Dresden 2011 – scientific programme

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Q: Fachverband Quantenoptik und Photonik

Q 32: Quantum Information: Atoms and Ions 3

Q 32.2: Talk

Wednesday, March 16, 2011, 14:45–15:00, HÜL 386

Quantum information processing with trapped ions at NIST — •Christian Ospelkaus — NIST, 325 Broadway, Boulder, CO, USA — Present address: QUEST, Universität Hannover, Welfengarten 1, 30167 Hannover and PTB, Bundesallee 100, 38116 Braunschweig

Most current schemes for Quantum Information Processing (QIP) with trapped ions implement quantum logic gates through a laser-induced spin-dependent interaction between ions held in the same trap. We give an overview of the current effort and describe experiments which explore ideas beyond these well-established techniques. In particular, we demonstrate Coulomb coupling between two ions held in individual traps separated by 40 µm. We observe oscillations of energy between the two oscillators at the single quantum level. Beyond the fundamental relevance of this system of coupled quantized mechanical oscillators, these results open new experimental perspectives for quantum simulation, novel entangling schemes for QIP and for precision spectroscopy. In a second experiment, we demonstrate a microwave near-field approach to coherent quantum control of trapped ions. For quantum logic, this approach has several important potential advantages with respect to operation fidelity and reduced complexity. We demonstrate single-qubit rotations with π times of less than 20 ns, driven by microwave currents in the trap electrodes, motional sideband transitions induced by the near-field magnetic field gradient, and sideband cooling. We discuss applications to quantum logic, simulation and spectroscopy. This work has been supported by IARPA, DARPA, NSA, ONR, and the NIST Quantum Information Program.