SAMOP 2023 – scientific programme
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Q: Fachverband Quantenoptik und Photonik
Q 70: Precision Measurements: Atom Interferometry II (joint session Q/A)
Q 70.6: Talk
Friday, March 10, 2023, 15:45–16:00, F342
Applications of tuneable interactions in atom interferometry sources — •Alexander Herbst, Henning Albers, Wei Liu, Knut Stolzenberg, Sebastian Bode, Ernst M. Rasel, and Dennis Schlippert — Leibniz Universität Hannover, Institut für Quantenoptik
Atom interferometers are powerful tools for precision measurements in fundamental physics or applications such as inertial sensing. Fundamentally, the sensitivity of these devices is limited by shot noise, thus motivating high-flux atomic sources. Furthermore, control over the ensemble’s initial conditions and its expansion dynamics is key for systematic error mitigation.
To address these challenges we demonstrate a high flux source of ultra-cold 39K with nearly Heisenberg limited expansion rates in the horizontal plane. Due to its broad Feshbach resonances at comparably low magnetic fields 39K allows for changing its atomic interactions without the need for complex coil setups. By dynamically tuning its scattering length along the evaporation trajectory we achieve quantum degeneracy in below 200 ms evaporation time, maintaining a constant flux. Subsequently, changing the scattering length to a minimal positive value reduces the mean-field energy, thus offering a simple and robust way to decrease the expansion rate to an effective temperature equivalent of a few nanokelvin. Moreover, our method can also be applied to improve more complex techniques such as matter-wave lensing, allowing for effective temperatures in the sub-nK regime.