Experimental demonstration of a technique to generate arbitrary quantum   superposition states
  Using a single, harmonically trapped $^9$Be$^+$ ion, we experimentally demonstrate a technique for generation of arbitrary states of a two-level particle confined by a harmonic potential. Rather than engineering a single Hamiltonian that evolves the system to a desired final sate, we implement a technique that applies a sequence of simple operations to synthesize the state. 
A. Ben-Kish, B. DeMarco, V. Meyer, M. Rowe, J. Britton, W.M. Itano,   B.M. Jelenkovi\'c, C. Langer, D. Leibfried, T. Rosenba...