Rostock 2019 – wissenschaftliches Programm
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Q: Fachverband Quantenoptik und Photonik
Q 35: Quantum Gases (Fermions) I
Q 35.8: Vortrag
Mittwoch, 13. März 2019, 16:00–16:15, S HS 037 Informatik
Quantum scale anomaly and spatial coherence in a 2D Fermi superfluid — •Marvin Holten1, Luca Bayha1, Nicolò Defenu2, Antonia Klein1, Puneet Murthy1, Philipp Preiss1, Tilman Enss2, and Selim Jochim1 — 1Physics Institute, University of Heidelberg, Germany — 2Institute for Theoretical Physics, Heidelberg University, Germany
Quantum anomalies are violations of a classical symmetry in the corresponding quantized version of the theory. They appear in quantum field theories when a cut-off has to be introduced to regularize some divergent physical quantity. Quantum anomalies are typically associated with high energy physics only and their influence on experimental observables in other fields is difficult to discern.
In this talk, we report a striking manifestation of a quantum scale anomaly in the breathing mode dynamics of a 2D Fermi superfluid of ultracold atoms. In two independent measurements we have studied both the breathing frequency and the position and pair momentum distribution of the cloud during one breathing mode cycle.
While the atom distributions exhibit self-similar evolution in the weakly interacting BEC and BCS limits, we found a significant violation in the strongly interacting regime. The signature of scale-invariance breaking is enhanced in the first-order coherence function. In particular, the power-law exponents that characterize long-range phase correlations in the system are modified due to this effect, indicating that the quantum anomaly has a significant influence on the critical properties of 2D superfluids.