OT - Existance of a Magnetic Monopole

No. There will be symmetry of magnetism for any observable particle. "symmetry" means "both poles."

There might be a trick as physics progresses, but we don't know what that means now. Can't prove it, but I believe a manifested magnetic monopole violates the laws of thermo ( the second? ).

Particles ain't points. They at least have nonzero radii.

-- Les Cargill

Back when the existence of a magnetic monopole obsessed physicists, the mm was thought to BE a particle. But that was back in the 70s and early 80s.

here's something interesting and relatively current: (Scroll down to magnetic monopole)

Yes...an electrical monopole.

Why would you think so?

No can do; charge is conserved. Charged particles are always created/ annihilated in pairs, positive and negative, before and after equal sum to zero. Positively charged "daughter" particles result from the decay of other positively charged particles.

A magnetic monopole only makes sense as a mathematical trick. Magnetic poles are emergent effects of charge + spin. Since spin always has two poles, so do the magnetic fields of charged particles.

BTW, why are you asking this in SED?

Mark L. Fergerson

Then again, spin, antimatter, and a host of other things (up to the most recent Higgs discovery) were discovered as "mathematical tricks" that just happened to turn up in the abstract equations.

Maxwell's equations, relativity and QED are three of the most well established, accurate and practical theoretical frameworks. Many effects were predicted by these theories before discovery by experiement.

If a theory says monopoles can exist, who's to say they can't? There might even be no physical mechanism to create them, but inability to produce something that's possible is not equal to something that's impossible outright.

Tim

Ball Lightning.

They just don't last long before they get pulled back into the dimension where they are otherwise hidden from us.

ts

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I always figured that if there are MM's then they come in both polarities and get bound up into magnetic 'atoms'. So there is no external magnetic field to see. If the binding energy is really large then there won't be very many 'ionized' magnetic 'atoms'.

George H.

the most scientifically intelligent group I subscribe to

You are assuming physics where charge is not conserved?

I seem to recall that magnetic monopoles are allowed theoretically even when charge is conserved (ie. monopoles are consistent with Maxwell's equations), and their non-existence is an experimental observation. Hence the term div B has been set to zero in M E's.

I guess what you are trying to ask is: if the continuity equation d rho / dt =3D - div J is discarded, does the consistency require that div B must be nonzero?

Regards, Mikko

Proposition: MM haven't been observed because they are very massive (>200GeV?). Suppose: MM exist in roughly equal proportion, so they tend to bind together (as above). Suppose further that they interact primarily through the electromagnetic force (antiparticles can annihilate into gammas, and atomic orbits interact analogous to Coulomb-potential atoms such as hydrogen).

Since no other magnetically charged particles exist (or if they do, they are subsets of MM matter (MMM), unrelated to known particles), MM of opposite charge will form hydrogenic atoms (and potentially, molecules, even extended structures), but due to the very high mass, the binding energy is extremely large, and physical size extremely small (much smaller than a proton for the whole thing).

- Instead of electron mass, use the reduced mass: m_0 = (m_MM+ * m_MM-) / (m_MM+ + m_MM-) Where m_MM+ is the mass of the positive charged particle, and m_MM- the negative. If the particles are equal, the reduced mass is simply m_MM / 2, or over 100GeV/c^2 under present assumptions.

- Instead of e_0 we use mu_0, and instead of e, we use q_m = h / e =

The resulting form: (m_MM / 2) * q_m^4 / (8 * mu_0^2 * h^2) = m_MM * h^2 / (16 * e^4 * mu_0^2)

However, the coefficient on mass (the h^2/(8*e^4*mu_0^2) part) is 586 c^2, in other words, it represents an ultrarelativistic ground state energy level -- a state in which the atom is unlikely to remain stable! The RME (rest mass energy) is passed below approximately n = 12 (i.e., on the transition from quantum number n=12 to n=11), so that whatever quanta of energy is given off, presumably, could pretty well obliterate whatever a MM is made of.

- So hey, that's pretty cool! A classical atom of "monopolium" is most likely impossible by a large margin, because its ground state contains far more energy than the particles themselves do -- independent of the actual mass of the particles participating. This means, in general, that a magnetic "atom" is impossible, by nature of the force itself. In contrast, electric forces allow for stable quantum atoms with well defined ground states.

Tim

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Hi Tim, I'm not quite following that last bit. I get the feeling that you're a lot smarter than I am... so no worries.

Here's a semi-crazy thought. Let's say (contrary to your supposition) that MM atoms do exist. But they are bound so tight we can=92t see them. (sounds a bit like dark matter.) However if they are similar to normal atoms, then they should have a permanent electric dipole moment! And in a static electric field we could tickle them with a resonant changing electric field and see the little buggers. (The converse of NMR)

George H.

I know enough physics to be dangerous. Fortunately, the field is mostly just mashing together physical constants until you get a quantity with the correct units. (Most physics problems actually work out this way, though more rigorously of course!)

In short: substituting the magnetic force for electric in the hydrogen atom, you get something that's probably impossible -- the energy of the ground state is vastly greater than that of the particles interacting.

Indeed! The probably very small atom thus formed might have a vanishingly small moment, but it may still be detectable (ppt or less, versus the ppm signal NMR typically generates). If you could trap these in a hunk of dielectric (or vacuum), it would be easy to pick up their oscillations inside an electric field (assuming they stick around long enough to interact).

