SAMOP 2023 – scientific programme

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Q: Fachverband Quantenoptik und Photonik

Q 50: Quantum Gases: Fermions I

Q 50.1: Talk

Thursday, March 9, 2023, 11:00–11:15, F342

Collective excitations in mesoscopic Fermi gases — •Philipp Lunt, Paul Hill, Johannes Reiter, Philipp Preiss, and Selim Jochim — Physikalisches Institut, Universität Heidelberg

Understanding the elementary excitations of strongly interacting many-body systems in terms of the independent motion of individual particles and their collective behaviour has been a central theme in many fields ranging from nuclear physics to cold atoms [1,2].

Here, we present a study of elementary excitations of a mesoscopic Fermi system across the BEC-BCS crossover by means of spectroscopic probes. Therefore, we use an established spilling technique [3] to prepare a balanced system of few fermionic atoms in a tightly confined tweezer. We excite the quadrupole mode by interference with a Laguerre-Gaussian mode. Tuning of the interparticle interactions via a broad Feshbach resonance allows us to observe the transition from single-particle to collective excitations. Furthermore, we investigate the breakdown of collectivity by reducing the atom number gradually.

[1] B. Mottelson Science 193 (4250), 287-294 (1976) [2] S. Giorgini et al. Rev.Mod.Phys. 80, 125 (2008) [3] F. Serwane et al. Science 332 (6027), 336-338 (2011)