EXPERIMENTAL IMPLEMENTATION OF FAST QUANTUM SEARCHING

Using nuclear magnetic resonance techniques with a solution of chlorof orm molecules we implement Grover's search algorithm for a system with four states. By performing a tomographic reconstruction of the densit y matrix during the computation good agreement is seen between theory and experiment. This provides the first complete experimental demonstr ation of loading an initial state into a quantum computer, performing a computation requiring fewer steps than on a classical computer, and then reading out the final state.