment, which is irrelevant because the issue under discussion is magnetic monopoles not dipoles. Right?
I guess it could be worthwhile to say something like "As with electric charge, the magnetic charge of a system is the sum of the magnetic charges of its component particles, i.e. all the electrons and protons etc. in the system. Since the magnetic charge of each of those particles is zero, the magnetic charge of any system made of ordinary matter is zero." That sort of discusses extensive-ness but I don't know if that's what you had in mind... --Steve (talk) 15:51, 18 February 2014 (UTC)
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