Crafting Anyons with Quantum Circuits – CRAQUANT

Anyons are entities that evade the standard classification of particles into bosons and fermions, as exchanging two of them leads to an arbitrary exchange phase for the two-body wavefunction that is neither 0 (bosons) or pi (fermions). They can exist in strongly interacting two-dimensional systems like two dimensional electron gases in the Fractional Quantum Hall regime. Indeed, low-energy excitations of this regime carry a fractional charge and possess fractional exchange statistics, i.e., are anyons. While fractional charges have been measured twenty-five years ago, a direct proof of anyonic statistics has been missing, until 2020 where two teams reported such evidence. However, the demanding experimental conditions, as well as the fragility against disorder of these fractional states, impedes a further quantitative understanding of anyons and possible extensions to more exotic, non-Abelian states that are relevant for topological quantum computing. I propose a novel approach where strong correlations are engineered to make anyonic statistics emerge in the much more accessible and robust Integer Quantum Hall regime. The central ingredient is a small Ohmic contact with high charging energy connected to N > 1 ballistic Quantum Hall channels. Any electron injected in such an island will be fractionalized, with pulses of charges e/N that leave the island through the outgoing ballistic channels. I plan to unravel the predicted fractional exchange phase of such excitations using electronic Mach-Zehnder interferometry in one of the outgoing channels. The quantum simulation of anyons in relaxed experimental conditions (lower magnetic field, robustness against sample-dependent disorder) will constitute a first, and will enable quantitative comparisons between theory and experiment at an unprecedented level for anyonic quasiparticles. It will constitute an advance towards the generation and manipulation of topologically protected exotic states.