Fractional statistics in anyon collisions

Abstract

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 $\nu=1/m$ (where m is an odd integer) have been predicted to obey abelian fractional statistics, with a phase $\varphi$ associated with the exchange of two particles equal to $\pi/m$. However, despite numerous experimental attempts, clear signatures of fractional statistics remain elusive. Here we experimentally demonstrate abelian fractional statistics at filling factor $\nu=1/3$ by measuring the current correlations resulting from the collision between anyons at a beam-splitter. By analyzing their dependence on the anyon current impinging on the splitter and comparing with recent theoretical models, we extract $\varphi=\pi/3$, in agreement with predictions.