Collective oscillations of a Fermi gas in the unitarity limit: Temperature effects and the role of pair correlations

Abstract

We present detailed measurements of the frequency and damping of three different collective modes in an ultracold trapped Fermi gas of ${}^6$Li atoms with resonantly tuned interactions. The measurements are carried out over a wide range of temperatures. We focus on the unitarity limit, where the scattering length is much greater than all other relevant length scales. The results are compared to theoretical calculations that take into account Pauli blocking and pair correlations in the normal state above the critical temperature for superfluidity. We show that these two effects nearly compensate each other and the behavior of the gas is close to the one of a classical gas.

8 pages, 5 figures

References in corpus (8)

• Theory of ultracold Fermi gases
• Crossover from a molecular Bose-Einstein condensate to a degenerate Fermi gas
• Collective excitations of a degenerate gas at the BEC-BCS crossover
• Precision Measurements of Collective Oscillations in the BEC-BCS Crossover
• Measurement of the Entropy and Critical Temperature of a Strongly Interacting Fermi Gas
• Finite-Temperature Collective Dynamics of a Fermi Gas in the BEC-BCS Crossover
• Dynamics of a strongly interacting Fermi gas: the radial quadrupole mode
• Frequency and damping of the Scissors Mode of a Fermi gas

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