First and second sound of a unitary Fermi gas in highly oblate harmonic traps

Abstract

We theoretically investigate first and second sound modes of a unitary Fermi gas trapped in a highly oblate harmonic trap at finite temperatures. Following the idea by Stringari and co-workers {[}Phys. Rev. Lett. \textbf{105}, 150402 (2010){]}, we argue that these modes can be described by the simplified two-dimensional two-fluid hydrodynamic equations. Two possible schemes - sound wave propagation and breathing mode excitation - are considered. We calculate the sound wave velocities and discretized sound mode frequencies, as a function of temperature. We find that in both schemes, the coupling between first and second sound modes is large enough to induce significant density fluctuations, suggesting that second sound can be directly observed by measuring \textit{in-situ} density profiles. The frequency of the second sound breathing mode is found to be highly sensitive to the superfluid density.

arXiv comment15 pages, 11 figures, published version in NJP

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Cited by in corpus (8)

• Quantum anomaly and 2D-3D crossover in strongly interacting Fermi gases
• Sound propagation and quantum limited damping in a two-dimensional Fermi gas
• Reduced quantum anomaly in a quasi-2D Fermi superfluid: The significance of the confinement-induced effective range of interactions
• Collective modes of a two-dimensional Fermi gas at finite temperature
• Breathing mode frequency of a strongly interacting Fermi gas across the 2D-3D dimensional crossover
• Two-fluid theory for superfluid system with anisotropic effective masses
• Collective excitations in Bose-Fermi mixtures
• Resonantly interacting $p$-wave Fermi superfluid in two dimensions: Tan's contact and breathing mode