Bonn 2025 – wissenschaftliches Programm
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Q: Fachverband Quantenoptik und Photonik
Q 4: Rydberg Atoms, Ions, and Molecules (joint session Q/MO)
Q 4.5: Vortrag
Montag, 10. März 2025, 12:00–12:15, HS I
Ultralong-Range Ytterbium Rydberg Molecules — •Tangi Legrand, Florian Pausewang, Xin Wang, Ludwig Müller, Eduardo Uruñuela, Wolfgang Alt, and Sebastian Hofferberth — Institute of Applied Physics, University of Bonn, Germany
An ultralong-range Rydberg molecule forms through the interaction between a ground-state atom and the electron of a highly excited Rydberg atom, leading to molecular states characterized by extreme spatial extension, large dipole moments and long lifetimes.
In this work, we present the spectroscopic characterization of such molecules in a dense and ultracold ytterbium (Yb) gas. Using two-photon excitation, we probe the molecular binding energies and map out the vibrational spectra. By applying low-energy quantum scattering techniques to the observed binding energies, we can extract the electron-neutral atom s-wave scattering length. Our data enables precise benchmarking of Yb model wavefunctions derived from multi-channel quantum defect theory, offering a robust validation for the accuracy of theoretical descriptions of Rydberg (molecular) states.
We also present our apparatus featuring a two-chamber compact design comprising a dispenser-loaded 2D MOT and a two-color 3D MOT allowing narrow-linewidth cooling. After loading into an optical trap, we reach T<10 µK at atomic densities of 1013 cm−3. By consecutive evaporation we reach T≈ 200 nK. Electrodes around the atomic cloud allow electric field background compensation, field ionization of Rydberg atoms and molecules, and their delivery to a microchannel plate.
Keywords: Rydberg molecules; Ytterbium; Rydberg atoms