A SILICON-BASED NUCLEAR-SPIN QUANTUM COMPUTER

Quantum computers promise to exceed the computational efficiency of or dinary classical machines because quantum algorithms allow the executi on of certain tasks in fewer steps. But practical implementation of th ese machines poses a formidable challenge. Here I present a scheme for implementing a quantum-mechanical computer. Information is encoded on to the nuclear spins of donor atoms In doped silicon electronic device s. Logical operations on individual spins are performed using external ly applied electric fields, and spin measurements are made using curre nts of spin-polarized electrons. The realization of such a computer is dependent on future refinements of conventional silicon electronics.