via New Scientist
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.
Why hunt for these tricky particles? My background is quantum computing. Measurement is problematic for a quantum computer, because observation changes the quantum state. But if you don’t have an apparatus that can measure a Majorana fermion, you cannot change it.