quantum computing

Use of particles such as atoms, ions, and photons to perform computations, initally suggested by physicist Richard Feynman in 1982. In 1985, David Deutsch of the University of Oxford described a ‘universal quantum computer’ that would be able to perform feats beyond the capabilities of conventional computers. No such computer has been built to date, but quantum computing is thought to show great promise in certain areas, such as cryptography.

Quantum particles obey the laws of quantum mechanics, which are different from the laws of classical physics. Where a classical bit of information can have two states (1 or 0; on or off), a qubit (quantum bit) has in infinite number of possibilities, and can at the same time be a classical 1 or 0. This is called superposition. Logical operations can be performed on qubits, but when a measurement is performed, superposition is destroyed and the state is reduced to either 1 or 0.