Now, the Larmor frequency of magnetic moments is omega = e*g*B / (2*m), so one would expect omega = q_m*g*D / (2*m), where D is the displacement field (C/m^2, contrast with B in units of Wb/m^2), and q_m is still h/e (in Wb, instead of e in units of C).

The hard part is g, the g-factor, "dimensionless magnetic moment". To guess further, we'd have to know the 'gyroelectric' constant instead.

In the end, I'd like to guess how the electric dipole compares to the magnetic, and figure if its amplitude and frequency are within reach.

Tim

why do you search for magnetic monopoles? You have to first prove they exist.

None of the existing theories allow for a magnetic monopole:

I would address your work to proving all prior work is flawed, and showing where the errors lay.

At the end, you must conceive of a particle that spews a positive or negative magnetic field, that terminates on nothing.

Good luck on that.

Regards,

Mike

How is that any more absurd than a particle that spews a positive or negative electric field that terminates on nothing?

Maxwell's equations can be trivially modified to allow for this symmetry, so don't use del . B = 0 as an excuse.

Tim

-- Deep Friar: a very philosophical monk. Website:

You can take an ordinary hydrogen atom and separate the electron from the nucleus. The electron has a negative charge. The proton has a positive charge. An electrostatic field exists between them.

Separate the electron to infinity. The electrostatic field remains. It has no limit. It is produced by two physical objects that you can separate and move around.

You can also take a conductor. It has a measurable capacitance to the rest of the universe. In a physical world, the capacitance would be with respect to the closest conductor, most likely ground.

You can put a positive or a negative charge on the conductor. This will produce a voltage with respect to ground that you can measure. The voltage is caused by a surplus or deficiency of electrons. The field is static. It will remain as long as there is no leakage.

Now consider a permanent magnet. The magnetic field is caused by the alignment of electron spins. It has a positive pole and a negative pole. There is no way you can remove one pole to infinity. They are part of the same field.

Consider current in a conductor. A magnetic field exists around the conductor. The right hand rule shows which direction points north.

There is no way you can split the field into two poles and separate them. Unlike the electrostatic field, the magnetic field is circular and doesn't have individual components that can be separated.

You can form the conductor into a solenoid. The magnetic field goes through the center of the solenoid, as in this image from Wikipedia:

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Again, there are no magnetic poles you can separate and move around. But if you insert a steel rod in the solenoid, you can say that one end will be the north pole, and the other end the south pole.

But the poles do not exist. They cannot be separated.

Regards,

Mike

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OK, You still have to guess what the mass scale is. I guess we can assume it's greater than whatever the Fermi accelerator (an maybe the LHC) can see, else they would have perhaps found something. Anyway I don't think that having a binding energy greater than the self energy of the particles is impossible.

gly

Yeah I think the hard part of searching for something unknown like this is where do you look.

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I think I should be able to guesstimate the size of the monopole electric dipole moment from fundamental physics.... like the electron magnetic moment. But again I need a mass.... (We'll just set g =3D 2, that should be close enough)

Maybe I can try crunching some numbers this weekend. (I gotta get a new water pump into the backhoe, that's a priority.)

George H.

Hi Mike, I don't know how you would prove they existed, before you found one.

But if you did find one you'd be famous... guaranteed nobel prize, physics chicks dripping off your arms... (Maybe that wouldn't be such a good thing though.)

Anyway it=92s fun to speculate.

George H.

Read down that page.. It's real easy to put MM's into Maxwells equations.

I don't know of any fundamental physics that says MM's can't exist. It's just that no one has seen one, so there's no reason to stick one into the theory.

George H.

This is the magnetic result of an electric entity. Moving (or spinning) charge makes a magnetic dipole. You can't put a magnetic charge on a hunk of metal because metals are made of electrons, not MMM.

If a MM were the same mass as the electron (and a couple of other considerations, as I noted, like the ground state energy), one would have MMM identical to the electric stuff. The atoms would have electric dipole moments resulting from the flow (spin, orbit, etc.) of magnetic charge. A hunk of the stuff could become magnetically charged, in the same way regular matter picks up static.

You could make an electric transformer out of MMM metals. A "ferromagnetic" material built of MMM would have extremely high permittivity; a "ferroelectric" material would likewise have very high permeability (both effects being aspects of a similar phenomenon; implementing them in MMM would simply fill out the symmetry).

None of this is prohibited by classical physics -- besides the QM arguments I've been making, I think you're going to have to dig into QED at least to find a more certain answer, one way or another. And apparently, the newest physics (QCD, SSy and beyond) are still on the fence, and for the last two centuries, the only good reason not to believe in them is, simply, we haven't seen them yet!

Tim

Can you describe what the field would look like in a MM?

Where would the lines terminate?

How would you make a MM of the opposite polarity?

You can do all these things with electrostatics. There are positive and negative charges. You can separate them without violating conservation laws. The field starts at one object and terminates at the other. They have a definite beginning and ending.

I think the nature of a magnetic field prohibits a MM. The field lines pass through the source and wrap around so they are continuous. There is no starting and ending point like electrostatic fields.

If you cannot have a definite starting and ending point, you cannot have positive or negative poles. If you cannot have separate poles, you cannot have a MM.

Show me how the field would look.

Regards,

Mike