Fujitsu Presents a Revolutionary Diamond-Based Quantum Computer

Japanese technology giant Fujitsu has taken a significant step forward in the field of quantum computing by unveiling the world’s first prototype of a functioning quantum computer built on diamond spins. This innovative development uses the unique properties of tin-vacancy (SnV) centers integrated into photonic integrated circuits, opening new horizons for creating more powerful and efficient quantum systems.

Unlike traditional superconducting quantum computers that require extremely low temperatures close to absolute zero, Fujitsu’s new development demonstrates functionality at a significantly higher temperature — -271.6 degrees Celsius. This greatly simplifies operation and reduces energy costs, bringing quantum computing closer to practical use. Fujitsu’s research team says that using light to connect individual computing modules is a key factor that could lead to computers that far surpass current capabilities.

From Atomic Defects to Powerful Computing

At the heart of the new technology are special defects in the diamond crystal lattice known as color centers. Traditionally, nitrogen-vacancy (NV) centers have been used in diamond spin systems, where a nitrogen atom occupies a carbon site next to a vacancy. However, Fujitsu focused on tin-vacancy (SnV) centers. These defects are characterized by a tin atom positioned between two vacancies in the diamond structure.

“The symmetric structure makes SnV centers less sensitive to external noise than traditional NV centers. In addition, SnV centers emit light about 10 times brighter than NV centers. This could potentially improve optical connections between quantum modules,” explained Fujitsu representatives.

This feature gives SnV centers significant advantages. Their resistance to external influences means a lower likelihood of losing quantum states, which is critically important for stable qubit operation. Brighter light emission makes optical coupling between individual quantum modules easier, which is key to scaling the system. In addition, this approach promises more efficient error correction. The specific properties of SnV centers make it possible to form logical qubits — the foundation of quantum computing — using fewer physical qubits compared with competing technologies. This means fewer resources will be needed to run complex quantum algorithms, accelerating progress toward practical quantum applications.

The company has already outlined ambitious development plans. By 2027, Fujitsu plans to present a multi-module prototype of a diamond spin computer, and by 2030 — make quantum computing commercially available. According to its roadmap, a 250-logical-qubit system will be developed by fiscal 2030, and a system with 1,000 logical qubits by fiscal 2035.

Integrating Diamond into a Quantum Chip: An Engineering Masterpiece

Creating such a complex device required advanced engineering solutions. Fujitsu developed a special process that allows high-quality diamond substrates with implanted tin to be integrated into aluminum oxide and silicon dioxide substrates. The diamond, originally several hundred micrometers thick, was finely processed down to several hundred nanometers to become part of the quantum chips.

“The diamond-spin approach we used in this prototype not only offers exceptional scalability on its own, but also has the potential to integrate with superconducting quantum computers in order to further expand their capabilities and perform more complex and larger-scale computations,” said Fujitsu CTO Vivek Mahajan.

At the same time, the company developed photonic integrated circuits that efficiently combine nanoscale diamond crystals with SnV centers and aluminum oxide optical waveguides. An important element of the system is the developed mechanism for controlling diamond spin qubits using light, microwaves, and radio-frequency waves. This allows precise qubit state control, which is necessary for executing complex quantum algorithms.

This achievement is the result of a long-term collaboration between Fujitsu, Delft University of Technology, and QuTech, which began in 2020. Koen Eikelenboom, CEO of QuTech, highlighted the significance of this prototype as the result of joint research.

The new technology could be used to solve problems beyond the reach of modern supercomputers, including drug discovery, materials science, optimization of complex logistics chains, and cryptography. Fujitsu also aims to make quantum computing accessible to a wider range of users by integrating the development into a hybrid quantum computing platform that does not require deep specialized knowledge to work with the hardware. This move shows the company’s commitment to making quantum technologies more practical and accessible.