研究目的
To improve the sensitivity and speed of gate-based readout of silicon quantum dots using Josephson parametric amplification for quantum computing applications.
研究成果
The study demonstrates that the SNR of rf gate-based readout of quantum dot devices can be significantly improved using a JPA, enabling faster and more sensitive readout suitable for quantum computing applications. The JPA allows operation at lower rf power while maintaining identical SNR, and further improvements in JPA gain and circuit design could enhance performance.
研究不足
The measurement speed is limited by the bandwidth of the high-Q readout resonator. The dynamic range of the JPA is limited, making it unsuitable for higher signal powers commonly used in reflectometry measurements.
1：Experimental Design and Method Selection:
The study combines radio-frequency gate-based sensing with a Josephson parametric amplifier (JPA) to enhance the readout of silicon double quantum dots. The JPA operates in the 500–800 MHz band, and the setup includes a cryogenic rf delivery and amplification chain, a lumped-element LC resonator, and the silicon quantum dot device.
2：Sample Selection and Data Sources:
The experiment uses silicon multidot devices with large gate coupling, fabricated following CMOS processes, to benchmark the sensitivity of the method.
3：List of Experimental Equipment and Materials:
The setup includes a JPA, a lumped-element LC resonator with a NbN spiral inductor, and a silicon quantum dot device. The JPA is a low quality factor superconducting resonator consisting of a SQUID loop array with tunable inductance shunted by a fixed capacitance.
4：Experimental Procedures and Operational Workflow:
The LC resonator is probed using an rf tone, and parametric changes in device capacitance due to single-electron tunneling produce changes in the reflection coefficient. The JPA is used to amplify the signal, improving the signal-to-noise ratio (SNR).
5：Data Analysis Methods:
The SNR is calculated from the amplitude of the signal and the rms amplitude of the noise. The performance is benchmarked using electronic transitions in the silicon devices.
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