All matter, from stars to humans, is built from particles that in the Standard Model are divided into two families. But there's a third, rare kind — particles that, when swapped, don't just exchange places but tie themselves into a knot, remembering the intertwining rather than the path.
In the new experiment, they built a microchip from materials where current flows without loss and a special insulator that conducts only at the edge. At its ends, they managed to create Majorana zero modes — particles that are their own antiparticles. The researchers moved them along a tricky trajectory and recorded an energy change that matched theory exactly. So for the first time, they saw a quantum knot being tied.
The idea of a quantum computer was proposed by Richard Feynman, and John Preskill emphasized the importance of such protection. The next step is to weave trajectories into full-fledged knots. And an unexpected twist: these same particles might be lurking behind dark matter and resonate with the theory of black holes.
Majorana particles can be their own antiparticles: when two meet, they annihilate, even though normally a particle-antiparticle pair is required.