Hannover 2020 – scientific programme

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A: Fachverband Atomphysik

A 28: Poster Session - Atomic Physics IV

A 28.15: Poster

Thursday, March 12, 2020, 16:00–18:00, Empore Lichthof

Emergence of the Higgs mode in a two-dimensional few-fermion system — •Keerthan Subramanian, Luca Bayha, Marvin Holten, Ralf Klemt, Philipp Preiss, and Selim Jochim — Physikalisches Institut, Universität Heidelberg, 69120 Heidelberg, Germany

Knowledge of collective excitations is indispensable for many-body systems since they can be used to determine the low-energy properties of the system while being completely ignorant of the dynamics of microscopic constituents. But how many constituents does a system have to contain to be considered many-body?
To gain an insight into this question, we study excitations of an ultracold few-fermion system consisting of ⁶Li atoms. We first deterministically prepare few atoms in closed shell configurations of a 2D harmonic trapping potential and then excite the system by modulating interactions. We find that the lowest monopole mode shows a non-monotonic behavior and is composed predominantly of pair-excitations prescient of Higgs mode in the many-body limit. This resemblance to the Higgs mode becomes more striking with increasing particle number as more shells of the 2D harmonic oscillator are populated. We further find that the precursor to the Higgs mode can be coherently driven since it does not couple to other modes.
Future directions of investigation will involve spin-resolved single particle imaging of the system to observe Cooper paring and the onset of superfluidity.