Paul Benioff

A physicist at Argonne National Laboratory who became interested in what it would mean for a computer to be a physical system obeying quantum laws.

In 1980 he published a model in which a Turing machine, the standard abstract computer, is written as a quantum Hamiltonian, with its steps carried out by unitary evolution. It was not yet a computer that could do something faster than a classical one, but it was the first proof that quantum mechanics does not forbid computation.

Before Benioff, one could fairly ask whether quantum mechanics could even support a computer that does its own bookkeeping. His model answered yes, and paved the way for Feynman's and Deutsch's more ambitious ideas.