Magnetic Monopoles Detected?

http://www.sciencedaily.com/releases/2009/09/090903163725.htm

by jperras • 17 years ago

29 8 17 years ago

fhars• 17 years ago

It is a quasi particle that results from the collective state of electrons in solid matter. It is not really a monopole, since it is necessarily connected by a flux tube (no Back to the Future jokes, please) to an opposite pole. If you integrate the flux over a closed sphere, you still get a total flux of zero. Only if you leave a small hole where the flux tube leaves the sphere around your "pole" you get something that looks like a monopole, with things like the inverse distance behaviour you see for electric and gravitational fields.

This is similar to the field you see near the ends of strong long and thin conventional magnets (where the matter of the magnet plays the role of the flux tube).

So this is a very interesting discovery in the field of solid state physics, but any connections to elementary particle physics you might think of when you hear about the discovery of a magnetic monopole are wrong.

wwalker3• 17 years ago

The investigators themselves are slightly more temperate than Science Daily. They used the name "classical magnetic monopoles" in a presentation a couple of years back (http://www-thphys.physics.ox.ac.uk/people/ClaudioCastelnovo/...), and explicitly said they're not elementary particles (though they did bury that bit towards the middle of the presentation).

jcdreads• 17 years ago

Right. Divergence of B is still zero.

Confusion• 17 years ago

However, the question is whether a 'real' magnetic monopole must necessarily be a fundamental particle. Perhaps this is one of the only ways in which the properties of a magnetic monopole manifest themselves.

lutorm• 17 years ago

You can't make a field with divergence out of divergenceless components, so no, it has to be something that's not in normal matter.

swombat• 17 years ago

One interesting use, I thought, of magnetic monopoles (whether they are fundamental particles or not), would be in the construction of a perpetual motion machine. If it is possible to manufacture these monopoles in a controlled manner, it could be possible to create a turbine that accelerates forever (thus generating free energy)... or am I missing something?

gjm11• 17 years ago

Either you are or I am. My guess is that you're assuming that you can manufacture unlimited quantities of these things without expending any energy to do so.

(If the existence of magnetic monopoles enables you to build a perpetual motion machine, why doesn't the (uncontroversial) existence of electric monopoles?)

antipaganda• 17 years ago

Or indeed gravitic monopoles.

Magnetic Monopoles Detected?

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