Erlangen 2018 – scientific programme

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Q: Fachverband Quantenoptik und Photonik

Q 51: Poster: Quantum Optics and Photonics IV

Q 51.21: Poster

Wednesday, March 7, 2018, 16:15–18:15, Redoutensaal

High temperature pairing in a strongly interacting two-dimensional Fermi gas — •Marvin Holten, Puneet Murthy, Luca Bayha, Ralf Klemt, Gerhard Zürn, Philipp Preiss, and Selim Jochim — Physikalisches Institut, University of Heidelberg, Germany

On this poster we present our observation of many-body pairing in a two-dimensional gas of ultracold fermionic atoms at temperatures far above the critical temperature for superfluidity. We use spatially resolved radio-frequency spectroscopy to measure pairing energies spanning a wide range of temperatures and interaction strengths. In the strongly interacting regime, where the scattering length between fermions is on the same order as the inter-particle spacing, the pairing energy in the normal phase significantly exceeds the intrinsic two-body binding energy of the system and shows a clear dependence on local density. This implies, that pairing in this regime is driven by many-body correlations rather than two-body physics. We find this effect to persist at temperatures close to the Fermi temperature, which demonstrates that pairing correlations in strongly interacting two-dimensional fermionic systems are remarkably robust against thermal fluctuations. In addition, we present our study of collective excitation modes of our fermionic atom cloud in its two-dimensional harmonic confinement. Our current results support the observation of a quantum anomaly due to interactions breaking the scale invariance of the two-dimensional gas.