Physicists have long sought particles that are their own antiparticles — Majorana fermions. They were supposed to be perfect 'mirror twins', immune to interference. Such states were suspected in superconductors — materials where current flows without resistance. It was thought that 'braiding' their trajectories would protect a quantum computer from errors.

However, a rigorous proof shatters this mirror. In a system with a fixed number of particles, any excitation carries the same charge as ordinary electrons. These states are not mysterious twins, but the same old electron blobs. Even the theory of superconductivity by Bardeen, Cooper, and Schrieffer was originally built on pairs, not on solitary 'twins'.

Now not only quantum computing is in question, but the very completeness of superconductivity theory. Perhaps a new approach must be sought that wouldn't violate particle number conservation. This is also important for understanding superconductivity inside neutron stars. And attempts to create Majorana modes by heating or magnetic fields are akin to hoping to assemble a puzzle by shaking the box — chaos destroys the delicate order.