# Fast Charge Sensing of a Cavity-Coupled Double Quantum Dot Using a Josephson Parametric Amplifier

## Author(s): Stehlik, J; Liu, Y-Y; Quintana, CM; Eichler, C; Hartke, TR; et al

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 Abstract: We demonstrate fast readout of a double quantum dot (DQD) that is coupled to a superconducting resonator. Utilizing a parametric amplifier beyond its range of linear amplification, we improve the signal-to-noise ratio (SNR) by a factor of 2000 compared to the situation with the parametric amplifier turned off. With an integration time of 400 ns comparable to the inverse effective bandwidth, we achieve a SNR of 76. By measuring the SNR as a function of the integration time, we extract an equivalent charge sensitivity of 8 x 10(-5) e/root Hz. The high SNR allows us to acquire a DQD charge-stability diagram in just 20 ms. At such a high data rate, it is possible to acquire charge-stability diagrams in a live “video mode,” enabling real-time tuning of the DQD confinement potential. Publication Date: Jul-2015 Electronic Publication Date: 27-Jul-2015 Citation: Stehlik, J, Liu, Y-Y, Quintana, CM, Eichler, C, Hartke, TR, Petta, JR. (2015). Fast Charge Sensing of a Cavity-Coupled Double Quantum Dot Using a Josephson Parametric Amplifier. PHYSICAL REVIEW APPLIED, 4 (10.1103/PhysRevApplied.4.014018 DOI: doi:10.1103/PhysRevApplied.4.014018 ISSN: 2331-7019 Type of Material: Journal Article Journal/Proceeding Title: PHYSICAL REVIEW APPLIED Version: Final published version. Article is made available in OAR by the publisher's permission or policy.