Amherst Researchers Create Magnetic Monopoles

An anonymous reader writes "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." That's quite a step beyond detecting monopoles; the Nature abstract is online, but the full paper is paywalled.

This is cool, but

[Anonymous Coward]

they haven't really found a magnetic monopole. They've created a long skinny solenoid with ends that are far enough apart that they look like independent monopoles.

Great physics, terrible summary.

Re:Contradicts current theory?

[tibit]

That's some misunderstanding of what a scientific theory is, right there. A theory must have predictive power - it must be useful for something, that is. Electromagnetic theory, so far, is extremely successful precisely because it works where we need it to work. The monopole demonstration doesn't change it one iota - neither your computer nor your electric plant have stopped working overnight.

It doesn't matter in practice that it doesn't work everywhere, and there's no need to rewrite anything and there's no contradiction. We know that the classical theory of electromagnetism, well, applies to classical scale phenomena, under certain conditions. No scientist in their sane mind would insist that this effect contradicts the classical theory. It's simply outside of the classical theory's scope, just as relativistic effects are outside of the realm of classical mechanics.

The real problem is with extremely widespread, naive understanding of what a scientific theory is and that there are limits to applicability of any scientific theory of nature. The phrase "law of nature" is perhaps the biggest romanticism-imbued snafu there ever was in popularization of science.

Re:Monopole Magnets

[Kongming]

You ivory tower intellectuals must not lose touch with the world of industrial growth and hard currency. It is all very well and good to pursue these high-minded scientific theories, but research grants are expensive. You must justify your existence by providing not only knowledge but concrete and profitable applications as well.

"but the full paper is paywalled"

[Anonymous Coward]

Unless you are really up on your Maxwell's equations and condensed matter physics, you wouldn't get much out of the actual paper. When I hear all the bitching and moaning about paywalled papers and how "the people" need to see the paper, I can't help but think that 99.999% of "the people" couldn't get past the intro paragraph because of all the field-specific details. That's why there are places like Scientific American and numerous science-writer blogs to translate this for the layman. If you can understand the following, then you most likely have access to the actual article, and if you don't know what this all means, then you are far better off going for the layman's summary:

The spinor order parameter corresponding to the Dirac monopole14,17 is generated by an adiabatic spin rotation in response to a time-varying magnetic field, B(r, t). Similar spin rotations have been used to create multiply quantized vortices18 and skyrmion spin textures19. The order parameter Y(r, t)5y(r, t)f(r, t) is the product of a scalar order parameter, y, and a spinor, f~ðfz1,f0,f{1T¼^ jfi, where fm5Æmjfæ represents the mth spinor component along z. The condensate is initially spin-polarized along the z axis, that is, f5(1, 0, 0)T. Following the method introduced in ref. 14, a magnetic field Bðr,t~bqðxx^zy^y{2z^zzBzðt^z is applied, where bq.0 is the strength of a quadrupole field gradient and Bz(t) is a uniform bias field. The magnetic field zero is initially located on the z axis at z~Bzð0=(2bq)?Z, where Z is the axial Thomas–Fermi radius of the condensate. The spin rotation occurs as Bz is reduced, drawing the magnetic field zero into the region occupied by the superfluid.

Re:Pseudoparticles

[jeffb (2.718)]

I like the "electron hole" analogy. Electron holes aren't as spectacular as positrons; they don't annihilate electrons and generate gamma-ray photons. They can, however, "annihilate" an electron in a semiconductor to produce a visible photon -- and that's how we get LEDs.

This "monopole" won't let us build super-motors or disintegrate protons at will. But I wonder if, recreated in a more robust medium, it could have its own interesting uses?

Re:Contradicts current theory?

[wagnerrp]

Just like Einstein didn't make anything Newton discovered incorrect.

Of course he did. Newton's laws of motion are wrong, but they're still close enough for use in certain scales and applications. The small angle approximation is wrong, but it still lets you do some trig in your head. Truncating a series expansion after just a few orders is wrong, but that's often all you need.