Sensitive radiofrequency readout of quantum dots using an ultra-low-noise SQUID amplifier

Schupp, F. J. and Vigneau, F. and Wen, Y. and Mavalankar, A. and Griffiths, J. and Jones, G. A. C. and Farrer, I. and Ritchie, D. A. and Smith, C. G. and Camenzind, L. C. and Yu, L. and Zumbühl, D. M. and Briggs, G. A. D. and Ares, N. and Laird, E. A.. (2020) Sensitive radiofrequency readout of quantum dots using an ultra-low-noise SQUID amplifier. Journal of Applied Physics, 127 (24). p. 244503.

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Fault-tolerant spin-based quantum computers will require fast and accurate qubit read out. This can be achieved using radiofrequency reflectometry given sufficient sensitivity to the change in quantum capacitance associated with the qubit states. Here, we demonstrate a 23-fold improvement in capacitance sensitivity by supplementing a cryogenic semiconductor amplifier with a SQUID preamplifier. The SQUID amplifier operates at a frequency near 200 MHz and achieves a noise temperature below 600 mK when integrated into a reflectometry circuit, which is within a factor 120 of the quantum limit. It enables a record sensitivity to capacitance of 0.07aF/Hz‾‾‾√. The setup is used to acquire charge stability diagrams of a gate-defined double quantum dot in a short time with a signal-to-noise ration of about 38 in 1μs of integration time.
Faculties and Departments:05 Faculty of Science > Departement Physik > Physik > Experimentalphysik Quantenphysik (Zumbühl)
UniBasel Contributors:Zumbühl, Dominik M
Item Type:Article, refereed
Article Subtype:Research Article
Publisher:AIP Publishing
Note:Publication type according to Uni Basel Research Database: Journal article
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Last Modified:12 Apr 2021 11:58
Deposited On:12 Apr 2021 11:58

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