Experimental demonstration of a controlled-NOT wave-packet gate
  We report the experimental demonstration of a controlled-NOT (CNOT) quantum logic gate between motional and internal state qubits of a single ion where, as opposed to previously demonstrated gates, the conditional dynamics depends on the extent of the ion's wave-packet. Advantages of this CNOT gate over one demonstrated previously are its immunity from Stark shifts due to off-resonant couplings and the fact that an auxiliary internal level is not required. We characterize the gate logic through measurements of the post-gate ion state populations for both logic basis and superposition input states, and we demonstrate the gate coherence via an interferometric measurement. 
B. DeMarco, A. Ben-Kish, D. Leibfried, V. Meyer, M. Rowe, B.M.   Jelenkovi\'c, W.M. Itano, J. Britton, C. Langer, T. Rosenba...