Finite temperature hydrodynamic modes of trapped quantum gases
  The hydrodynamic equations of an ideal fluid formed by a dilute quantum gas in a parabolic trapping potential are studied analytically and numerically. Due to the appearance of internal modes in the fluid stratified by the trapping potential, the spectrum of low-lying modes is found to be dense in the high-temperature limit, with an infinitely degenerate set of zero-frequency modes. The spectrum for Bose-fluids and Fermi-fluids is obtained and discussed. 
Andr\'as Csord\'as (Research Group for Statistical Physics of the   Hungarian Academy of Sciences, Budapest, Hungary), Rober...