In 1985, David Deutsch, one of the pioneers of this area, published a landmark paper in quantum computation, “Quantum theory, the Church-Turing principle and the universal quantum computer.” In this paper he described quantum computers and how they differed from conventional computers. The question was whether quantum computers were more computationally powerful than traditional computers. It took some time, but the conclusion was that they were not.

— Chris Bernhardt, Turing’s Vision