Freiburg 2024 – scientific programme

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A: Fachverband Atomphysik

A 26: Poster V

A 26.10: Poster

Wednesday, March 13, 2024, 17:00–19:00, Tent C

High-performance optical clocks based on ¹⁷¹Yb⁺ — Martin Steinel, Melina Filzinger, •Saaswath JK, Jian Jiang, Ekkehard Peik, and Nils Huntemann — Physikalisch-Technische Bundesanstalt, Braunschweig, Germany

Optical clocks based on narrow-linewidth electronic transitions of trapped ions are employed in various high-precision experiments probing the limits of our current understanding of physics. The ¹⁷¹Yb⁺ ion is particularly suited to these measurements, because it provides two transitions with large sensitivity to variations of fundamental constants and low sensitivity to external perturbations. Comparisons of its ²S_1/2−²D_3/2 electric quadrupole (E2) and ²S_1/2−²F_7/2 electric octupole (E3) transition currently provide most stringent limits on potential variations of the fine structure constant and constrain the coupling between normal matter and ultra-light dark matter.

The systematic uncertainty of high-performance ¹⁷¹Yb⁺ optical clocks operated at room temperature has so far been limited by the uncertainty in the sensitivity of the transitions to thermal radiation Δ α. For the ⁸⁸Sr⁺ ion, Δ α has been measured with significant lower uncertainty. We employ this by using the ⁸⁸Sr⁺ as a temperature sensor and determine it’s clock transition frequency with record accuracy. In addition, we calibrate the intensity of an infrared laser with a single ⁸⁸Sr⁺ ion. Measurements of the induced frequency shift of an ¹⁷¹Yb⁺ ion at the same position in the beam provides the corresponding Δ α. This way, we largely reduce the uncertainty achievable with ¹⁷¹Yb⁺ ion clocks.

Keywords: Optical clocks; Trapped ions; Frequency comb; New physics; Ytterbium spectroscopy