MIT News September 6, 2024
The chiral edge modes lie at the heart of the integer and fractional quantum Hall effects, and their robustness against noise and disorder reflects the quantization of Hall conductivity in these systems. Despite their importance, the controllable injection of edge modes, and direct imaging of their propagation, structure and dynamics, remains challenging. Researchers at MIT demonstrated the distillation of chiral edge modes in a rapidly rotating bosonic superfluid confined by an optical boundary. By tuning the wall sharpness they revealed the smooth crossover between soft wall behaviour in which the propagation speed was proportional to wall steepness and the hard wall regime that exhibited chiral free particles. From the skipping motion of atoms along the boundary they inferred the energy gap between the ground and first excited edge bands, and revealed its evolution from the bulk Landau level splitting for a soft boundary to the hard wall limit. They also demonstrated the robustness of edge propagation against disorder… read more. TECHNICAL ARTICLEÂ
Controllable injection of chiral edge modes. Credit: Nature Physics, 06 September 2024Â