2014/08/12 by Hui Hu, Paul Dyke, Chris Vale +2
Physics and Astronomy · #Acoustics #Atomic and Subatomic Physics Research #Cold Atom Physics and Bose-Einstein Condensates #Coupling (piping) #Fermi Gamma-ray Space Telescope #Fermi gas #Harmonic #Physics #Quantum electrodynamics #Quantum mechanics #Quantum, superfluid, helium dynamics #Second sound #Sound (geography) #Speed of sound #Superfluidity #cond-mat.quant-gas
paper · pdf · doi:10.1088/1367-2630/16/8/083023
published as New Journal of Physics 16, 083023 (2014) · 15 pages, 11 figures, published version in NJP
openalex publication_date 2014/08/12 · arxiv created 2014/10/06 · arxiv updated 2014/10/07 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/06
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 (2010 Phys. Rev. Lett. 105 150402 ), 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 in situ density profiles. The frequency of the second sound breathing mode is found to be highly sensitive to the superfluid density.