This is another one of those instances where I don't quite get what's going on, but I know enough to realize it's something I maybe ought to pass along.
Are you familiar with the basic idea behind matter and antimatter? The most recent question on Randall Munroe's comic What If? deals with that, so it may have been on your mind lately. The idea, if you know nothing else about it, is that we're all made of matter, and there's antimatter scattered in bits and pieces around the universe, and when matter and antimatter meet, they destroy each other. Okay, well, 'destroyed' isn't the word that gets used in that situation. The word you're supposed to use is 'annihilated', which is science-speak for ultra super duper destroyed. There is just plain nothing left afterwards, except for some gamma radiation.
So they don't get along. However, back in 1937, a scientist named Ettore Majorana theorized that a particle existed, somewhere, somehow, that could take on the properties of both matter and antimatter without going Hamster Huey and the Gooey Kablooie. This particle would eventually become known, fittingly, as a Majorana fermion. Now all that was left to do was go find it.
77 years later, a team at Princeton thinks they've found it. Reading the process for doing so, I quickly run into explanations that get over my head (and the $20 paywall for the original doesn't help), but it appears to involve a magnetic wire made of iron and a lead surface in a superconductor (which has no magnetic field). There's a string of electrons, most of which pair up so that there's one electron and one anti-electron, except for one guy at the end that can't get a dance partner and winds up exhibiting qualities of both. That's your Majorana fermion, or at least, that's what Princeton thinks is a Majorana fermion.
I am probably mangling this. Please click the links so you can see how much I'm leaving out and how much of an idiot I must look like right now.