“German startup Saxon Q just built the first diamond based quantum system with more than 10 cubits [qubits]." (video transcript) / "German startup Saxon Q says it's built the first diamond-based quantum computer with more than ten qubits... They claim 99.98 percent single-qubit fidelity, though there's no peer-reviewed paper yet."…”

The announcement is real and appears on the company's own channel. SAXON Q announced the commercial availability of the 128-qubit SXQ128 and 512-qubit SXQ512, described as the first diamond-based NV-center quantum computers to ever exceed 10 qubits, with both systems operating at room temperature with no cryogenic cooling, vacuum equipment or specialized facilities required. The decisive omitted detail is how the qubit count is constructed. Through its proprietary multi-core quantum operating system, the SXQ128 offers eight fully entangled qubits per core, while the SXQ512 features 16 per core. An independent technical analysis makes the consequence explicit: the SXQ128 distributes its 128 physical qubits across 16 processing cores, with SAXON Q describing eight "fully entangled" qubits per core, and comparing 128 aggregate qubits across sixteen classically coordinated 8-qubit cores to 105 qubits in a single connected register is a category error, because the two numbers measure different things: Willow's 105 describes the width of a coherent processor, while SXQ128's 128 describes total capacity across independent cores. That matters against the prior art. In 2019 a Delft team realized a ten-qubit quantum register consisting of the electron spin of a nitrogen-vacancy center and nine nuclear spins in diamond, and showed the register was fully connected by generating entanglement between all 45 possible qubit pairs. SAXON Q's disclosed coherent register width, eight qubits per core, is smaller than that seven-year-old laboratory result. On the fidelity number: every source, including the vendor's own release, reports 99.92 percent, not 99.98. The resulting qubits achieve up to 99.92% fidelity, fewer than one error per 1,000 operations. The more load-bearing metric is absent from the release: the whitepaper contains a specification table that the press release omitted, listing for the Gen3 QC2026 Dual Core single-qubit gate fidelity "up to 0.9992" and two-qubit gate fidelity of 0.97, and that two-qubit number is the figure that matters for circuit depth and is absent from every press release and news article about the SXQ128. The caption's assertion that there is "no peer-reviewed paper yet" is wrong about the fabrication technique the video spends most of its time explaining. In 2019, Meijer and colleagues published a 75.3% NV-centre creation yield using sulfur-assisted charge engineering in Nature Communications, roughly a tenfold improvement, and the paper itself states a high creation yield of NV centres of 75% (a tenfold enhancement) by charge-assisted defect engineering, together with an improvement of their spin coherence. SAXON Q now says its proprietary production process exceeds 85%, but that higher number remains company-reported; the peer-reviewed result is 75.3%. The deployment track record is real but at a much smaller scale than the headline. SAXON Q delivered a 4-qubit system to DLR's Innovation Center in 2023; after testing against thresholds of >95% single-qubit and >90% two-qubit gate fidelity, DLR accepted the system in July 2024, and it has been available via QCI Connect since August 2025. A second 4-qubit system was deployed at Fraunhofer IWU in Dresden in June 2025. The 99.92 percent figure is not from a delivered 128-qubit machine: the 99.92% fidelity in the announcement appears to be the same single-qubit randomized-benchmarking result for one nuclear-spin qubit from the Gen3 system. Lifecycle: the SXQ128 is available to order now, with delivery within three months of order placement, and the SXQ512 is available to order with deliveries beginning Q2 2027. Independent scrutiny remains absent: the 99.92% single-gate fidelity and >85% yield figures come from SAXON Q's own press materials and website, not from peer-reviewed third-party benchmarking; independent benchmarks for the 512-qubit system are absent; and the company has not published coherence times or two-qubit gate fidelities.