§ Claim under review · Release
"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." (caption)
Verdict
Partially accurate but misleading
Confidence
MediumSummary
SAXON Q, a Leipzig spin-out, really did announce on 21 July 2026 that it is selling diamond-based quantum computers that run at room temperature in a standard server rack, and it really does describe them as the first NV-diamond systems to exceed ten qubits. The catch is in how the qubits are counted. The 128-qubit model is sixteen separate 8-qubit cores linked by ordinary classical coordination, so the largest group of qubits that can actually work together is eight, which is fewer than the ten-qubit diamond register a Dutch university team published back in 2019. The video also states 99.98 percent accuracy, but the company's own figure is 99.92 percent, and the company left out its two-qubit gate fidelity, reportedly around 97 percent, which is the number that determines whether real algorithms can run. The video's caption also says there is no peer-reviewed paper, which is wrong about the sulfur technique it explains, since that was published in Nature Communications in 2019 at a 75 percent yield rather than the 85 percent the company now claims. Everything about performance comes from the company itself, with no independent testing found, and the machine is currently open for orders rather than confirmed as built and delivered. The underlying manufacturing advance appears genuine; the headline qubit number does not mean what a general audience would assume.
The readings
key figures from the evidencevendor single-qubit fidelity, self-reported, not 99.98% claimed
largest coherent entangled register, smaller than 2019 prior art
two-qubit gate fidelity on predecessor system, omitted from release
Why this verdict
Evidence
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.
Findings
✓ What's accurate 6
- SAXON Q exists, is a 2021 spin-out of Universität Leipzig, and made this announcement on its own official channel on 21 July 2026
- The physics description in the video is broadly correct: NV centers are nitrogen atoms adjacent to a lattice vacancy, initialized optically and controlled with microwaves, and they function at room temperature
- The sulfur co-implantation yield story is real and rests on refereed work, contrary to the caption's "no peer-reviewed paper yet"
- The systems genuinely require no cryogenics, fit a standard server rack and run on ordinary AC power, which is a real architectural difference from superconducting machines
- The company has real deployed hardware accepted by DLR after formal acceptance testing, and a second unit at Fraunhofer IWU
- The vendor does claim the "first to exceed 10 qubits" superlative in exactly those words, so the caption's "says it's built" framing accurately reports what the company said
≈ What's misleading 7
- **Omitted qualifier:** the claim says "more than 10 qubits," which a reasonable listener reads as one machine holding a register of more than ten interacting qubits. The evidence says the 128 figure is an aggregate across 16 classically coordinated cores of 8 entangled qubits each. The largest coherent quantum register the company discloses is 8, which is fewer than the 10-qubit fully connected NV register published in 2019. The qualifier that is missing is the one that carries the entire meaning of the superlative.
- **Marketing as evidence:** the transcript states "Saxon Q just built the first..." as settled fact. Every load-bearing number, the qubit counts, the >85 percent yield, and the fidelity, is vendor self-report with no independent benchmarking found. The caption hedges with "says" and "claim"; the spoken video does not, and the video is what most viewers consume.
- **Fabrication:** the video states 99.98 percent single-qubit fidelity. That figure appears in no source located, including the vendor's own release. The vendor's number is 99.92 percent, and stated as "up to." A 99.92 to 99.98 shift is a quadrupling of implied error-rate performance, from roughly 1 error in 1,250 operations to 1 in 5,000.
- **Benchmark cherry picking:** the single-qubit fidelity is the flattering metric. The two-qubit gate fidelity, reported as 0.97 on the predecessor system in the vendor's own whitepaper table, is the number that governs how deep a useful circuit can run, and it is absent from the release and from the video. Coherence times are also unpublished.
- **Harness mismatch:** "comparable to results from IBM" sets a vendor-reported single-qubit number from one nuclear-spin qubit on a prior-generation machine against a different platform's figures, without matching benchmark protocol, register size, or which gate type is being measured.
- **Unreleased as released:** "just built" and "could just sit under your desk" describe a machine that, as of 25 August 2026, is open for order with delivery quoted within three months for the SXQ128 and from Q2 2027 for the SXQ512. No delivered, independently accepted 128-qubit unit was found.
- **Scale conflation:** the fidelity figure originates on a prior-generation dual-core system, and the accepted field deployments are 4-qubit units, yet both are presented in the same breath as attributes of the new 128-qubit product.
? What's uncertain 6
- Whether any SXQ128 has actually been built and independently verified as a working 128-qubit system. No delivery, acceptance test, or third-party benchmark was found
- The vendor's Gen3 whitepaper was not retrieved directly. The specification table contents, including the 0.97 two-qubit figure, are reported by one secondary analysis and should be read as that analysis's account, not as a retrieved primary specification
- Whether the >85 percent conversion yield claim holds at production scale. The refereed figure is 75.3 percent; the 85 percent number is company-reported and unpublished
- Coherence times (T1/T2) for the new systems, which the company has not disclosed
- Whether the "first to exceed 10 qubits" superlative would survive a full survey of NV-center registers built since 2019, including work by Quantum Brilliance and academic groups. The Delft 10-qubit register is the clearest reference point found, and the vendor's claim is worded to sit just above it
- Pricing, which is not published
Sources
8 of 9 linked to recordsSAXON Q official press release, "SAXON Q Opens Orders for Room-Temperature Quantum Computers Built for the Real World," saxonq.com
Lühmann, John, Wunderlich, Meijer, Pezzagna, "Coulomb-driven single defect engineering for scalable qubits and spin sensors in diamond," *Nature Communications*, 31 Oct 2019
Bradley et al., "A Ten-Qubit Solid-State Spin Register with Quantum Memory up to One Minute," Phys. Rev. X / TU Delft, 2019
PostQuantum analysis, "SAXON Q's 128 Qubits Are Sixteen 8-Qubit Cores," Aug 2026
The Quantum Insider, 21 Jul 2026 (press release carriage)
Quantum Computing Report, 22 Jul 2026
HPCwire, 21 Jul 2026 (off-the-wire release carriage)
Live Science, Aug 2026
SAXON Q Gen3 whitepaper specification table