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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 measurements1, but also because of its novel applications in many fields in physics. Quantum control has been studied intensively in quantum optics1,2 but progress has recently been made in the control of solid-state qubits3,4,5 as well. In quantum transport only a few active6,7,8 and passive9,10,11 feedback experiments have been realized on the level of single electrons, although theoretical proposals12,13,14 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 statistics6,15,16,17,18,19,20. 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 photodetection1,21,22 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 optomechanical23 equivalents.

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Figure 1: Feedback set-up.
Figure 2: Detailed feedback processing.
Figure 3: Stationary and feedback distributions.
Figure 4: Feedback-dependent cumulants of the charge fluctuations.


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We thank G. Haack for the valuable discussions. This work was financially supported by the DFG GRK 1991, QUEST (T.W, J.C.B., E.P.R. and R.J.H.) and DFG SFB 910, GRK 1558 (P.S. and T.B.).

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T.W. carried out the experiments, analysed the data and wrote the manuscript. J.C.B. and T.W. fabricated the device. E.P.R. provided the wafer material. P.S and T.B. provided theory support and supplied Supplementary Material. R.J.H. supervised the research. All authors discussed the results and contributed to editing the manuscript.

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Correspondence to Timo Wagner.

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The authors declare no competing financial interests.

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Wagner, T., Strasberg, P., Bayer, J. et al. Strong suppression of shot noise in a feedback-controlled single-electron transistor. Nature Nanotech 12, 218–222 (2017).

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