Erlangen 2018 – scientific programme
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Q: Fachverband Quantenoptik und Photonik
Q 25: Quantum Gases (Fermions) I
Q 25.4: Talk
Monday, March 5, 2018, 17:00–17:15, K 1.022
Anomalous breaking of scale invariance in a two-dimensional Fermi gas — •Marvin Holten, Luca Bayha, Antonia Klein, Puneet Murthy, Philipp Preiss, and Selim Jochim — Physikalisches Institut, University of Heidelberg, Germany
The frequency of the breathing mode of a classical, two-dimensional Fermi gas in a harmonic confinement is fixed by the scale invariance of the Hamiltonian. On the quantum mechanical level, however, scale invariance is broken by introducing the two dimensional scattering length a2D as a regulator. This is an example for a quantum anomaly in the field of ultracold atoms and leads to a shift of the frequency of the collective breathing mode of the cloud. In this talk, I present our experimental study of this frequency shift for a two component Fermi gas in the strongly interacting regime. We observe a significant shift away from the scale invariant result that depends on both interactions and temperature. A careful consideration of all the additional terms that may lead to explicit breaking of scale invariance is required to distinguish those from the effects caused by the anomaly.