Physicist Leo Kouwenhoven ended a 75-year hunt for the tricky Majorana fermion – a particle that is its own antiparticle – by creating one on a chip
What is a Majorana fermion?
It is named for the physicist Ettore Majorana, who found that a particle could be its own antiparticle. If a particle has properties with values unequal to zero, then its antiparticle has the opposite values. What that means is that all the properties of a Majorana fermion, the charge, energy, what have you, it's all zero. It is a particle, but it doesn't have properties that we can measure. That makes it very mysterious. It also makes it difficult to find.