Mainz 2026 – scientific programme

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A: Fachverband Atomphysik

A 16: Ultracold Matter IV – Bosons, Rydberg Systems, and Others (joint session Q/A)

A 16.5: Talk

Wednesday, March 4, 2026, 15:30–15:45, P 2

Tuning the Effective Range via Periodic Driving — •Sejung Yong and Axel Pelster — Department of Physics, RPTU Kaiserslautern-Landau, Germany

Combining Floquet physics with Feshbach resonances leads to dynamically created scattering resonances, which can physically be identified as Floquet bound states [1]. Experimentally these emerging Floquet-Feshbach resonances turned out to be observable via particle loss spectroscopy [2]. Thus, periodic driving allows now an unprecedented level of control for both resonance position and width for the s-wave scattering length. Here we extend the Floquet-Feshbach analysis by systematically taking the lowest energy-dependence of the scattering amplitude into account. With this we find how periodic driving changes the underlying effective range, which may have consequences for nonuniversal effects in ultracold quantum gases [3]. Exemplarily we show that a monochromatic drive of a broad magnetic Feshbach resonance yields a narrow Floquet-Feshbach resonace. [1] C. Dauer, A. Pelster and S. Eggert, Phys. Rev. Lett. 135, 033402 (2025). [2] A. Guthmann, F. Lang, L. M. Klein, S. Barbosa, and A. Widera, Sci. Adv. 11, 10 (2025). [3] N. Kaschewski, A. Pelster, and C.A.R. Sá de Melo, Phys. Rev. Res. 7, 033186 (2025).

Keywords: Feshbach resonance; Floquet physics; scattering length; effective range