Diamond-spin quantum computer prototype

Raveh Neeman

doi:10.5281/zenodo.22674814

Fujitsu (with TU Delft and QuTech) · defect spins · DEMONSTRATED (working prototype; test environment) (Sep 2026) · qubits not published · access: test environment via the Fujitsu Hybrid Quantum Computing Platform

architecture: Colour-centre spins — network nodes (NV/SiV/T) · Open on the map

Register profile — the machine's variant of its architecture

qubit type: tin-vacancy (SnV) centre spin in diamond

gate mechanism: combined light, microwave and radio-frequency control; gate-level circuits converted into control sequences

control: optical, microwave and RF drive; Fujitsu circuit-to-control-sequence conversion

control placement: module at 1.55 K (-271.6 °C); electronics placement not published

readout: single photons emitted by the SnV centre guided by an alumina waveguide on a photonic integrated circuit

flags: no published error rates

Technologies by layer — the machine's cell per layer

1 Qubit carrier	Colour-centre / defect spin (NV, SiV, SnV, T centre) · primary ▨ opening paragraph (SnV centers in photonic integrated circuits) ✅ SnV centres in nanoscale diamond integrated into photonic integrated circuits
2 Encoding	Single-spin (Loss–DiVincenzo) / nuclear-spin encoding · primary ◌ 🔎 single-spin encoding (family-determined); electron or nuclear spin qubits not stated
3 Gate mechanism	Microwave / optical spin gates (defect centres, 1Q spins) · primary ▨ Overview of developed technologies: quantum circuit conversion for the diamond spin approach ✅ qubit control by combined light, microwaves and RF waves; gate-level circuits converted into these control sequences
4 Connectivity / transport	— undisclosed — exists, nothing published ▨ 🔎 on-module connectivity not published
5 Control	— (Atlas gap: ∅G-nvroom) · primary ▨ Overview of developed technologies (control combining light, microwaves and RF) ✅ light, microwave and RF control of SnV spins; module operated at -271.6 °C (1.55 K)
6 Readout	Fluorescence state detection (ions, defects) · primary ▨ Overview of developed technologies: PIC fabrication for SnV centres (single photons extracted during readout) ✅ single photons emitted by the SnV centre extracted through the alumina waveguide for qubit readout
7 Code	— none — nothing in this layer ◌ 🔎 no QEC reported; prototype without published figures
8 Decoder	— none — nothing in this layer ◌ 🔎 no decoder; no QEC
9 Interconnect	— none — nothing in this layer ▨ prototype paragraph (single diamond-based quantum module) ✅ current prototype is a single diamond-based quantum module; multi-module system with optical connectivity planned for 2027
10 Manufacturing	Diamond growth / implantation (NV, SiV, SnV) · primary ▨ Overview of developed technologies: heterogeneous material bonding and thinning; PIC fabrication for SnV centres ✅ nanometre-sized diamond crystals containing SnV centres, heterogeneous bonding and thinning onto the chip Photonic IC foundry (SiN, BTO, TFLN, SNSPD on 300 mm) · alternate ▨ Overview of developed technologies: PIC fabrication for SnV centres (alumina optical waveguides) ✅ photonic integrated circuit with alumina optical waveguides, transparent in the visible, carrying the SnV diamond

evidence: ✅ 7 / 11