Hannover 2010 – scientific programme
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SYDC: Symposium Decoherence in the light of modern experiments
SYDC 1: Decoherence in the Light of Modern Experiments I
SYDC 1.2: Invited Talk
Tuesday, March 9, 2010, 14:30–15:00, E 415
Fighting Decoherence: Quantum Information Science with Trapped Ca+ Ions — T. Monz1, K. Kim1, A. Villar1, P. Schindler1, M. Chwalla1, M. Riebe1, C. F. Roos2, H. Häffner2, W. Hänsel1,2, M. Hennrich1, and •R. Blatt1,2 — 11Institut für Experimentalphysik, Universität Innsbruck, Technikerstraße 25, A-6020 Innsbruck, Austria — 2Institut für Quantenoptik und Quanteninformation, Österreichische Akademie der Wissenschaften, Otto-Hittmair-Platz 1, A-6020 Innsbruck, Austria
Trapped strings of cold ions provide an ideal system for quantum information processing. The quantum information can be stored in individual ions and these qubits can be individually prepared; the corresponding quantum states can be manipulated and measured with nearly 100% detection efficiency. With a small ion-trap quantum computer based on up to eight trapped Ca+ ions as qubits we have generated genuine quantum states in a pre-programmed way. In particular, we have generated GHZ and W states in a fast and scalable way and we have demonstrated the three-qubit Toffoli gate with trapped ions which is analyzed via state and process tomography. High fidelity CNOT-gate operations were investigated towards fault-tolerant quantum computing. All protocols require either avoiding decoherence using appropriate experimental conditions or tailoring decoherence free subspaces. With logical qubits encoded in two physical qubits the universal operations for quantum information processing were demonstrated within a decoherence free subspace [1].
[1] T. Monz et al., Phys. Rev. Lett. 103, 200503 (2009)