Strong suppression of shot noise in a feedback-controlled single-electron transistor.
Feedback control of quantum mechanical systems is rapidly attracting attention not only due to fundamental questions about quantum measurements, but also because of its novel applications in many fields in physics. Quantum control has been studied intensively in quantum optics but progress has recently been made in the control of solid-state qubits as well. In quantum transport only a few active and passive feedback experiments have been realized on the level of single electrons, although theoretical proposals exist. Here we demonstrate the suppression of shot noise in a single-electron transistor using an exclusively electronic closed-loop feedback to monitor and adjust the counting statistics. With increasing feedback response we observe a stronger suppression and faster freezing of charge current fluctuations. Our technique is analogous to the generation of squeezed light with in-loop photodetection as used in quantum optics. Sub-Poisson single-electron sources will pave the way for high-precision measurements in quantum transport similar to optical or optomechanical equivalents.
Institut für Festkörperphysik, Leibniz Universität Hannover, D-30167 Hannover, Germany.
Timo
T
Wagner
Institut für Theoretische Physik, Hardenbergstr. 36, TU Berlin, D-10623 Berlin, Germany.
Philipp
P
Strasberg
Institut für Festkörperphysik, Leibniz Universität Hannover, D-30167 Hannover, Germany.
Johannes C
JC
Bayer
Institut für Festkörperphysik, Leibniz Universität Hannover, D-30167 Hannover, Germany.
Eddy P
0000-0002-3532-2902
EP
Rugeramigabo
Institut für Theoretische Physik, Hardenbergstr. 36, TU Berlin, D-10623 Berlin, Germany.
Tobias
T
Brandes
Institut für Festkörperphysik, Leibniz Universität Hannover, D-30167 Hannover, Germany.
Rolf J
RJ
Haug