A quantized current source with mesoscopic feedback
  We study a mesoscopic circuit of two quantized current sources, realized by non-adiabatic single- electron pumps connected in series with a small micron-sized island in between. We find that quantum transport through the second pump can be locked onto the quantized current of the first one by a feedback due to charging of the mesoscopic island. This is confirmed by a measurement of the charge variation on the island using a nearby charge detector. Finally, the charge feedback signal clearly evidences loading into excited states of the dynamic quantum dot during single-electron pump operation. 
Lukas Fricke, Frank Hohls, Niels Ubbelohde, Bernd Kaestner,   Vyacheslavs Kashcheyevs, Christoph Leicht, Philipp Mirovsky, K...
cond-mat.mes-hall