Big news! Scientists at TU Delft's Kavli Institute and the Foundation for Fundamental Research on Matter have detected a Marjorana particle for the very first time, causing "great excitement among scientists!" Woohoo! So what the heck is a Majorana fermion, anyway?
To explain this, we're going to have to start waaay back with elementary physics. When I say "elementary," I don't mean all that physics that you were learning back in first grade, but rather, thinking about some of the fundamentals of how our universe it put together.
In physics, there are two basic types of elementary particles: fermions, and bosons. Generally, fermions are particles that make up matter, like quarks and electrons, while bosons are particles that carry force, like photons.
The difference between the two comes down to the fact that bosons have integer units of spin (like zero or one), while fermions have non-integer spins (like 1/2). The word "spin" is misleading a little bit, in that the particles aren't actually spinning in the sense that we think of things like basketballs as spinning, but you can just think of it as a basic quantum characteristic that all elementary particles have. Photons, for example, have a spin of one, and they're bosons. Quarks and electrons have spins of 1/2, so they're all fermions. And the Higgs boson, when it shows up, will probably have a spin of zero.
The practical outcome of this difference is that fermions, with their non-integer spins, aren't able to share energy states with each other. So when you get a bunch of electrons together, they all have to go find their very own little private energy state, which is where those electron orbitals come from. Bosons, on the other hand, can share energy states, so under the right circumstances you can merge a big blob of them together into weird things like Bose-Einstein condensates.
So, What's A Majorana Fermion?
Now that you understand (I hope) what a fermion is, let's talk about this Majorana thing. The funny name comes from Ettore Majorana, an Italian mathematician and physicist whose idea it was. Essentially, a Majorana fermion is a particle that's its own anti-particle. Bear with me for a second here: you know how there's matter and antimatter, and when they come together they annihilate each other and release tons of energy and you get things like warp drives? Well, a Majorana fermion works just like that, except there's no "anti-." Instead, when two of them come together, they just annihilate right away.
It's possible that neutrinos are a type of Majorana fermion (we're not quite sure), but we do now know that these things actually exist.
Zee Germans der Nederlanders were able to generate a pair of them using an indium antemonide nanowire, covered with a gold contact and partially covered with a superconducting niobium contact, which (in retrospect) seems like a totally obvious way to go about doing it. Like, duh.
Besides a demonstration of the cleverness of
zee Germans der Nederlanders, what's the point of a Majorana fermion? There's just one big thing, really: quantum computing. Unlike the quantum computers we've got right now, which are touchy little things, a quantum computer based on Majorana fermions would be "exceptionally stable and barely sensitive to external influences." Oh, and Majorana fermions may also be a part of all that dark matter stuff that's supposed to make up a big chunk of our universe, so they've got that going for them, too.