Regensburg 2016 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 11: Focus Session: Single Particle Sources for Electronic Devices I (Joint session of HL and TT, organized by HL)

HL 11.3: Vortrag

Montag, 7. März 2016, 12:15–12:30, H10

Squeezing of shot noise using feedback controlled single-electron tunneling — •Timo Wagner¹, Johannes C. Bayer¹, Eddy P. Rugeramigabo¹, Philipp Strasberg², Tobias Brandes², and Rolf J. Haug¹ — ¹Institut für Festkörperphysik, Leibniz Universität, D-30167 Hannover, Germany — ²Institut für Theoretische Physik, TU Berlin, D-10623 Berlin, Germany

Quantum feedback control has been studied intensively in quantum optics for a variety of different mechanism and systems [1]. Here we demonstrate the squeezing of shot noise in a quantum dot (QD) using an exclusively electronic feedback loop. Therefore the single-electron counting statistics [2, 3] is monitored in real-time with a coupled quantum point contact (QPC) and the deviation from a target rate is fed back periodically to speed up or slow down the process. With increasing feedback response we observe a stronger squeezing and faster freezing of the charge current fluctuations. The measurements confirm previous theoretical predictions [4] and show that the feedback loop is very robust even under stronger experimental restrictions. Our technique is analog to the generation of squeezed light with in-loop photodetection in quantum optics [1, 5].

[1] H. M. Wiseman, Quantum Measurment and Control, Cambridge University Press, Cambridge (2009)

[2] S. Gustavson, et al., Surf. Sci. Rep. 64, 191 (2009)

[3] N. Ubbelohde, et al., Nature. Com. 3, 612 (2012)

[4] T. Brandes, Phys. Rev. Lett. 105, 06060 (2010)

[5] S. Machida, Y. Yamamoto, Opt. Commun. 57, 290 (1986)