MilestoneTheory & algorithmsConfirmed

Researchers propose quantum computing with ensembles of nuclear spins

Nov 1996

David Cory, Amr Fahmy and Timothy Havel present an NMR computing proposal at PhysComp96 in November 1996; Neil Gershenfeld and Isaac Chuang publish an independent proposal in Science in January 1997. Both use nuclear spins in large collections of molecules to carry out quantum computation.

Why it matters

NMR ran the first small quantum algorithms, but its signal weakens rapidly as qubits are added, which kept these machines small.

David Cory · Amr Fahmy · Timothy Havel · Neil Gershenfeld · Isaac Chuang · MIT · Harvard

See it on the timeline

First quantum algorithms run on small NMR quantum computers (Jan 1998)
Researchers demonstrate quantum error correction in the lab (Feb 6, 1998)

Sources (6)

MIT (Timothy F. Havel) Ensemble Quantum Computing by NMR Spectroscopy
Primary source

“extended abstract, PhysComp96 Proceedings, November 1996, New England Complex Systems Inst.”
MIT (Timothy F. Havel) Ensemble Quantum Computing by NMR Spectroscopy (measurement)
Primary source

“ensemble averaging over the distribution of microscopic observations.”
MIT Center for Bits and Atoms Bulk Spin Resonance Quantum Computation — author publication list
Primary source

“Bulk Spin Resonance Quantum Computation Neil A. Gershenfeld and Isaac L. Chuang, Science275, pp. 350-356 (1997).”
MIT (Timothy F. Havel) Ensemble Quantum Computing by NMR Spectroscopy — PNAS publication and scaling
Primary source

“Thus our present methods of preparing pseudo-pure states from thermal equilibrium states by averaging all but one of the populations to equality results in an exponentially decreasing the signal-to-noise in the corresponding spectrum.”
Proceedings of the National Academy of Sciences Ensemble quantum computing by NMR spectroscopy
Primary sourceMar 4, 1997

“We present a new computational model, which differs from a QC only in that the result of a measurement is the expectation value of the observable, rather than a random eigenvalue thereof.”
Proceedings of the National Academy of Sciences Ensemble quantum computing by NMR spectroscopy — independent proposals
Primary sourceMar 4, 1997

“Gershenfeld and Chuang also presented many of the same ideas described in this paper at the workshop cited in ref. 12 and have recently published a paper on the subject (20).”

Added Oct 24, 2026 · Updated Oct 24, 2026. Spotted an error? Tell us and we will review it.

Researchers propose quantum computing with ensembles of nuclear spins

Why it matters

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