The R&D Item is responsible for overseeing the entire project and organising the quantum computer as a system and is working on three specific R&D tasks (#1, #2 and #3) in the diagram below.
The first is research on the development of a two-dimensional qubit array of qubits, which is a milestone in the process of scaling up silicon quantum computers. The second is the development of qubit high-precision control and high-sensitivity readout circuits, which are necessary to control this qubit array with high precision and read out quantum information with high sensitivity. The third is to develop the system architecture for operating the entire system as a computer. Through these efforts, we aim to realise a large-scale integrated silicon quantum computing system that utilises the features of silicon semiconductor technology.

In our research on high-precision qubit control and high-sensitivity readout circuits, we proceeded with system evaluation using the QBG chip—developed by fiscal year 2024—which supplies control signals for qubit manipulation, and successfully demonstrated charge shuttling operations. Regarding high-sensitivity readout circuits, we implemented a reflected readout method in the system and performed spin measurements using the Elzerman readout. In our research on system architecture, we constructed an automated qubit manipulation system designed for large-scale operations. By integrating experimental and measurement modules with an automatic calibration library, we automated qubit operations and completed the implementation of a data management system (database, management interface, and results UI), thereby verifying traceability and automatic calibration functions. Using this system, we accumulated daily experimental and calibration data over the long term. We confirmed automatic calibration that adapts to temperature fluctuations, as well as automatic calibration in response to variations in device characteristics (Figure 3).