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arXiv · 0907.3032

Collective Oscillations of an Imbalanced Fermi Gas: Axial Compression Modes and Polaron Effective Mass

Sylvain Nascimbene·Nir Navon·Kaijun Jiang·Leticia Tarruell·Martin Teichmann·Jason Mckeever·Frédéric Chevy·Christophe Salomon
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Abstract

We investigate the low-lying compression modes of a unitary Fermi gas with imbalanced spin populations. For low polarization, the strong coupling between the two spin components leads to a hydrodynamic behavior of the cloud. For large population imbalance we observe a decoupling of the oscillations of the two spin components, giving access to the effective mass of the Fermi polaron, a quasi-particle composed of an impurity dressed by particle-hole pair excitations in a surrounding Fermi sea. We find $m^*/m=1.17(10)$, in agreement with the most recent theoretical predictions.

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Sylvain Nascimbene, Nir Navon, Kaijun Jiang, Leticia Tarruell, Martin Teichmann, Jason Mckeever, Frédéric Chevy, Christophe Salomon. 2009-07-17. Collective Oscillations of an Imbalanced Fermi Gas: Axial Compression Modes and Polaron Effective Mass. https://doi.org/10.1103/physrevlett.103.170402

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