Real-Time Feedback Control of Charge Sensing for Quantum Dot Qubits

Abstract

Measurement of charge configurations in few-electron quantum dots is a vital technique for spin-based quantum information processing. While fast and high-fidelity measurement is possible by using proximal quantum dot charge sensors, their operating range is limited and prone to electrical disturbances. Here we demonstrate realtime operation of a charge sensor in a feedback loop to maintain its sensitivity suitable for fast charge sensing in a Si/SiGe double quantum dot. Disturbances to the charge sensitivity, due to variation of gate voltages for operating the quantum dot and $1/f$ charge fluctuation, are compensated by a digital PID controller with the bandwidth of $\approx 100\mathrm{kHz}$. The rapid automated tuning of a charge sensor enables unobstructed charge stability diagram measurement facilitating realtime quantum dot tuning and submicrosecond single-shot spin readout without compromising the performance of a charge sensor in time-consuming experiments for quantum information processing.

arXiv comment6 pages, 4 figures

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Cited by in corpus (10)

• Probing quantum devices with radio-frequency reflectometry
• Real-time two-axis control of a spin qubit
• Measurement of tunnel coupling in a Si double quantum dot based on charge sensing
• Wide dynamic range charge sensor operation by high-speed feedback control of radio-frequency reflectometry
• Stabilizing an individual charge fluctuator in a Si/SiGe quantum dot
• Efficient adaptive Bayesian estimation of a slowly fluctuating Overhauser field gradient
• RFSoC-based radio-frequency reflectometry in gate-defined bilayer graphene quantum devices
• Charge state estimation in quantum dots using a Bayesian approach
• Rapid Autotuning of a SiGe Quantum Dot into the Single-Electron Regime with Machine Learning and RF-Reflectometry FPGA-Based Measurements
• Entropic costs of extracting classical ticks from a quantum clock