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arXiv · 0902.3021

Observation of Fermi Polarons in a Tunable Fermi Liquid of Ultracold Atoms

Andre Schirotzek·Cheng-Hsun Wu·Ariel Sommer·Martin W. Zwierlein
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Abstract

We have observed Fermi polarons, dressed spin down impurities in a spin up Fermi sea of ultracold atoms. The polaron manifests itself as a narrow peak in the impurities' rf spectrum that emerges from a broad incoherent background. We determine the polaron energy and the quasiparticle residue for various interaction strengths around a Feshbach resonance. At a critical interaction, we observe the transition from polaronic to molecular binding. Here, the imbalanced Fermi liquid undergoes a phase transition into a Bose liquid coexisting with a Fermi sea.

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Andre Schirotzek, Cheng-Hsun Wu, Ariel Sommer, Martin W. Zwierlein. 2009-06-09. Observation of Fermi Polarons in a Tunable Fermi Liquid of Ultracold Atoms. https://doi.org/10.1103/physrevlett.102.230402

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