Physicists have reported what could be the first incontrovertible evidence for the existence of unusual particle-like objects called anyons, which were first proposed more than 40 years ago. Anyons are the latest addition to a growing family of phenomena called quasiparticles, which are not elementary particles, but are instead collective excitations of many electrons in solid devices. Their discovery made using a 2D electronic device-could represent the first steps towards making anyons the basis of future quantum computers. Anyons are even more strange. All elementary particles fall into one of two possible categories-fermions and bosons. Anyons are neither. The defining property of fermions (which include electrons) is Fermi statistics: when two identical fermions switch spatial positions, their quantum-mechanical wave—the wavefunction—is rotated by 180º. When bosons exchange places, their wave doesn’t change. Switching two anyons should produce a rotation by some intermediate angle, an effect called fractional statistics that cannot occur in 3D space, but only as collective states of electrons confined to move in two dimensions.
Fractional statistics is the defining property of anyons. Physicists manifactured a structure of consisting thin structure of Gallium Arsenide and Alumnium Gallium Arsenide to observe the defining property that they accumulate a fractional phase when one anyon travels around another. Moving anyons had two possible paths, each producing a different twist in their quantam-mechanical waves, when the anyons reached the end point, their quantam-mechanical waves produce an voltage and the magnetic field strength. But the interference also displayed Jumps, which are the smoking gun for the appearance or disappearance of anyons in the bulk of the material. It is an extremely solid observation of anyons.
Some theoretical physicists say that the evidence in these and other experiments, although striking, was not conclusive.The results potentially lay the groundwork for applications for anyons. Others have developed elaborate theories that use anyons as the platform for quantum computers. Pairs of the quasiparticle could encode information in their memory of how they have circled around one another. And because the fractional statistics is ‘topological’—it depends on the number of times one anyon went around another, and not on slight changes to its path—it is unaffected by tiny perturbations. This robustness could make topological quantum computers easier to scale up than are current quantum-computing technologies, which are error-prone. Microsoft has been alone in pursuing the topology path for quantum computing, whereas other large companies, including IBM, Intel, Google and Honeywell, have invested in alternative approaches.
But Topological quantum computing will require more-sophisticated anyons. Still, anyon applications are some way off, researchers warn. Also the quasiparticles’ unique physics is worth exploring.