In March 2026, a consortium in Denver assembled a working quantum computer from five different vendors’ components in five months. A Dutch QPU, Dutch control electronics, an American cryostat, Australian calibration software, and a global supply chain partner, integrated into a cloud-accessible machine for under $8 million. A year earlier, the same capability would have required a $50 million commitment to a single vertically integrated vendor.

That build proved a thesis: quantum computers can now be assembled the way servers, aircraft, and data centers are assembled, from independently sourced, best-of-breed components managed by a systems integrator. The Quantum Open Architecture (QOA) model has moved from concept to operational reality.

At the same time, governments worldwide committed billions to quantum manufacturing rather than quantum research. The money is flowing. The components exist. But no book tells a CTO, laboratory director, or defense procurement officer what they need to know to act. Quantum Systems Integration was written for that gap. Inside, you will find:

How the Quantum Open Architecture model works in practice. The six-layer stack, the vendors at each layer, and why disaggregation rewrites the procurement calculus for every buyer evaluating quantum compute hardware.

What it takes to build a superconducting quantum computer from modular components. The signal chain from room temperature to 10 millikelvin, the cryostat selection, the control electronics, the cabling, and the calibration software that cuts bring-up from months to weeks.

How trapped-ion, neutral-atom, photonic, and silicon-spin builds differ. Facility requirements, vendor options, integration timelines, and where each modality fits in the procurement decision.

What a quantum computer actually costs. Capital expenditure tiers from $2 million to $150 million, line-item breakdowns, five-year total cost of ownership models, and the personnel costs that catch every first-time buyer off guard.

The supply chain constraints that set your timeline. Helium-3 structural deficits, cryogenic I/O density limits, dilution refrigerator lead times, and FPGA allocation bottlenecks.

How to integrate quantum compute resources with existing HPC infrastructure using NVQLink, QRMI, and Slurm-native scheduling, and why the Western quantum software stack is a strategic vulnerability.

A step-by-step integration sequence from procurement to first qubit signal, including facility preparation, the OCP QPU Deployment Checklist, commissioning procedures, and SLA acceptance criteria.

Government funding programs across 15+ countries. How to structure applications, which programs fund hardware versus research, and how to align procurement timelines with grant cycles.

Written from over 25 years of building quantum ventures (including Boston Photonics and PQ Defense) and advising governments and enterprises on quantum technology strategy. This is the builder’s guide from someone who has done the work, not theory from the sidelines.