In 1994 Peter Shor 65] published a factoring algorithm for a quantum computer that finds the prime factors of a composite integer N more efficiently than is possible with the known algorithms for a classical com- puter.
Since the difficulty of the factoring problem is crucial for the se- curity of a public key encryption system, interest (and funding) in quan- tum computing and quantum computation suddenly blossomed.
Quan- tum computing had arrived.
The study of the role of quantum mechanics in the theory of computa- tion seems to have begun in the early 1980s with the publications of Paul Benioff 6]' 7] who considered a quantum mechanical model of computers and the computation process.
A related question was discussed shortly thereafter by Richard Feynman 35] who began from a different perspec- tive by asking what kind of computer should be used to simulate physics.
His analysis led him to the belief that with a suitable class of quantum machines one could imitate any quantum system.
Birkhauser An introduction to quantum computing algorithms, paperback/arthur o. pittenger
