Japan switches on a neutral-atom quantum computer with about 50 qubits

On August 24, a new machine began running at Japan’s Institute for Molecular Science. Called Shunkai, it is the country’s first operational full-stack neutral-atom quantum computer, starting with approximately 50 qubits and a path toward around 500. The research team is led by Kenji Ohmori, a chemist and professor at IMS.

The machine’s quantum processing unit, or QPU, was supplied by Colorado-based quantum technology company Infleqtion. Its approach uses individual atoms as qubits, trapping and manipulating them with precisely controlled laser light. The atoms can be arranged in arrays, while their connections and layout can be adjusted for different algorithms. Unlike some quantum systems, neutral-atom computers can operate at room temperature without large refrigeration systems.

That architecture is promising because it may let engineers build larger arrays while retaining precise control of the atoms’ quantum states. But size is only part of the problem. Quantum systems are sensitive to their environments, so errors can accumulate during calculations. The researchers still need to develop error-detection and correction methods before Shunkai can become fault-tolerant.

The next phase of the Ohmori Moonshot project began in April 2026 and targets better integration, stability and scalability, ultimately including as many as 10,000 physical qubits. The Japan Science and Technology Agency selected Infleqtion as the Quantum Moonshot program’s only foreign quantum partner. The program is pursuing fault-tolerant universal quantum computers by 2050.

And so, concretely? Shunkai gives researchers an operating platform rather than a laboratory component alone. The team expects eventually to open it to outside universities and companies, allowing them to work on quantum error correction and applications, while a planned connection to IMS’s shared supercomputer facility would create a hybrid quantum–graphics processing unit (GPU) computing center. The system is running now; broader access and fault tolerance remain planned steps.