Wednesday, July 29, 2015

Weyl Fermions

This is a bit late, but what they hey....

Here is another triumph out of condensed matter physics experiment. This is the first reported discovery of the Weyl fermions, first predicted and now found in a Tantalum arsenide compound.

Another solution of the Dirac equation – this time for massless particles – was derived in 1929 by the German mathematician Hermann Weyl. For some time it was thought that neutrinos were Weyl fermions, but now it looks almost certain that neutrinos have mass and are therefore not Weyl particles.

Now, a group headed by Zahid Hasan at Princeton University has found evidence that Weyl fermions exist as quasiparticles – collective excitations of electrons – in the semimetal tanatalum arsenide (TaAs).

For those who are keeping score, this means that these condensed matter systems have, so far, detected Majorana fermions, and analogous signatures of magnetic monopoles.

And many people still think condensed matter physics is all "applied" and not "fundamental"?


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