Fujitsu Unveils Prototype Quantum Computer Using Diamond Qubits

Fujitsu has developed a functioning prototype of a quantum computer utilizing diamond spin qubits. The company aims to leverage photonic connections to scale the system and plans to create a multi-module version by 2027.

Diamond-Based Quantum Computer

The Fujitsu prototype is based on tin-vacancy (SnV) centers within diamond, which serve as qubits. These are integrated with photonic integrated circuits to read quantum states using light.

According to the company, the prototype operates at approximately −271.6 °C, slightly above the typical operating environment for superconducting quantum computers (around −273.13 °C). Fujitsu also showcased the ability to manage the system via its proprietary Hybrid Quantum Computing Platform, eliminating the need for users to understand the underlying hardware architecture separately.

Source: Fujitsu.

The company claims this is the first working prototype of a quantum computer of its kind with integrated SnV centers and photonic circuits.

Key Feature: Scalability

A significant aspect of this architecture is that individual quantum modules can be connected using light. This potentially allows for the construction of larger systems composed of several relatively small blocks, rather than attempting to fit all qubits into a single device.

The diamond platform uses defects in the crystal lattice as qubits. Fujitsu opted for SnV centers over the more commonly used NV centers, stating that SnV centers offer structural symmetry and are less susceptible to external noise.

Source: Fujitsu.

For the prototype, the company also developed technologies to bond diamond with other materials and reduce the thickness of the diamond layer from hundreds of micrometers to hundreds of nanometers. This is essential for integrating diamond structures with photonic circuits.

Next Steps: Multiple Modules

By 2027, Fujitsu plans to produce a prototype quantum computer consisting of multiple diamond modules. Concurrently, the company will begin developing technology to combine diamond and superconducting architectures.

The prototype's creation stems from collaborative research between Fujitsu, Delft University of Technology, and the QuTech research center, which began in 2020. The project has also received support from the Dutch program Holland High Tech.

In the long term, Fujitsu aims to develop a system with 250 logical qubits by 2030 and 1000 logical qubits by 2035. These targets are part of the technology roadmap and not yet achieved milestones.

Additionally, ForkLog recently examined in its Quantum & After episode who finances the quantum race, the costs involved, and how to distinguish real progress from marketing hype.