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Measurement Back-Action in Quantum Point-Contact Charge Sensing
Solid State Physics Laboratory, ETH Zurich, Schafmattstr. 16, 8093 Zurich, Switzerland
Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
EMPA, 8600 Dübendorf, Switzerland
Theoretische Physik, ETH Zurich, Wolfgang-Pauli-Str. 27, 8093 Zurich, Switzerland
Instituut-Lorentz, Universiteit Leiden, P.O. Box 9506, 2300 RA Leiden, The Netherlands
Institut für Experimentelle und Angewandte Physik, Universität Regensburg, 93040 Regensburg, Germany
FIRST Laboratory, ETH Zurich, Wolfgang-Pauli-Str. 10, 8093 Zurich, Switzerland
* Author to whom correspondence should be addressed.
Received: 10 May 2010; in revised form: 21 June 2010 / Accepted: 25 June 2010 / Published: 29 June 2010
Abstract: Charge sensing with quantum point-contacts (QPCs) is a technique widely used in semiconductor quantum-dot research. Understanding the physics of this measurement process, as well as finding ways of suppressing unwanted measurement back-action, are therefore both desirable. In this article, we present experimental studies targeting these two goals. Firstly, we measure the effect of a QPC on electron tunneling between two InAs quantum dots, and show that a model based on the QPC’s shot-noise can account for it. Secondly, we discuss the possibility of lowering the measurement current (and thus the back-action) used for charge sensing by correlating the signals of two independent measurement channels. The performance of this method is tested in a typical experimental setup.
Keywords: quantum dots; quantum wires; noise; single-electron tunneling
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Küng, B.; Gustavsson, S.; Choi, T.; Shorubalko, I.; Pfäffli, O.; Hassler, F.; Blatter, G.; Reinwald, M.; Wegscheider, W.; Schön, S.; Ihn, T.; Ensslin, K. Measurement Back-Action in Quantum Point-Contact Charge Sensing. Entropy 2010, 12, 1721-1732.
Küng B, Gustavsson S, Choi T, Shorubalko I, Pfäffli O, Hassler F, Blatter G, Reinwald M, Wegscheider W, Schön S, Ihn T, Ensslin K. Measurement Back-Action in Quantum Point-Contact Charge Sensing. Entropy. 2010; 12(7):1721-1732.
Küng, Bruno; Gustavsson, Simon; Choi, Theodore; Shorubalko, Ivan; Pfäffli, Oliver; Hassler, Fabian; Blatter, Gianni; Reinwald, Matthias; Wegscheider, Werner; Schön, Silke; Ihn, Thomas; Ensslin, Klaus. 2010. "Measurement Back-Action in Quantum Point-Contact Charge Sensing." Entropy 12, no. 7: 1721-1732.