Bonn 2025 – wissenschaftliches Programm
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Q: Fachverband Quantenoptik und Photonik
Q 20: Atom & Ion Clocks and Metrology I
Q 20.3: Vortrag
Dienstag, 11. März 2025, 11:45–12:00, HS Botanik
Clock comparisons with an aluminium ion clock at the 10−17 level — •Fabian Dawel1,2, Derwell Drapier1, Lennart Pelzer1, Vincent Barbé1, Kai Dietze1,2, Marek Hild1,2, Johannes Kramer1,2, and Piet O. Schmidt1,2 — 1Physikalisch-Technische Bundesanstalt, 38116 Braunschweig, Germany — 2Leibniz Universität Hannover, 30167 Hannover, Germany
The SI second is defined by a hyperfine transition in caesium. Currently it is discussed to redefine the second using optical frequency standards with lower statistical and systematic uncertainty. One criterion for the redefinition is the agreement of measured frequency ratios from different institutes at a level of <5×10−18 , to validate the frequency uncertainty budgets. Here, we present frequency ratio measurements of an aluminium ion clock. For the measurement we use a Ramsey interrogation time of 300 ms, while simultaneous sympathetically cooling via a co-trapped calcium ion. Electromagnetic transparency (EIT) cooling cools all six motional modes close to the motional ground state and keeps the time dilation shift independent from the probe time. Using EIT cooling during interrogation induces a light shift on the clock transition. With calcium as a sensor, we can measure the electric field of the cooling lasers and evaluate the systematic frequency uncertainty of the aluminium ion. We compared our clock against a 87Sr lattice clock and a 171Yb+ ion clock and measure the ratios.
Keywords: Optical clock; Aluminium clock; Quantum logic spectroscopy; Frequency ratio; SI second