The Majorana (quasi)particle

The discovery of the Higgs boson, the misnamed God Particle, has gotten a lot of attention.

But a few months ago an effect was confirmed that brings us back to one of this blog’s favorite characters: Ettore Majorana.

You remember the story of Majorana, right? No?

Fine, for all you kids with attention deficit, here it goes again (in summary mode):

Ettore Majorana was a young and brilliant Italian physicist, a disciple of Enrico Fermi, considered one of the most brilliant physicists of his time, admired by everyone, who vanished mysteriously on March 25, 1938, when he boarded a ship and was never heard from again. His ideas were so far ahead of their time that only some 20 years later did Nobel laureate Richard Feynmann rediscover and reformulate several of his ideas, so that the rest of the scientific community could understand them. Legend has it that he was seen in Argentina in the 50s, where he supposedly worked as a humble engineer. There are more mysterious details, which I wrote about in this post, so go and read it carefully. I’ll wait for you here.

(Pause so you can read about Majorana.….)

Good. It turns out this young scientist predicted the existence of a particle known as the Majorana fermion. In particle physics we have bosons and fermions. Fermions obey the Pauli exclusion principle, bosons don’t. This is a bit complicated and I’ll explain it another day, okay?

So, Majorana predicted that there must be a class of fermions with the peculiarity of being their own antiparticles (you know, electrons have an anti-electron, known as the positron; in the case of Majorana fermions the antiparticle is the particle itself). So far nobody has managed to find a Majorana fermion, although they suspect neutrinos might be one, which is a good excuse to keep using that monster of a machine we have at CERN, or to spend a few more billion euros on another one. We’ll see what happens... :)

Ah, but all of that is very complicated.

The important thing is that although no Majorana fermions have been found, quasiparticles with their properties have been produced in superconducting environments, which would make it possible to build quantum computers (not quirky, quantum).

And since I know this business of quirky quantum computers drives many of you crazy, I leave you this talk by Roman Lutchyn at Microsoft Research on Topological Quantum Computation using Majorana Fermions (holy smokes!)

This talk is from September 2011. In April 2012 the existence of these quasiparticles was verified, so this kind of computing is now feasible. It’s a matter of time...