They used a powerful machine called a quantum processor to make, for the first time, a brand-new phase of matter called non-Abelian topological order. Previously recognized in theory only, the team demonstrated synthesis and control of exotic particles called non-Abelian anyons, which are neither bosons or fermions, but something in between. Anyons are quasiparticles in a two-dimensional space.
What's exciting is that they can be used to make a quantum computer that is much more stable than current efforts with superconducting qubits.