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Q: Fachverband Quantenoptik und Photonik
Q 32: Quantum Information: Atoms and Ions 3
Q 32.3: Talk
Wednesday, March 16, 2011, 15:00–15:15, HÜL 386
High precision measurement techniques for improving the scalability of ion trap quantum computing — •Andreas Walther, Ulrich Poschinger, Frank Ziesel, Max Hettrich, Alex Wiens, Michael Schnorr, Jens Welzel, Kilian Singer, and Ferdinand Schmidt-Kaler — Institute of Physics, University of Mainz, Staudinger Weg 7, 55128 Mainz
Two techniques for advancing the state of quantum computing in ion traps are presented. Both results are important for improving future gate fidelities as well as scalability possibilities of the ion trap quantum computing concept. The first one is a novel homodyne detection of the interference between two parts of an ion wavepacket, where the motional state of the ion is entangled with its spin state. We use this technique to characterize the phase space trajectory of the ion with high enough accuracy to find deviations from the linear approximation to the spin dependent light force, leading to an extension of the current models of the system evoloution.
Secondly, we employ a single ion to measure a magnetic field gradient with a relative sensitivity of Δ B/B ∼ 10−7 over a 100 µ m distance, which is shown to be quantum shot noise limited. The compensation of gradients helps to increase the coherence time of qubits that are transported for the realization of scalable quantum information processsing.