Controlling Quantum Dot Qubits with Modular Instruments

This technical report discusses the efforts of Dr. Takashi Nakajima and his team at RIKEN’s Quantum Functional System Research Group in stabilizing quantum dot qubits for enhanced quantum computing. The document outlines the challenges faced in detecting small charge changes in quantum dots due to noise sensitivity and the need for real-time control. The team employed digital proportional-integral-differential (PID) control synchronized with qubit control signals using Keysight's Arbitrary Waveform Generator (AWG). The report details how the use of Keysight’s PathWave FPGA software facilitated rapid deployment and programming of hardware in the loop (HIL) systems, significantly reducing development time. Future goals include implementing a digital down converter for quantum error correction and scaling up to a larger qubit system. The report emphasizes the importance of tight synchronization and improved error correction as the team progresses towards achieving real-time control in quantum computing applications.