Freiburg 2019 – scientific programme
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FM: Fall Meeting
FM 57: Quantum Sensing: Spectroscopy I
FM 57.4: Talk
Wednesday, September 25, 2019, 15:00–15:15, 2006
Robust optical clock transition in 40Ca+ by dynamical decoupling — •Lennart Pelzer1, Kai Dietze1, Ludwig Krinner1, Stephan Hannig1, Nicolas Spethmann1, Nati Aharon2, Alex Retzker2, Tanja E. Mehlstäubler1, and Piet O. Schmidt1,3 — 1QUEST Institute for Experimental Quantum Metrology, Physikalisch-Technische Bundesanstalt, 38116 Braunschweig, Germany — 2Racah Institute of Physics, The Hebrew University of Jerusalem, Jerusalem 91904, Israel — 3Leibniz Universität Hannover, 30167 Hannover, Germany
Optical clocks based on single trapped ions are hindered by long averaging times caused by the quantum projection noise-limited statistical uncertainty. Long probe times on the order of many seconds would significantly reduce the statistical uncertainty. However, currently the phase coherence of available laser systems limits the probe time. We propose to improve the phase coherence of a laser by stabilizing it to a transition in a multi-ion crystal with a large signal-to-noise ratio. Relevant frequency shifts in a crystal of several hundred 40Ca+ ions are canceled by employing a continuous dynamical decoupling scheme. Both Zeeman manifolds of the S1/2 ↔ D5/2 clock transition in 40Ca+ get doubly-dressed by four tailored driving RF-fields to form a robust optical clock transition, essentially free of homogeneous magnetic field and inhomogeneous electric quadrupole and tensor polarizability shifts as well as shifts due to amplitude fluctuations in the driving fields. Experimental results implementing this scheme in our segmented Paul-trap setup will be presented.