Spatially-resolved analysis of edge-channel equilibration in quantum   Hall circuits
  We demonstrate an innovative quantum Hall circuit with variable geometry employing the moveable electrostatic potential induced by a biased atomic force microscope tip. We exploit this additional degree of freedom to identify the microscopic mechanisms that allow two co-propagating edge channels to equilibrate their charge imbalance. Experimental results are compared with tight-binding simulations based on a realistic model for the disorder potential. This work provides also an experimental realization of a beam mixer between co-propagating edge channels, a still elusive building block of a recently proposed new class of quantum interferometers. 
Nicola Paradiso, Stefan Heun, Stefano Roddaro, Davide Venturelli,   Fabio Taddei, Vittorio Giovannetti, Rosario Fazio, Giorg...
cond-mat.mes-hall quant-ph