Magnetic Monopoles

[Rade]

I have a question...what is the status of the concept of 'magnetic monpoles' ?

 

It is my understanding that in introductory classes on physics it is taught they do not exist. Thanks for update on the topic. From the little I know, they were predicted by Paul Dirac years ago and thought to be perhaps as gauge particles---see below:

 

Dirac, P.A.M. 1931. Quantised singularities in the electromagnetic field. Proc. Roy. Soc. A133:60.

 

Montonen C, Olive D. 1977. Magnetic monopoles as gauge particles? Phys. Lett. 72B:117

[maddog]

I have a question...what is the status of the concept of 'magnetic monpoles' ?

 

It is my understanding that in introductory classes on physics it is taught they do not exist. Thanks for update on the topic. From the little I know, they were predicted by Paul Dirac years ago and thought to be perhaps as gauge particles---see below:

 

Dirac, P.A.M. 1931. Quantised singularities in the electromagnetic field. Proc. Roy. Soc. A133:60.

 

Montonen C, Olive D. 1977. Magnetic monopoles as gauge particles? Phys. Lett. 72B:117

Monopoles are still theoretically predicted in some models, yet have no physical evidence

in any observation or physical experiment to date. Supersymmetry models are where I

have seen the most recent discussion.

 

maddog

[Pyrotex]

A monopole detector is trivial to build. Just make a giant loop of conducting wire and attach it to a very sensitive current meter. A monopole going through the loop will create a tiny transient current spike. They've been built. No results that I know of.

[Rade]

Magnetic monopoles discovered:

 

Magnetic Monopoles Detected In A Real Magnet For The First Time

 

Edit: So a question. Given that all matter has antimatter potential (electron--positron; proton--antiproton, etc.) would this mean there are predicted both "matter magnetic monopoles" and "antimatter magnetic monopoles" ? And then, how exactly would they interact ?

[Pyrotex]

Magnetic monopoles discovered:...Edit: So a question. Given that all matter has antimatter potential (electron--positron; proton--antiproton, etc.) would this mean there are predicted both "matter magnetic monopoles" and "antimatter magnetic monopoles" ? And then, how exactly would they interact ?

 

Just talking off the top of my hat here. Monopoles would be their own "anti-particles". A "north" monopole would be the anti-particle of a "south" monopole and vice versa. However, when two opposite magnetic monopoles approach each other, they DO NOT cancel out or anihilate each other, as opposite charges would. They form a DIPOLE.

 

However, from what the article says, monopoles aren't "particles" like electrons and positrons. They aren't little "hunks of matter". And magnetism isn't really "like" electric charges. Electric fields ARE mediated by monopolic singular charges: electron, positron. Magnetic fields are mediated by DIPOLIC configurations of atomic nuclei that have a kind of "spin" (whatever that is :rolleyes:). Both north and south magnetic fields issue from opposite ends of this dipole configuration. Dipoles can "attach" to each other, forming arbitrarily long "super-dipole strings", just as a bunch of small magnets can attach forming a much bigger magnet.

 

What the article seems to indicate is that by combining magnetic dipoles in a unique crystal structure, the dipole strings can be made to cancel each other out, EXCEPT for the very ends, which appear and behave like a monopole source of either a north or south field. But that doesn't mean you could remove one of those "monopoles" all by itself.

[UncleAl]

A monopole detector is three orthogonal supercon circles each with its SQUID detector. Now you get single quatum detection plus trajectory. 60s-70s there were supercon loops with a Lionel train set going though. Load the hopper cars with candidate monopole "ores" and send them round and round. Dipole and higher multipoles cancel. Nothing anomalous was observed.

 

Magnetic monopole - Wikipedia, the free encyclopedia

If a single magnetic monopole is reliably detected, Maxwell's equations symmetrize.

 

--

Uncle Al

UNDER SATAN'S LEFT FOOT

Vote a 10 for doing the experiments!

[IDMclean]

Real-space observation of emergent magnetic monopoles and associated Dirac strings in artificial kagome spin ice

Scientists capture first direct images of theoretically predicted magnetic monopoles

 

Ha! Take that Maxwell!

[Qfwfq]

Ha! Take that Maxwell!

:umno:

 

Real Dirac strings are no contradiction of Maxwell.

 

For each pole there is an opposite one at the other end of the Dirac string. The flux along the string, from one pole to the other, equals that outside, going from the other to the one. The magnetic field is solenoidal. Even if the string goes out to infinity, so that the other pole "is infinity", the field is still solenoidal.

[Tormod]

Ha! Take that Maxwell!

 

Thanks for the links, IDM - I posted one of them as a news story here:

Scientists capture first direct images of theoretically predicted magnetic monopoles

[IDMclean]

:umno:

 

Real Dirac strings are no contradiction of Maxwell.

 

For each pole there is an opposite one at the other end of the Dirac string. The flux along the string, from one pole to the other, equals that outside, going from the other to the one. The magnetic field is solenoidal. Even if the string goes out to infinity, so that the other pole "is infinity", the field is still solenoidal.

I did not imply that it was contradicted. With the demonstration of monopoles, we know that at some point Dirac's corrections come into play which means Maxwell's equations are approximate without the corrections. Fun part is it implies quantization of the magnetic "charge".

[Qfwfq]

Well as far as I can tell you are making a muddle. A more appropriate way to state things is, the fact that electric charge is discrete implies the possibility of magnetic monopoles without requiring any correction to Maxwell's equations. This, at least, on paper (in the sense that it is mathematical trickery).

 

It should also be noted that the flux tubes of condensed matter systems are only analogous to the Dirac string, somewhat like the opposite charge carriers of semiconductors are only analogous to the Dirac "sea" model for the antiparticle. Would you seriously say that diodes and transistors are full of positrons?