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Q: Fachverband Quantenoptik und Photonik

Q 26: Quantum Information: Atoms and Ions 2

Q 26.7: Vortrag

Mittwoch, 16. März 2011, 12:15–12:30, HÜL 386

Quantum computing with magnetic field insensitive dressed states — •I. Baumgart¹, N. Timoney¹, A. Retzker², A.F. Varón¹, M. Johanning¹, M. Plenio², and C. Wunderlich¹ — ¹Fachbereich Physik, Universität Siegen, 57068 Siegen — ²Institute of Theoretical Physics, Universität Ulm, 89069 Ulm

Ion trap quantum computing or quantum simulations with easy to control and stable microwave sources instead of complex laser systems, require the use of Zeeman sub levels. Here, dephasing between magnetic field sensitive states, due to ambient magnetic field noise, shortens the coherence. By dressing magnetic field sensitive states with microwave fields we demonstrate theoretically and experimentally that the dressed states are long-lived and that fast universal quantum logic is possible with this approach. Experimentally we achieved, depending on the particular dressed state, an extension in coherence times between a factor of 4 and two orders of magnitude compare to bare states.

Using rf coupling, a dressed state and a magnetic field insensitive bare state can be used as a qubit. Multi-qubit gates can be very fast, since the carrier transition cancels by interference when tuning to a motional sideband. The advantage over the regular quantum computing scheme is that fast gates are possible even when the Lamb Dicke parameter is small.