The project uses diamond-based qubits and operates at temperatures slightly warmer than conventional superconducting systems, featuring three core innovations

The 8 September 2026 launch of the world’s first working prototype of a ‘diamond-spin’ quantum computer has marked a significant departure from the superconducting qubit architectures dominant in the industry.

The system leverages ‘tin-vacancy centers’ — engineered defects in diamond crystals where a tin atom sits between two adjacent vacancies — as qubits. These color centers are embedded within photonic integrated circuits, exploiting the inherent stability of quantum states in diamond to achieve high operational fidelity with potentially fewer physical qubits required per logical qubit than competing approaches.

The prototype operates at minus 271.6 degrees Celsius, a temperature slightly warmer than the roughly minus 273.13 degrees demanded by superconducting quantum systems. In a controlled test environment, the hardware can be accessed without requiring specialist quantum knowledge from users. Three core technological innovations enable the system:

  1. a ‘quantum circuit conversion’ mechanism that translates standard quantum gate instructions into the light, microwave, and radio frequency signals needed to control diamond-spin qubits
  2. a heterogeneous material bonding process that attaches high-quality diamond substrates to alumina and silicon dioxide substrates while thinning the diamond from hundreds of micrometers down to hundreds of nanometers
  3. a photonics-integrated circuit fabrication method that pairs nanometer-sized diamond crystals with alumina optical waveguides

This achievement rests on a collaborative foundation established in 2020 between Fujitsu, Delft University of Technology, and QuTech quantum research institute. In March 2025, the group had demonstrated a complete universal quantum gate set for diamond spin qubits with an error probability below 0.1%, among the highest fidelities reported across all quantum hardware platforms to date.

Earlier this year, the group had also successfully demonstrated entanglement and quantum gate operations between remote nitrogen-vacancy centers housed in separate cryostats, advancing the feasibility of distributeAd quantum computing architectures. Looking ahead, they plan to develop a multi-