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So what exactly is a Weyl fermion? Although we're often taught in high school science that the Universe is made up of atoms, from a particle physics point of view, everything is actually made up of fermions and bosons. Put very simply, fermions are the building blocks that make up all matter, such as electrons, and bosons are the things that carry force, such as photons.
Electrons are the backbone of today's electronics, and while they carry charge pretty well, they also have the tendency to bounce into each other and scatter, losing energy and producing heat. But back in 1929, a German physicist called Hermann Weyl theorised that a massless fermion must exist, that could carry charge far more efficiently than regular electrons.
And now the team at Princeton has shown that they do indeed exist. In fact, they've shown that in a test medium, Weyl electrons can carry charge at least 1,000 times faster than electrons in ordinary semiconductors, and twice as fast as inside wonder-material graphene.
Most notably, it might we be possible to build better ways to produce them en masse for further study. The strange monopole arrangement they express is still puzzling scientists, but applications may abound:
What's particularly cool about the discovery is that the researchers found the Weyl fermion in a synthetic crystal in the lab, unlike most other particle discoveries, such as the famous Higgs boson, which are only observed in the aftermath of particle collisions. This means that the research is easily reproducible, and scientists will be able to immediately begin figuring out how to use the Weyl fermion in electronics.
(Score: 5, Interesting) by Anonymous Coward on Monday July 27 2015, @04:42PM
Because while it may be a quasiparticle it behaves exactly as would a "physical" particle. It's the same concept as a phonon, which is a quasiparticle of acoustic oscillation. It acts within the medium in very many ways as does a photon in vacuum (and given the situation acts *exactly* as does a photon). The only difference is that the "physical" particle is obeying a "fundamental" quantum field theory, while the quasiparticle is obeying what's known as an effective field theory, a quantised version of the field theory of a structure - it's a quantum description of the *statistical* theory describing the structure, as opposed to the Schroedinger equations of the individual components. The form of these effective field theories can be very close to, or identical to, the "physical" ones.
An interesting example close to my heart is the array of quasiparticles that can be excited in superfluid helium IIA. Perhaps 15-20 years ago, Grisha Volovik demonstrated that the quasiparticles in this particular form of Helium obey an effective field theory that *exactly* mirrors the standard model of particle physics, *plus a massless graviton*. If we could make a helium droplet big enough, beings could emerge in it that would see a physics with exactly the symmetries that we see.
(Where it falls apart is that the dynamics is different. Of course it is; the helium droplet is highly non-relativistic and is obeying ultimately a system of Schroedinger equations. But all the symmetries are there. And it's possible to imagine setups where you can also find the dynamics emerging, at least to lower orders in some expansion parameter. One guy - McElrath - claims to have found such a system emerging in the mixing of neutrinos and anti-neutrinos.)
Anyway, getting off the point. The point is that quasiparticles act exactly as particles do, except that they're confined to their medium and if the medium is driven out of a range of validity (if it gets too warm, for instance, and thermal fluctuations cause the quantum system to become decoherent). So if we can reliably and cheaply produce this kind of system it could, at least in principle, find application.
--boristhespider
(Score: 0) by Anonymous Coward on Monday July 27 2015, @05:20PM
As usual boris, thanks for providing some context.
(Score: 3, Interesting) by boristhespider on Monday July 27 2015, @06:26PM
No problem - it's well away from my field of expertise but I did do my Masters on acoustic black holes so at least I was reasonably familiar with quasiparticles and emergent physics at one point.