Quantum reality check: meet the 11 teams taking on DARPA’s big challenge
In last week’s newsletter, my colleague Joshua Tall wrote about Google’s latest claim of achieving verifiable quantum advantage. Google’s technology is both impressive and promising, but even with such headline-grabbing news it can still be hard to judge how close we really are to a commercially viable quantum computer. Enter DARPA, the U.S. Defense Advanced Research Projects Agency, which has just announced eleven companies advancing to Stage B of its Quantum Benchmarking Initiative (QBI).
Launched in 2024, the QBI is a program designed to answer one very big question: can we build a truly useful quantum computer by 2033? It’s essentially a rigorous “reality check” on quantum computing: it puts different quantum tech approaches under the microscope to verify whether any of them can achieve utility-scale performance on an economically sensible timeline. The program is not a winner-takes-all competition; multiple teams can succeed in parallel (or none at all). Instead, the focus is on objectively vetting each approach on its own merits.
Stage A saw nearly 20 quantum companies selected to propose fault-tolerant architectures that could realistically be built within a decade and deliver net value. Over six months, DARPA worked closely with each team to rigorously test the feasibility of their concepts.
Stage B comes with funding and scrutiny, and for the selected teams, it’s a chance to prove their tech can go the distance. The Stage B companies, selected from a diverse pool of contenders, now have a year to lay out detailed R&D plans showing how their quantum architectures could scale up and deliver real-world value. The cohort spans everything from trapped ions and superconducting circuits to photonics, silicon spin qubits and neutral atom arrays — a clear signal that no single approach has won out yet.
🧲 Trapped-Ion Qubits
IonQ
– Uses trapped-ion qubits with high-fidelity gates and a scalable architecture. Advanced to Stage B because of its proven real-world performance and credible scaling roadmap.
Quantinuum
– Builds modular trapped-ion systems based on the QCCD (quantum charge-coupled device) architecture. Advanced to Stage B for having a mature roadmap and a de-risked path toward fault tolerance.
❄️ Superconducting Qubits
IBM
– Focuses on superconducting qubits using a modular, chip-linking design. Advanced to Stage B due to a validated fault-tolerant architecture and a detailed scaling plan.
Nord Quantique
– Works on bosonic error-correcting codes implemented in superconducting cavities. Advanced to Stage B for its unique and hardware-efficient approach to error correction.
💡 Photonic Quantum Computing
Photonic Inc.
– Develops silicon spin qubits connected through photonic interconnects. Advanced to Stage B for its distinctive distributed architecture that uses optical entanglement.
Xanadu
– Uses photonic qubits generated from squeezed light and controlled in optical circuits. Advanced to Stage B thanks to a credible, fault-tolerant photonic roadmap with defined execution milestones.
🔃 Silicon-Based Spin Qubits
Diraq
– Builds CMOS-compatible silicon spin qubits in quantum dots. Advanced to Stage B for offering the most scalable and cost-effective silicon-based design.
Quantum Motion
– Works on CMOS-based silicon spin qubits integrated with cryo-CMOS control electronics. Advanced to Stage B for providing a plausible pathway to a fully CMOS-compatible quantum chip.
Silicon Quantum Computing
– Creates atomically engineered donor qubits in silicon. Advanced to Stage B because of its atomic-precision fabrication and high algorithmic fidelity.
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⚛️ Neutral Atom Arrays
Atom Computing
– Uses neutral atoms with long-lived nuclear spin qubits arranged in optical lattices. Advanced to Stage B for its high-coherence atomic arrays and credible scaling strategy.
QuEra Computing Inc.
– Develops neutral atoms trapped in optical tweezers with Rydberg interactions. Advanced to Stage B for its scalable, energy-efficient platform supported by a strong experimental foundation.
Going forward, success in Stage B will mean delivering a detailed, credible blueprint for a 2033-era quantum computer and demonstrating (via intermediate prototypes or simulations) that there are no critical obstacles left unaddressed. Crucially, DARPA’s support in Stage B includes independent verification and validation from expert teams, which will scrutinize whether the proposed performance targets and risk mitigations are realistic.
Those teams that satisfy the Stage B objectives will be invited into Stage C, where the real proof comes: building and testing the components and subsystems to show that the envisioned machine can actually be constructed and will perform as expected.
Through this next phase, the quantum community – and observers in government, industry, and academia – will gain much-needed insight into which quantum computing approaches are most likely to deliver a useful, fault-tolerant system within the next decade. The initiative provides a rigorous framework to separate “signal from noise” in quantum computing, holding each approach accountable to the ultimate benchmark: can it solve real problems at scale, and is it worth the cost?
As the QBI unfolds into maturity, the next year could be pivotal in shaping the future of quantum computing — and in showing which paths might actually lead us there.
Written by Josh Blunsden , Mewburn Ellis Patent Technical Assistant.
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A nice overview, thank you!!!!! My money is on photonic QC or silicon-based QC. It feels terrible saying this in a year where the Nobel Prize in physics was awarded in relation to Josephson junctions. In any event, exciting times.