What are spin qubits?

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IBM announced it has signed a definitive agreement to acquire HRL Laboratories, a joint Boeing-GM R&D institution with deep expertise in silicon-spin qubit engineering. IBM frames the deal as additive to — not a replacement for — its superconducting qubit roadmap, citing shared silicon fabrication infrastructure as the key compatibility factor. The technical rationale centers on an alternative approach to quantum information. Spin qubits exploit the spin state of individual electrons — either up or down, mapping to 0 and 1 — confined in quantum dots. HRL builds its quantum dots from silicon-germanium (SiGe) layers using standard chip fabrication, the same foundry technology IBM already uses for superconducting systems. HRL's 'exchange only' architecture assigns three electrons across three quantum dots per qubit, sidestepping the precision challenges of single-electron control. IBM's stated long-term goal is a quantum computing internet, and it believes both superconducting and spin qubit modalities can contribute. For now, superconducting qubits remain IBM's production focus; spin qubits represent architectural optionality for future scaling generations. For AI practitioners, near-term impact is minimal — quantum computing remains pre-commercial for most workloads. The deal matters most to teams tracking long-horizon compute infrastructure: IBM is now explicitly hedging with two qubit technologies where previously it had one.