Summary of the project

Quantum computers will revolutionize solutions to societal challenges such as drug discovery, artificial photosynthesis, and room-temperature superconductivity, while enabling fully secure communication.
This project develops a scalable ion trap device by connecting multiple small ion traps using light—a novel approach that allows flexible expansion of qubit numbers. Our goal is to realize a large-scale, fault-tolerant universal quantum computer by 2050.

Milestone by year 2030

We aim to realize a logical qubit on a quantum network composed of optically connected ion trap modules (Fig. 1).

The main objective is to demonstrate the scalability of ion trap quantum computers via optical interconnects. To achieve this, we will develop modules integrating optical cavities and quantum charge-coupled devices (quantum CCDs), and establish quantum optical links. In parallel, we will explore advanced technologies such as cryogenic environments, microwave control, bosonic codes, and ion–atom interfaces. These efforts will lay the foundation for future large-scale, universal quantum computers.

Milestone by year 2025

We are developing ion trap modules capable of scalable qubit expansion (as shown in Figure 1: Ion Trap Module), and aim to demonstrate their ability to reach the scale required for quantum error correction. To achieve this, we are advancing technologies such as high-fidelity spin control, phonon-based encoding, optical coupling, and laser delivery via integrated photonic circuits. We are also establishing ion transport and arrangement using junction structures, and building a compact quantum computing platform for cloud deployment. These efforts contribute to a robust foundation for distributed quantum computing.
Our research and development efforts are guided by the following three-layered technology strategy:

Core technologies:

Quantum optical interconnects between remote ions,
microwave gates, integrated photonic circuits, and ion transport and arrangement.

Innovative technologies:

Exploration of new quantum functionalities using vibrational quanta and Rydberg ions.

Foundational technologies:

Precision microfabrication of ion traps and cloud-ready hardware platforms to enhance modularity and practical deployment.

R&D theme progress reports

• [1] Research and development for photonic interconnects of ion traps
• [2] Superconducting circuit ion traps with low-vibrational cryostat
• [3] Quantum Error Correction Using the Phononic DoF
• [4-1] Fabrication and evaluation techniques of high-performance ion traps
• [4-2] R&D for Cloud Quantum Computing
• [5] Research and development on integrated optical circuits for ion trapping
• [6] Arranging individual trapped ions with junction traps
• [7] Development of quantum interfaces between ions and atoms
• Progress Report (1.52MB)

Performers

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• Summary of the project (170KB)