On Noise-Sensitive Automatic Tuning of Gate-Defined Sensor Dots

IEEE Transactions on Quantum Engineering, vol. 4, pp. 1–18

Abstract

In gate-defined quantum dot systems, the conductance change of electrostatically coupled sensor dots allows the observation of the quantum dots' charge and spin states. Therefore, the sensor dot must be optimally sensitive to changes in its electrostatic environment. A series of conductance measurements varying the two sensor-dot-forming barrier gate voltages serve to tune the dot into a corresponding operating regime. In this article, we analyze the noise characteristics of the measured data and define a criterion to identify continuous regions with a sufficient signal-gradient-to-noise ratio. Hence, accurate noise estimation is required when identifying the optimal operating regime. Therefore, we evaluate several existing noise estimators, modify them for 1-D data, optimize their parameters, and analyze their quality based on simulated data. The estimator of Chen et al. turns out to be best suited for our application concerning minimally scattering results. Furthermore, using this estimator in an algorithm for flank-of-interest classification in measured data shows the relevance and applicability of our approach.

Authors 7

1. Fabian Hader

   Forschungszentrum Jülich

   Affiliation as printed

   Central Institute of Engineering, Electronics and Analytics ZEA-2 – Electronic Systems, Forschungszentrum Jülich GmbH, Jülich, Germany

2. Jan Vogelbruch

   Forschungszentrum Jülich

   Affiliation as printed

   Central Institute of Engineering, Electronics and Analytics ZEA-2 – Electronic Systems, Forschungszentrum Jülich GmbH, Jülich, Germany

3. Simon Humpohl Aachen JARA-FIT Institute for Quantum Information

   Jülich Aachen Research Alliance · RWTH Aachen University

   Affiliation as printed

   JARA-FIT Institute for Quantum Information, Forschungszentrum Jülich GmbH and RWTH Aachen University, Aachen, Germany

4. Tobias Hangleiter Aachen JARA-FIT Institute for Quantum Information

   Jülich Aachen Research Alliance · RWTH Aachen University

   Affiliation as printed

   JARA-FIT Institute for Quantum Information, Forschungszentrum Jülich GmbH and RWTH Aachen University, Aachen, Germany

5. Chimezie Eguzo

   Forschungszentrum Jülich

   Affiliation as printed

   Central Institute of Engineering, Electronics and Analytics ZEA-2 – Electronic Systems, Forschungszentrum Jülich GmbH, Jülich, Germany

6. Stefan J. Heinen

   Forschungszentrum Jülich

   Affiliation as printed

   Central Institute of Engineering, Electronics and Analytics ZEA-2 – Electronic Systems, Forschungszentrum Jülich GmbH, Jülich, Germany

7. Stefan van Waasen

   Forschungszentrum Jülich · University of Duisburg-Essen

   Affiliation as printed

   Central Institute of Engineering, Electronics and Analytics ZEA-2 – Electronic Systems, Forschungszentrum Jülich GmbH, Jülich, Germany

   Faculty of Engineering -Communication Systems, University of Duisburg-Essen, 47057 Duisburg, Germany