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

• URL: http://arxiv.org/abs/2103.15258v1
• Date: Mon, 29 Mar 2021 01:03:41 GMT
• Title: Real-Time Feedback Control of Charge Sensing for Quantum Dot Qubits
• Authors: Takashi Nakajima, Yohei Kojima, Yoshihiro Uehara, Akito Noiri, Kenta Takeda, Takashi Kobayashi, Seigo Tarucha
• Abstract summary: We demonstrate realtime operation of a charge sensor in a feedback loop to maintain its sensitivity for fast charge sensing in a Si/SiGe double quantum dot. The rapid automated tuning of a charge sensor enables unobstructed charge stability diagram measurement realtime quantum dot tuning and submicrosecond single-shot spin readout.
• Score: 0.0
• License: http://arxiv.org/licenses/nonexclusive-distrib/1.0/
• 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 $\approx 100\,{\rm kHz}$. 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.

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