Skyrmion?

[DarkStar7]

http://en.m.wikipedia.org/wiki/Skyrmion

Does any one understand this stuff?

[acey]

Agreed, the article is overly technical (hence the Wikipedia request for a rewrite).

Skyrmions are theoretical particles that arise topologically in certain field theories. Think of it like this: you've got a flat plane, and you've got threads running up from every point on that plane. The plane represents physical space(-time) and those threads (their length, orientation, whatever) define a "field".

The threads could all run vertically straight up: that's topologically trivial. Or they could get twisted together and kinked up - that's non-trivial. A skyrmion corresponds to a non-trivial topology. Some knots just fall out when you give them a shake, others stay kinked: they're stable. A skyrmion is stable, and could even move around (which stretches my analogy to breaking point but there you go).

Skyrmions first arose in the context of particular field theories (e.g, something called the non-linear sigma model) which may or may not describe actual existing things, but which physicists use as a way of investigating different possibilities (the non-linear sigma model in fact turns up in superstring theory, which may or may not have something to do with the real world).

Skyrmions have never been observed as fundamental particles (so Tony Skyrme, like Peter Higgs, is still waiting for that phone call...). But solid-state physicists have observed skyrmions in the form of stable topological defects in crystals: specifically as localised alignment of magnetic spins to form a stable pattern that could have practical applications. See these links:

First direct observation of unusual magnetic structure could lead to novel electronic, magnetic memory devices

World?s First Successful Direct Observation of ?Vortex-shaped Spin Texture: Skyrmion Crystal? - 2010 | NIMS

http://www.nature.com/nature/journal/v465/n7300/full/nature09124.html

[DarkStar7]

Cheers Acey,

I believe that a lot of Gauge theories descriptions are closer to reality than particle theories. I think when students are taut particle physics they should be shown how it compares with a gauge theory description of the same phenomena. For example most people view the atom in the classic solar system model rather than visualising elliptical atomic orbitals around a central nucleus. The solar system model makes it simple but misleading.

Many thanks for your reply Acey