- Four-qubit operation took 14.8 microseconds.
What changed
Researchers at the University of Pennsylvania report a diamond experiment that creates a four-qubit entangled state in 14.8 microseconds. The September 14 journal paper describes a parallel gate acting through a nitrogen-vacancy centre, rather than a sequence of pairwise operations. Reported gate fidelity was 0.92, compared with 0.69 for the sequential approach.
Why it matters
The comparison points to a practical control problem: performing operations together can reduce the time and interference involved in assembling entanglement. This could help researchers design more efficient small quantum registers.
What remains unproven
The experiment does not establish a scalable, fault-tolerant computer. Extension to larger registers and other materials remains prospective. A preprint appeared in 2025; the current milestone is peer-reviewed publication.
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Recorded source-check date: 15 Sep 2026. A link is not, by itself, evidence that every claim has been independently verified.
Changes & version history
Version 3 · 15 Sep 2026
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Version 2 · 15 Sep 2026
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Version 1 · 15 Sep 2026
Source-linked private review edition