Implementation of Grover's Quantum Search Algorithm in a Scalable System
  We report the implementation of Grover's quantum search algorithm in the scalable system of trapped atomic ion quantum bits. Any one of four possible states of a two-qubit memory is marked, and following a single query of the search space, the marked element is successfully recovered with an average probability of 60(2)%. This exceeds the performance of any possible classical search algorithm, which can only succeed with a maximum average probability of 50%. 
K.-A. Brickman, P. C. Haljan, P. J. Lee, M. Acton, L. Deslauriers, C.   Monroe