Japan's Fujitsu has developed what it described as the world's first new quantum computer prototype that applies a special diamond to the core of computation. The goal is to boost the stability of quantum states and system scalability by using a "diamond spin" approach that differs from existing superconducting methods.

ITmedia Japan reported on Sept. 9 local time that Fujitsu has developed a new quantum computer prototype that uses spins inside diamond as qubits.

The core of the technology is a diamond with a special structure. The diamond used by Fujitsu has a structure in which some carbon is replaced with tin, with vacancies placed in between. Quantum properties such as the resulting electron spins are used as qubits, the basic unit of information processing.

Fujitsu has studied the technology with Delft University of Technology in the Netherlands since 2020. Unlike typical diamond-based quantum computers that mainly replace some carbon with nitrogen, Fujitsu explained that it applied its own structure using tin.

The company highlights the ability to maintain quantum states relatively stably. Qubits in quantum computers can be easily affected by slight changes in the external environment, which can cause errors. Fujitsu explained that the diamond-spin method is relatively resistant to external noise, making it advantageous for improving computational accuracy.

Another feature is that connections between qubits are easy. In quantum computers, it is important not only to increase the number of qubits but also to stably connect and control each qubit. Fujitsu believes the diamond-spin method could also have advantages in expanding to large-scale systems.

One of the most advanced technologies in quantum computing today is the superconducting method, which operates by cooling circuits to extremely low temperatures. Fujitsu is also developing superconducting quantum computers. The diamond-spin method unveiled this time is drawing attention as another quantum computing platform because it can operate at relatively higher temperatures and has strengths in connecting qubits.

Fujitsu does not plan to use the technology only to improve the performance of a single quantum computer. It envisions developing it into a technology that enables quantum computers made with different methods to be connected so they can compute together.

Shintaro Sato (사토 신타로), a fellow at Fujitsu Laboratories and head of the Quantum Laboratory, said the company will continue development both to pursue large-scale deployment of the diamond-spin method and to enable computation by connecting quantum computers.

This is seen as a strategy that also takes into account "heterogeneous quantum computing" that connects quantum systems using multiple methods, at a time when the quantum computing market has not converged on a single technology. Fujitsu plans to pursue both superconducting and diamond-based approaches to secure computational precision, scalability and connectivity at the same time.

The prototype has not proven performance at a level suitable for commercial use. Key tasks remain, including how stably quantum states can be maintained during expansion to large-scale systems and how far actual computational efficiency and error rates can be improved.

Fujitsu's development shows that competition in quantum computers is expanding beyond increasing the number of qubits to how stable computing environments can be implemented using materials and structures. Attention is focused on whether the diamond-spin method can establish itself as an alternative to existing superconducting methods.