PSIQUANTUM

Jeremy O'Brien was a professor of physics and electrical engineering at the University of Bristol in England, where he ran one of the world's leading photonic quantum computing labs. He moved to Stanford and co-founded PsiQuantum in 2016 with the contrarian thesis that photonic qubits — individual particles of light — were the only path to a useful, large-scale quantum computer.

His argument: trapped ions and superconducting qubits require exotic, expensive cooling systems and can't scale beyond a few thousand qubits. Photonic qubits work at room temperature and can be manufactured using standard semiconductor fabs.

He convinced GlobalFoundries to partner on manufacturing photonic quantum chips using their existing 300mm silicon fabrication lines.

PsiQuantum is pre-revenue. They're building a million-qubit quantum computer, which they believe will be the first commercially useful fault-tolerant quantum machine.

Their business model will eventually be quantum computing as a service — selling access to their machine for drug discovery, cryptography, materials science, climate modeling, and financial optimization. The partnership with GlobalFoundries means they're manufacturing quantum chips the same way Intel manufactures regular chips, which could give them a massive cost and scale advantage once the technology works.

PsiQuantum is building a photonic quantum computing system based on silicon photonic chips. Their quantum chips use photons as qubits, encoded in properties of light.

They rely on fusion-based quantum computing, where photonic qubits are entangled through a process called "fusion." The key product is the million-qubit fault-tolerant quantum computer they're working toward — not a near-term noisy device but a fully error-corrected machine.

PsiQuantum's strategy is stealth-mode engineering. They've raised $665 million but say almost nothing publicly about their technical progress.

Their growth strategy is not about acquiring customers today — it's about building the first million-qubit quantum computer and then selling access to the most powerful computing resource ever created. The GlobalFoundries partnership is the key strategic move: it means they don't need to build their own fab, which would cost billions more.

PsiQuantum's biggest challenge is that photonic quantum computing is unproven at scale. While the theory is sound, nobody has demonstrated a large-scale fault-tolerant photonic quantum computer.

The company has been relatively secretive about its technical milestones, which some investors and researchers find concerning. They're also in a race against time — other quantum approaches (trapped ions, superconducting) are making rapid progress, and PsiQuantum needs to deliver before the competition catches up.

PsiQuantum has raised from top-tier investors including BlackRock, Microsoft's M12, Baillie Gifford, Blackbird Ventures, and Playground Global. The Australian government committed over $620 million (AUD 940 million) in 2024 to help build PsiQuantum's first large-scale quantum computer in Brisbane.

This is one of the largest government investments in quantum computing globally.