Heidelberg 2015 – scientific programme
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Q: Fachverband Quantenoptik und Photonik
Q 51: Ultracold Atoms: Trapping and Cooling I (with A)
Q 51.1: Group Report
Thursday, March 26, 2015, 11:00–11:30, P/H2
Isospaced ion crystals and fault-tolerant Hahn-Ramsey interferometry — •Michael Johanning1, Timm F. Gloger1, Peter Kaufmann1, Delia Kaufmann1, Thomas Collath1, M. Tanveer Baig1, Nikolay V. Vitanov2, and Christof Wunderlich1 — 1Faculty of Science and Technology, Department of Physics, University of Siegen, Walter Flex Str. 3, 57072 Siegen, Germany — 2Department of Physics, St Kliment Ohridski University of Sofia, 5 James Bourchier blvd, 1164 Sofia, Bulgaria
We describe the static and dynamic properties of strings of ions stored in segmented electrodynamical Paul traps with a uniform ion separation achieved by an anharmonic effective potential generated by suitable voltages applied to segmented dc electrodes or by appropriate electrode shaping. We find expressions for the desired potential and calculate normal modes and the effective spin coupling when the ion string is exposed to a magnetic gradient. The effect on the radial confinement and the transition of the equidistant linear chain to an almost equidistant zigzag are investigated.
In the second part, a scheme for efficient correction of driving field frequency drifts in Ramsey interferometry is presented. The two near-resonant π/2 pulses of duration T used in the traditional Ramsey setup are supplemented with an additional refocussing pulse of duration 2T and opposite detuning. We demonstrate the validity of the concept by comparing experimental results from plain Ramsey and Hahn-Ramsey measurements, obtained from microwave spectroscopy on 171Yb+ ions in a segmented linear Paul trap.