Erlangen 2022 – scientific programme
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A: Fachverband Atomphysik
A 30: Precision Measurements and Metrology II (joint session Q/A)
A 30.12: Poster
Thursday, March 17, 2022, 16:30–18:30, P
Correlation spectroscopy on a 40Ca+ two ion system for optical atomic clocks — •Kai Dietze1,2, Ludwig Krinner1,2, Lennart Pelzer1,2, Fabian Dawel1,2, Johannes Kramer1,2, Nicolas Spethmann1,2, and Piet O. Schmidt1,2 — 1QUEST Institute for Experimental Quantum Metrology, Physikalisch Technische Bundesanstalt, 38116 Braunschweig — 2Leibniz Universität Hannover, 30167 Hannover
Time and Frequency are the most accurately determined physical quantities. Though for optical clocks based on trapped ions like 40Ca+ the reachable statistical uncertainty is limited by the interrogation time due to decoherence processes and a low signal-to-noise ratio (SNR). Both can be significantly enhanced by employing correlated interrogation techniques within a decoherence-free subspace (DFS) of multiple ions. We utilize Bell-states of opposing magnetic quantum numbers to create a two-particle state whose phase evolution is independent of the ambient magnetic field. Using a pair of fully entangled ions the SNR of this measurement technique can even surpass the standard-quantum-limit (SQL). In our experiments, the correlation of both ions within a Ramsey-interferometer is used to disseminate the differential phase evolution against our clock laser. We present measurements showing the preparation of entangled and correlated two-ion states, demonstrating the increased interrogation time as well as first results showing the potential of the correlation spectroscopy used in an optical atomic clock.