Fractional statistics in anyon collisions
Looking for intermediate statistics Elementary particles in three dimensions are either bosons or fermions, depending on their spin. In two dimensions, it is in principle possible to have particles that lie somewhere in between, but detecting the statistics of these so-called anyons directly is tricky. Bartolomei et al. built a collider of anyons in a two-dimensional electron gas of GaAs/AlGaAs (see the Perspective by Feldman). Two beams of anyons collided at a beam splitter and then exited the device at two outputs. The researchers studied the correlations of current fluctuations at the outputs, which revealed signatures of anyonic statistics. Science, this issue p. 173; see also p. 131 Correlations of current fluctuations in an anyonic collider reveal exotic statistics. Two-dimensional systems can host exotic particles called anyons whose quantum statistics are neither bosonic nor fermionic. For example, the elementary excitations of the fractional quantum Hall effect at filling factor ν = 1/m (where m is an odd integer) have been predicted to obey Abelian fractional statistics, with a phase ϕ associated with the exchange of two particles equal to π/m. However, despite numerous experimental attempts, clear signatures of fractional statistics have remained elusive. We experimentally demonstrate Abelian fractional statistics at filling factor ν = ⅓ by measuring the current correlations resulting from the collision between anyons at a beamsplitter. By analyzing their dependence on the anyon current impinging on the splitter and comparing with recent theoretical models, we extract ϕ = π/3, in agreement with predictions.