Caltech, 1983. John Preskill is a young physicist, newly arrived in Pasadena. Richard Feynman is still there, moving through the halls, talking physics.
They overlap for five years. Preskill later said they talked a fair amount about science, especially subnuclear particles. Feynman had also been thinking about something much stranger. Ordinary computers were terrible at simulating the quantum world. Maybe the answer was to build a computer that was itself quantum.
His paper “Simulating Physics with Computers” had appeared the year before Preskill arrived.
More than forty years later, Preskill holds the Richard P. Feynman Professorship of Theoretical Physics at Caltech. Quantum computing has become one of the central threads of his life.
He started in particle physics, cosmology and gravitation. By the 1990s, his attention had shifted toward quantum information and one of the field’s most stubborn problems: how to keep quantum information intact long enough to actually use it.
With Daniel Gottesman and others, Preskill helped develop the theory of fault tolerant quantum computation. He also pushed quantum information into places that once seemed far removed from computing, including black holes, quantum gravity and the structure of spacetime.
In 2000, Preskill and Jeff Kimble helped create Caltech’s Institute for Quantum Information. It later became part of the Institute for Quantum Information and Matter. His quantum computation notes, online since 1997, became required reading for a generation of physicists.
Then came NISQ. Noisy Intermediate Scale Quantum. Preskill coined the term for the awkward stage we are still in now, with quantum machines powerful enough to matter and still far too noisy to do everything people hope they eventually will.
He remains at Caltech and is also helping build what comes next. In 2026, Preskill became part of the founding team of Oratomic, a Pasadena quantum computing company working on fault tolerant machines using neutral atoms, light and more efficient error correction.
There is something I like about the symmetry of it.
Preskill arrives at Caltech with Feynman still down the hall, thinking about quantum computers before almost anyone else is.
Four decades later, Preskill is still there, still working on the same impossible sounding idea.
