Quantum Computing History

When quantum computers were first proposed in the 1970s and 1980s (by theorists such as the late Richard Feynman of California Institute of Technology, Pasadena, Calif.; Paul Benioff of Argonne National Laboratory in Illinois; David Deutsch of Oxford U. in England., and Charles Bennett of IBM's T.J. Watson Research Center, Yorktown Heights, N.Y.), many scientists doubted that they could ever be made practical. But in 1994, Peter Shor of AT&T Research described a specific quantum algorithm for factoring large numbers exponentially faster than conventional computers -- fast enough to defeat the security of many public-key cryptosystems. The potential of Shor's algorithm stimulated many scientists to work toward realizing the quantum computers' potential. Significant progress has been made in recent years by numerous research groups around the world.

While at IBM, Chuang extended his reputation as one of the world's leading quantum computing experimentalist. He led the team that demonstrated the world's first 2-qubit quantum computer (in 1998 at University of California Berkeley). At IBM-Almaden, Chuang and colleagues were first to demonstrate important quantum computing algorithms -- Grover's database-search algorithm in 1999 with a 3-qubit quantum computer and order finding last year (August 2000) with a 5-qubit quantum computer. The factorization using Shor's algorithm announced today is the most complex algorithm yet to be demonstrated by a quantum computer.

In addition to its ambitious experimental program, IBM Research is also noted for its many theoretical contributions to the emerging field of quantum information. IBM scientists pioneered quantum cryptography, quantum communications (including the concept of quantum teleportation) and efficient methods of error correction. David DiVincenzo, research staff member at IBM's Watson lab, has promulgated the five criteria necessary for a practical quantum computer:

1. a scalable physical system with well-characterized qubits;
2. the ability to initialize the qubit state;
3. decoherence times much longer than the quantum gate operation time;
4. a universal set of quantum gates; and
5. the ability to measure specific qubits